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Title: An Agricultural Testament (1943)
Author: Sir Albert Howard
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Title: An Agricultural Testament (1943)
Author: Sir Albert Howard



SIR ALBERT HOWARD, C.I.E., M.A.
Formerly Director of the Institute of Plant Industry Indore,
and Agricultural Adviser to States in Central India and Rajputana



TO
GABRIELLE
WHO IS NO MORE


    The Earth, that's Nature's Mother, is her tomb;
    What is her burying grave, that is her womb.

Romeo and Juliet.



    And Nature, the old nurse, took
    The child upon her knee,
    Saying: 'Here is a story-book
    Thy Father has written for thee.'

    'Come, wander with me,' she said,
    'Into regions yet untrod;
    And read what is still unread
    In the manuscripts of God.'

LONGFELLOW
The Fiftieth Birthday of Agassiz.





PREFACE

Since the Industrial Revolution the processes of growth have been
speeded up to produce the food and raw materials needed by the
population and the factory. Nothing effective has been done to replace
the loss of fertility involved in this vast increase in crop and animal
production. The consequences have been disastrous. Agriculture has
become unbalanced: the land is in revolt: diseases of all kinds are on
the increase: in many parts of the world Nature is removing the worn-out
soil by means of erosion.

The purpose of this book is to draw attention to the destruction of the
earth's capital--the soil; to indicate some of the consequences of this;
and to suggest methods by which the lost fertility can be restored and
maintained. This ambitious project is founded on the work and experience
of forty years, mainly devoted to agricultural research in the West
Indies, India, and Great Britain. It is the continuation of an earlier
book--The Waste Products of Agriculture, published in 1931--in which the
Indore method for maintaining soil fertility by the manufacture of humus
from vegetable and animal wastes was described.

During the last nine years the Indore Process has been taken up at many
centres all over the world. Much additional information on the role of
humus in agriculture has been obtained. I have also had the leisure to
bring under review the existing systems of farming as well as the
organization and purpose of agricultural research. Some attention has
also been paid to the bio-dynamic methods of agriculture in Holland and
in Great Britain, but I remain unconvinced that the disciples of Rudolph
Steiner can offer any real explanation of natural laws or have yet
provided any practical examples which demonstrate the value of their
theories.

The general results of all this are set out in this my Agricultural
Testament. No attempt has been made to disguise the conclusions reached
or to express them in the language of diplomacy. On the contrary, they
have been stated with the utmost frankness. It is hoped that they will be
discussed with the same freedom and that they will open up new lines of
thought and eventually lead to effective action.

It would not have been possible to have written this book without the
help and encouragement of a former colleague in India, Mr. George Clarke,
C.I.E., who held the post of Director of Agriculture in the United
Provinces for ten years (1921-31). He very generously placed at my
disposal his private notes on the agriculture of the Provinces covering a
period of over twenty years, and has discussed with me during the last
three years practically everything in this book. He read many of the
Chapters when they were first drafted, and made a number of suggestions
which have been incorporated in the text.

Many who are engaged in practical agriculture all over the world and who
have adopted the Indore Process have contributed to this book. In a few
cases mention of this assistance has been made in the text. It is
impossible to refer to all the correspondents who have furnished progress
reports and have so freely reported their results. These provided an
invaluable collection of facts and observations which has amply confirmed
my own experience.

Great stress has been laid on a hitherto undiscovered factor in
nutrition--the mycorrhizal association--the living fungous bridge between
humus in the soil and the sap of plants. The existence of such a
symbiosis was first suggested to me on reading an account of the
remarkable results with conifers, obtained by Dr. M. C. Rayner at Wareham
in Dorset in connexion with the operations of the Forestry Commission. If
mycorrhiza occurs generally in the plantation industries and also in our
crops, an explanation of such things as the development of quality,
disease resistance, and the running out of the variety, as well as the
slow deterioration of the soil which follows the use of artificial
manures, would be provided. I accordingly took steps to collect a wide
range of specimens likely to contain mycorrhiza, extending over the whole
of tropical and temperate agriculture. I am indebted to Dr. Rayner and to
Dr. Ida Levisohn for the detailed examination of this material. They have
furnished me with many valuable and suggestive technical reports. For the
interpretation of these laboratory results, as set out in the following
pages, I am myself solely responsible.

I am indebted to a number of Societies for permission to reproduce
information and illustrations which have already been published. Two
other organizations have allowed me to incorporate results which might
well have been regarded as confidential. The Royal Society of London has
permitted me to reprint, in the Chapter on Soil Aeration, a precis of an
illustrated paper which appeared in their Proceedings. The Royal Society
of Arts has provided the blocks for the section on sisal waste. The Royal
Sanitary Institute has agreed to the reproduction in full of a paper read
at the Health Congress, held at Portsmouth in July 1938. The British
Medical Journal has placed at my disposal the information contained in an
article by Dr. Lionel J. Picton, O.B.E. The publishers of Dr. Waksman's
monograph on Humus have allowed me to reprint two long extracts relating
to the properties of humus. Messrs. Arthur Guinness, Sons & Co., Limited,
have agreed to the publication of the details of the composting of town
wastes in their hop garden at Bodiam. Messrs. Walter Duncan & Co. have
allowed the Manager of the Gandrapara Tea Garden to contribute an
illustrated article on the composting of wastes on this fine estate.
Captain J. M. Moubray has sent me a very interesting summary of the work
he is doing at Chipoli in Southern Rhodesia, which is given in Appendix
B.

In making the Indore Process widely known, a number of journals have
rendered yeoman service. In Great Britain The Times and the Journal of
the Royal Society of Arts have published a regular series of letters and
articles. In South Africa the Farmer's Weekly has from the beginning
urged the agricultural community to increase the humus content of the
soil. In Latin America the planters owe much to the Revista del Instituto
de Defensa del Cafe de Costa Rica.

Certain of the largest tea companies in London, Messrs. James Finlay &
Co., Walter Duncan & Co., the Ceylon Tea Plantations Company, Messrs.
Octavius Steel & Co., and others, most generously made themselves
responsible over a period of two years for a large part of the office
expenses connected with the working out and application to the plantation
industries of the Indore Process. They also defrayed the expenses of a
tour to the tea estates of India and Ceylon in 1937. These arrangements
were very kindly made on my behalf by Mr. G. H. Masefield, Chairman of
the Ceylon Tea Plantations Company.

In the work of reducing to order the vast mass of correspondence and
notes on soil fertility' which have accumulated, and in getting the book
into its final shape, I owe much to the ability and devotion of my
private secretary, Mrs. V. M. Hamilton.


A. H. BLACKHEATH,
1 January 1940



In deciding to issue a fifth reprint of my late husband's book,
An Agricultural Testament, I have abstained from introducing any additions
or corrections. To do so would necessitate an almost complete rewriting
of this, the first and perhaps the most trenchant, statement of his views.
Nevertheless, it would be incorrect to deny that the subject matters
treated progressed rapidly even in the course of his own life time; he
himself added to what he said here, and many gallant writers have followed
his lead. A survey of literature presents difficulties, partly owing to
Sir Albert Howard's practice of scattering articles in journals all over
the world. Following on the creation of an Albert Howard Foundation of
Organic Husbandry, the declared aim of which is to continue and make
known the Albert Howard principles, inquiries may be addressed to
the Headquarters of the Foundation at Sharnden Manor, Mayfield, Sussex,
England.


LOUISE E. HOWARD
1949



CONTENTS



I.    INTRODUCTION.

PART I  THE PART PLAYED BY SOIL FERTILITY IN AGRICULTURE

II.   THE NATURE OF SOIL FERTILITY.
III.  THE RESTORATION OF FERTILITY.


PART II   THE INDORE PROCESS

IV.   THE INDORE PROCESS
V.    PRACTICAL APPLICATIONS OF THE INDORE PROCESS
VI.   DEVELOPMENTS OF THE INDORE PROCESS
VII.  DEVELOPMENTS OF THE INDORE PROCESS, GRASS-LAND MANAGEMENT
VIII. DEVELOPMENTS OF THE INDORE PROCESS, THE UTILIZATION OF TOWN WASTES


PART III  HEALTH, INDISPOSITION, AND DISEASE IN AGRICULTURE

IX.   SOIL AERATION
X.    SOME DISEASES OF THE SOIL
XI.   THE RETREAT OF THE CROP AND THE ANIMAL BEFORE THE PARASITE
XII.  SOIL FERTILITY AND NATIONAL HEALTH.


PART IV   AGRICULTURAL RESEARCH

XIII. A CRITICISM OF PRESENT-DAY AGRICULTURAL RESEARCH
XIV.  A SUCCESSFUL EXAMPLE OF AGRICULTURAL RESEARCH


PART V    CONCLUSIONS AND SUGGESTIONS

XV.   A FINAL SURVEY


APPENDIXES

A. COMPOST MANUFACTURE ON A TEA ESTATE IN BENGAL
B. COMPOST MAKING AT CHIPOLI, SOUTHERN RHODESIA
C. THE MANUFACTURE OF HUMUS FROM THE WASTES OF THE TOWN AND THE VILLAGE

=======




CHAPTER I



INTRODUCTION


The maintenance of the fertility of the soil is the first condition of
any permanent system of agriculture. In the ordinary processes of crop
production fertility is steadily lost: its continuous restoration by
means of manuring and soil management is therefore imperative.

In the study of soil fertility the first step is to bring under review
the various systems of agriculture which so far have been evolved. These
fall into four main groups: (1) the methods of Nature--the supreme
farmer--as seen in the primeval forest, in the prairie, and in the ocean;
(2) the agriculture of the nations which have passed away; (3) the
practices of the Orient, which have been almost unaffected by Western
science; and (4) the methods in vogue in regions like Europe and North
America to which a large amount of scientific attention has been paid
during the last hundred years.


NATURE'S METHODS OF SOIL MANAGEMENT

Little or no consideration is paid in the literature of agriculture to
the means by which Nature manages land and conducts her water culture.
Nevertheless, these natural methods of soil management must form the
basis of all our studies of soil fertility.

What are the main principles underlying Nature's agriculture? These can
most easily be seen in operation in our woods and forests.

Mixed farming is the rule: plants are always found with animals: many
species of plants and of animals all live together. In the forest every
form of animal life, from mammals to the simplest invertebrates, occurs.
The vegetable kingdom exhibits a similar range: there is never any
attempt at monoculture: mixed crops and mixed farming are the rule.

The soil is always protected from the direct action of sun, rain, and
wind. In this care of the soil strict economy is the watchword: nothing
is lost. The whole of the energy of sunlight is made use of by the
foliage of the forest canopy and of the undergrowth. The leaves also
break up the rainfall into fine spray so that it can the more easily be
dealt with by the litter of plant and animal remains which provide the
last line of defence of the precious soil. These methods of protection,
so effective in dealing with sun and rain, also reduce the power of the
strongest winds to a gentle air current.

The rainfall in particular is carefully conserved. A large portion is
retained in the surface soil: the excess is gently transferred to the
subsoil and in due course to the streams and rivers. The fine spray
created by the foliage is transformed by the protective ground litter
into thin films of water which move slowly downwards, first into the
humus layer and then into the soil and subsoil. These latter have been
made porous in two ways: by the creation of a well-marked crumb structure
and by a network of drainage and aeration channels made by earthworms and
other burrowing animals. The pore space of the forest soil is at its
maximum so that there is a large internal soil surface over which the
thin films of water can creep. There is also ample humus for the direct
absorption of moisture. The excess drains away slowly by way of the
subsoil. There is remarkably little run-off, even from the primeval rain
forest. When this occurs it is practically clear water. Hardly any soil
is removed. Nothing in the nature of soil erosion occurs. The streams and
rivers in forest areas are always perennial because of the vast quantity
of water in slow transit between the rainstorms and the sea. There is
therefore little or no drought in forest areas because so much of the
rainfall is retained exactly where it is needed. There is no waste
anywhere.

The forest manures itself. It makes its own humus and supplies itself
with minerals. If we watch a piece of woodland we find that a gentle
accumulation of mixed vegetable and animal residues is constantly taking
place on the ground and that these wastes are being converted by fungi
and bacteria into humus. The processes involved in the early stages of
this transformation depend throughout on oxidation: afterwards they take
place in the absence of air. They are sanitary. There is no nuisance of
any kind--no smell, no flies, no dustbins, no incinerators, no artificial
sewage system, no water-borne diseases, no town councils, and no rates.
On the contrary, the forest affords a place for the ideal summer holiday:
sufficient shade and an abundance of pure fresh air. Nevertheless, all
over the surface of the woods the conversion of vegetable and animal
wastes into humus is never so rapid and so intense as during the holiday
months--July to September.

The mineral matter needed by the trees and the undergrowth is obtained
from the subsoil. This is collected in dilute solution in water by the
deeper roots, which also help in anchoring the trees. The details of root
distribution and the manner in which the subsoil is thoroughly combed for
minerals are referred to in a future chapter. Even in soils markedly
deficient in phosphorus trees have no difficulty in obtaining ample
supplies of this element. Potash, phosphate, and other minerals are
always collected in situ and carried by the transpiration current for use
in the green leaves. Afterwards they are either used in growth or
deposited on the floor of the forest in the form of vegetable waste--one
of the constituents needed in the synthesis of humus. This humus is again
utilized by the roots of the trees. Nature's farming, as seen in the
forest, is characterized by two things: (1) a constant circulation of the
mineral matter absorbed by the trees; (2) a constant addition of new
mineral matter from the vast reserves held in the subsoil. There is
therefore no need to add phosphates: there is no necessity for more
potash salts. No mineral deficiencies of any kind occur. The supply of
all the manure needed is automatic and is provided either by humus or by
the soil. There is a natural division of the subject into organic and
inorganic. Humus provides the organic manure: the soil the mineral
matter.

The soil always carries a large fertility reserve. There is no hand to
mouth existence about Nature's farming. The reserves are carried in the
upper layers of the soil in the form of humus. Yet any useless
accumulation of humus is avoided because it is automatically mingled with
the upper soil by the activities of burrowing animals such as earthworms
and insects. The extent of this enormous reserve is only realized when
the trees are cut down and the virgin land is used for agriculture. When
plants like tea, coffee, rubber, and bananas are grown on recently
cleared land, good crops can be raised without manure for ten years or
more. Like all good administrators, therefore, Nature carries strong
liquid reserves effectively invested. There is no squandering of these
reserves to be seen anywhere.

The crops and live stock look after themselves. Nature has never found it
necessary to design the equivalent of the spraying machine and the poison
spray for the control of insect and fungous pests. There is nothing in
the nature of vaccines and serums for the protection of the live stock.
It is true that all kinds of diseases are to be found here and there
among the plants and animals of the forest, but these never assume large
proportions. The principle followed is that the plants and animals can
very well protect themselves even when such things as parasites are to be
found in their midst. Nature's rule in these matters is to live and let
live.

If we study the prairie and the ocean we find that similar principles are
followed. The grass carpet deals with the rainfall very much as the
forest does. There is little or no soil erosion: the run-off is
practically clear water. Humus is again stored in the upper soil. The
best of the grassland areas of North America carried a mixed herbage
which maintained vast herds of bison. No veterinary service was in
existence for keeping these animals alive. When brought into cultivation
by the early settlers, so great was the store of fertility that these
prairie soils yielded heavy crops of wheat for many years without live
stock and without manure.

In lakes, rivers, and the sea mixed farming is again the rule: a great
variety of plants and animals are found living together: nowhere does one
find monoculture. The vegetable and animal wastes are again dealt with by
effective methods. Nothing is wasted. Humus again plays an important part
and is found everywhere in solution, in suspension, and in the deposits
of mud. The sea, like the forest and the prairie, manures itself.

The main characteristic of Nature's farming can therefore be summed up in
a few words. Mother earth never attempts to farm without live stock; she
always raises mixed crops; great pains are taken to preserve the soil and
to prevent erosion; the mixed vegetable and animal wastes are converted
into humus; there is no waste; the processes of growth and the processes
of decay balance one another; ample provision is made to maintain large
reserves of fertility; the greatest care is taken to store the rainfall;
both plants and animals are left to protect themselves against disease

In considering the various man-made systems of agriculture, which so far
have been devised, it will be interesting to see how far Nature's
principles have been adopted, whether they have ever been improved upon,
and what happens when they are disregarded.


THE AGRICULTURE OF THE NATIONS WHICH HAVE PASSED AWAY

The difficulties inherent in the study of the agriculture of the nations
which are no more are obvious. Unlike their buildings, where it is
possible from a critical study of the buried remains of cities to
reproduce a picture of bygone civilizations, the fields of the ancients
have seldom been maintained. The land has either gone back to forest or
has been used for one system of farming after another.

In one case, however, the actual fields of a bygone people have been
preserved together with the irrigation methods by which these lands were
made productive. No written records, alas, have come down to us of the
staircase cultivation of the ancient Peruvians, perhaps one of the oldest
forms of Stone Age agriculture. This arose either in mountains or in the
upland areas under grass because of the difficulty, before the discovery
of iron, of removing the dense forest growth. In Peru irrigated staircase
farming seems to have reached its highest known development. More than
twenty years ago the National Geographical Society of the United States
sent an expedition to study the relics of this ancient method of
agriculture, an account of which was published by O. F. Cook in the
Society's Magazine of May 1916, under the title: 'Staircase Farms of the
Ancients.' The system of the megalithic people of old Peru was to
construct a stairway of terraced fields up the slopes of the mountains,
tier upon tier, sometimes as many as fifty in number. The outer retaining
walls of these terraces were made of large stones which fit into one
another with such accuracy that even at the present day, like those of
the Egyptian pyramids, a knife blade cannot be inserted between them.
After the retaining wall was built, the foundation of the future field
was prepared by means of coarse stones covered with clay. On this basis
layers of soil, several feet thick, originally imported from beyond the
great mountains, were super-imposed and then levelled for irrigation. The
final result was a small flat field with only just sufficient slope for
artificial watering. In other words, a series of huge flower pots, each
provided with ample drainage below, was prepared with incredible labour
by this ancient people for their crops. Such were the megalithic
achievements in agriculture, beside which 'our undertakings sink into
insignificance in face of what this vanished race accomplished. The
narrow floors and steep walls of rocky valleys that would appear utterly
worthless and hopeless to our engineers were transformed, literally made
over, into fertile lands and were the homes of teeming populations in
pre-historic days' (O. F. Cook). The engineers of old Peru did what they
did through necessity because iron, steel, reinforced concrete, and the
modern power units had not been invented. The plunder of the forest soil
was beyond their reach.

These terraced fields had to be irrigated. Water had to be led to them
over immense distances by means of aqueducts. Prescott states that one
which traversed the district of Condesuyu measured between four and five
hundred miles. Cook gives a photograph of one of these channels as a thin
dark line traversing a steep mountain wall many hundreds of feet above
the valley.

These ancient methods of agriculture are represented at the present day
by the terraced cultivation of the Himalayas, of the mountainous areas of
China and Japan, and of the irrigated rice fields so common in the hills
of South India, Ceylon, and the Malayan Archipelago. Conway's
description, published in 1894, of the terraces of Hunza on the
North-West Frontier of India and of the canal, carried for long distances
across the face of precipices to the one available supply of perennial
water--the torrent from the Ultor glacier--tallies almost completely with
what he found in 1901 in the Bolivian Andes. This distinguished scholar
and mountaineer considered that the native population of Hunza of the
present day is living in a stage of civilization that must bear no little
likeness to that of the Peruvians under Inca government. An example of
this ancient method of farming has thus been preserved through the ages.
In a future chapter the relation which exists between the nutritional
value of the food grown on these irrigated terraces and the health of the
people will be discussed. This relic of the past is interesting from the
point of view of quality in food as well as from its historical value.

Some other systems of agriculture of the past have come down to us in the
form of written records which have furnished ample material for
constructive research. In the case of Rome in particular a fairly
complete account of the position of agriculture, from the period of the
monarchy to the fall of the Roman Empire, is available; the facts can be
conveniently followed in the writings of Mommsen, Heitland, and other
scholars. In the case of Rome the Servian Reform (Servius Tullius,
578-534 B.C.) shows very clearly not only that the agricultural class
originally preponderated in the State but also that an effort was made to
maintain the collective body of freeholders as the pith and marrow of the
community. The conception that the constitution itself rested on the
freehold system permeated the whole policy of Roman war and conquest. The
aim of war was to increase the number of its freehold members.


'The vanquished community was either compelled to merge entirely into
the yeomanry of Rome, or, if not reduced to this extremity, it was
required, not to pay a war contribution or a fixed tribute, but to cede
a portion, usually a third part, of its domain, which was thereupon
regularly occupied by Roman farms. Many nations have gained victories
and made conquests as the Romans did; but none has equalled the Roman in
thus making the ground he had won his own by the sweat of his brow, and
in securing by the ploughshare what had been gained by the lance. That
which is gained by war may be wrested from the grasp by war again, but
it is not so with the conquests made by the plough; whilst the Romans
lost many battles, they scarcely ever on making peace ceded Roman soil,
and for this result they were indebted to the tenacity with which the
farmers clung to their fields and homesteads. The strength of man and of
the State lies in their dominion over the soil; the strength of Rome was
built on the most extensive and immediate mastery of her citizens over
the soil, and on the compact unity of the body which thus acquired so
firm a hold.' (Mommsen.)


These splendid ideals did not persist. During the period which elapsed
between the union of Italy and the subjugation of Carthage, a gradual
decay of the farmers set in; the small-holdings ceased to yield any
substantial clear return; the cultivators one by one faced ruin; the
moral tone and frugal habits of the earlier ages of the Republic were
lost; the land of the Italian farmers became merged into the larger
estates. The landlord capitalist became the centre of the subject. He
not only produced at a cheaper rate than the farmer because he had more
land, but he began to use slaves. The same space which in the olden
time, when small-holdings prevailed, had supported from a hundred to a
hundred and fifty families was now occupied by one family of free
persons and about fifty, for the most part unmarried, slaves. 'If this
was the remedy by which the decaying national economy was to be restored
to vigour, it bore, unhappily, an aspect of extreme resemblance to
disease' (Mommsen). The main causes of this decline appear to have been
fourfold: the constant drain on the manhood of the country-side by the
legions, which culminated in the two long wars with Carthage; the
operations of the Roman capitalist landlords which 'contributed quite as
much as Hamilcar and Hannibal to the decline in the vigour and the
number of the Italian people' (Mommsen); failure to work out a balanced
agriculture between crops and live stock and to maintain the fertility
of the soil; the employment of slaves instead of free labourers. During
this period the wholesale commerce of Latium passed into the hands of
the large landed proprietors who at the same time were the speculators
and capitalists. The natural consequence was the destruction of the
middle classes, particularly of the small-holders, and the development
of landed and moneyed lords on the one hand and of an agricultural
proletariat on the other. The power of capital was greatly enhanced by
the growth of the class of tax-farmers and contractors to whom the State
farmed out its indirect revenues for a fixed sum. Subsequent political
and social conflicts did not give real relief to the agricultural
community. Colonies founded to secure Roman sovereignty over Italy
provided farms for the agricultural proletariat, but the root causes of
the decline in agriculture were not removed in spite of the efforts of
Cato and other reformers. A capitalist system of which the apparent
interests were fundamentally opposed to a sound agriculture remained
supreme. The last half of the second century saw degradation and more
and more decadence. Then came Tiberius Gracchus and the Agrarian Law
with the appointment of an official commission to counteract the
diminution of the farmer class by the comprehensive establishment of new
small-holdings from the whole Italian landed property at the disposal of
the State: eighty thousand new Italian farmers were provided with land.
These efforts to restore agriculture to its rightful place in the State
were accompanied by many improvements in Roman agriculture which,
unfortunately, were most suitable for large estates. Land no longer able
to produce corn became pasture; cattle now roamed over large ranches;
the vine and the olive were cultivated with commercial success. These
systems of agriculture, however, had to be carried on with slave labour,
the supply of which had to be maintained by constant importation. Such
extensive methods of farming naturally failed to supply sufficient food
for the population of Italy. Other countries were called upon to furnish
essential foodstuffs; province after province was conquered to feed the
growing proletariat with corn. These areas in turn slowly yielded to the
same decline which had taken place in Italy. Finally the wealthy classes
abandoned the depopulated remnants of the mother country and built
themselves a new capital at Constantinople. The situation had to be
saved by a migration to fresh lands. In their new capital the Romans
relied on the unexhausted fertility of Egypt as well as on that of Asia
Minor and the Balkan and Danubian provinces.

Judged by the ordinary standards of achievement the agricultural history
of the Roman Empire ended in failure due to inability to realize the
fundamental principle that the maintenance of soil fertility coupled with
the legitimate claims of the agricultural population should never have
been allowed to come in conflict with the operations of the capitalist.
The most important possession of a country is its population. If this is
maintained in health and vigour everything else will follow; if this is
allowed to decline nothing, not even great riches, can save the country
from eventual ruin. It follows, therefore, that the strongest possible
support of capital must always be a prosperous and contented
country-side. A working compromise between agriculture and finance should
therefore have been evolved. Failure to achieve this naturally ended in
the ruin of both.


THE PRACTICES OF THE ORIENT

In the agriculture of Asia we find ourselves confronted with a system of
peasant farming which in essentials soon became stabilized. What is
happening to-day in the small fields of India and China took place many
centuries ago. There is here no need to study historical records or to
pay a visit to the remains of the megalithic farming of the Andes. The
agricultural practices of the Orient have passed the supreme test--they
are almost as permanent as those of the primeval forest, of the prairie
or of the ocean. The small-holdings of China, for example, are still
maintaining a steady output and there is no loss of fertility after forty
centuries of management. What are the chief characteristics of this
Eastern farming?

The holdings are minute. Taking India as an example, the relation between
man power and cultivated area is referred to in the Census Report of 1931
as follows: 'For every agriculturalist there is 2.9 acres of cropped land
of which 0.65 of an acre is irrigated. The corresponding figures of 1921
are 2.7 and 0.61.' These figures illustrate how intense is the struggle
for existence in this portion of the tropics. These small-holdings are
often cultivated by extensive methods (those suitable for large areas)
which utilize neither the full energies of man or beast nor the potential
fertility of the soil.

If we turn to the Far East, to China and Japan, a similar system of
small-holdings is accompanied by an even more intense pressure of
population both human and bovine. In the introduction to FARMERS OF FORTY
CENTURIES, King states that the three main islands of Japan had in 1907 a
population of 46,977,000, maintained on 20,000 square miles of cultivated
fields. This is at the rate of 2,349 to the square mile or more than
three people to each acre. In addition, Japan fed on each square mile of
cultivation a very large animal population--69 horses and 56 cattle,
nearly all employed in labour; 825 poultry; 13 swine, goats, and sheep.
Though no accurate statistics are available in China, the examples quoted
by King reveal a condition of affairs not unlike that in Japan. In the
Shantung Province a farmer with a family of twelve kept one donkey, one
cow, and two pigs on 2.5 acres of cultivated land--a density of
population at the rate of 3,072 people, 256 donkeys, 256 cattle, and 512
pigs per square mile. The average of seven Chinese holdings visited gave
a maintenance capacity of 1,783 people, 212 cattle or donkeys, and 399
pigs--nearly 2,000 consumers and 400 rough food transformers per square
mile of farmed land. In comparison with these remarkable figures, the
corresponding statistics for 1900 in the case of the United States per
square mile were: population 61, horses and mules 30.

Food and forage crops are predominant. The primary function of Eastern
agriculture is to supply the cultivators and their cattle with food. This
automatically follows because of the pressure of the population on the
land: the main hunger the soil has to appease is that of the stomach. A
subsidiary hunger is that of the machine which needs raw materials for
manufacture. This extra hunger is new but has developed considerably
since the opening of the Suez Canal in 1869 (by which the small fields of
the cultivator have been brought into effective contact with the markets
of the West) and the establishment of local industries like cotton and
jute. To both these hungers soil fertility has to respond. We know from
long experience that the fields of India can respond to the hunger of the
stomach. Whether they can fulfil the added demands of the machine remains
to be seen. The Suez Canal has only been in operation for seventy years.
The first cotton mill in India was opened in 1818 at Fort Gloster, near
Calcutta. The jute industry of Bengal has grown up within a century. Jute
was first exported in 1838. The first jute mill on the Hoogly began
operations in 1855. These local industries as well as the export trade in
raw products for the use of the factories of the West are an extra drain
on soil fertility. Their future well-being and indeed their very
existence is only possible provided adequate steps are taken to maintain
this fertility. There is obviously no point in establishing cotton and
jute mills in India, in founding trading agencies like those of Calcutta
and in building ships for the conveyance of raw products unless such
enterprises are stable and permanent. It would be folly and an obvious
waste of capital to pursue such activities if they are founded only on
the existing store of soil fertility. All concerned in the hunger of the
machine--government, financiers, manufacturers, and distributors--must
see to it that the fields of India are equal to the new burden which has
been thrust upon her during the last fifty years or so. The demands of
commerce and industry on the one hand and the fertility of the soil on
the other must be maintained in correct relation the one to the other.

The response of India to the two hungers--the stomach and the
machine--will be evident from a study of Table I, in which the area in
acres under food and fodder crops is compared with that under money
crops.

The chief food crops in order of importance are rice, pulses millets,
wheat, and fodder crops. The money crops are more varied; cotton and oil
seeds are the most important, followed by jute and other fibres, tobacco,
tea, coffee, and opium. It will be seen that food and fodder crops
comprise 86 per cent. of the total area under crops and that money crops,
as far as extent is concerned, are less important, and constitute only
one-seventh of the total cultivated area.


TABLE 1

Agricultural Statistics of British India, 1935-6
Area, in acres, under food and fodder crops

Rice                                    79,888,000
Millets                                 38,144,000
Wheat                                   25,150,000
Gram                                    14,897,000
Pulses and other food grains            29,792,000
Fodder crops                            10,791,000
Condiments, spices, fruits, vegetables
and miscellaneous food crops             8,308,000
Barley                                   6,178,000
Maize                                    6,211,000
Sugar                                    4,038,000

Total food and fodder crops            223,397,000


Area, in acres, under money crops

Cotton                                  15,761,000
Oil seeds, chiefly ground-nuts,
sesamum, rape, mustard and linseed      15,662,000
Jute and other fibres                    2,706,000
Dyes, tanning materials, drugs,
narcotics, and miscellaneous             1,458,000
Tobacco                                  1,230,000
Tea                                        787,000
Coffee                                      97,000
Indigo                                      40,000
Opium                                       10,000

Total money crops                       37,751,000


One interesting change in the production of Indian food crops has taken
place during the last twenty-five years. The output of sugar used to be
insufficient for the towns, and large quantities were imported from Java,
Mauritius, and the continent of Europe. To-day, thanks to the work at
Shahjahanpur in the United Provinces, the new varieties of cane bred at
Coimbatore and the protection now enjoyed by the sugar industry, India is
almost self-supporting as far as sugar is concerned. The pre-war average
amount of sugar imported was 634,000 tons; in 1937-8 the total had fallen
to 14,000 tons.

Mixed crops are the rule. In this respect the cultivators of the Orient
have followed Nature's method as seen in the primeval forest. Mixed
cropping is perhaps most universal when the cereal crop is the main
constituent. Crops like millets, wheat, barley, and maize are mixed with
an appropriate subsidiary pulse, sometimes a species that ripens much
later than the cereal. The pigeon pea (Cajanus indicus Spreng.), perhaps
the most important leguminous crop of the Gangetic alluvium, is grown
either with millets or with maize. The mixing of cereals and pulses
appears to help both crops. When the two grow together the character of
the growth improves. Do the roots of these crops excrete materials useful
to each other? Is the mycorrhizal association found in the roots of these
tropical legumes and cereals the agent involved in this excretion?
Science at the moment is unable to answer these questions: she is only
now beginning to investigate them Here we have another instance where the
peasants of the East have anticipated and acted upon the solution of one
of the problems which Western science is only just beginning to
recognize. Whatever may be the reason why crops thrive best when
associated in suitable combinations, the fact remains that mixtures
generally give better results than monoculture. This is seen in Great
Britain in the growth of dredge corn, in mixed crops of wheat and beans,
vetches and rye, clover and rye-grass, and in intensive vegetable growing
under glass. The produce raised under Dutch lights has noticeably
increased since the mixed cropping of the Chinese vegetable growers of
Australia has been copied. (Mr. F. A. Secrett was, I believe, the first
to introduce this system on a large scale into Great Britain. He informed
me that he saw it for the first time at Melbourne.)

A balance between live stock and crops is always maintained. Although
crops are generally more important than animals in Eastern agriculture,
we seldom or never find crops without animals. This is because oxen are
required for cultivation and buffaloes for milk. (The buffalo is the
milch cow of the Orient and is capable not only of useful labour in the
cultivation of rice, but also of living and producing large quantities of
rich milk on a diet on which the best dairy cows of Europe and America
would starve. The acclimatization of the Indian buffalo in the villages
of the Tropics--Africa, Central America, the West Indies in
particular--would do much to improve the fertility of the soil and the
nutrition of the people.)

Nevertheless, the waste products of the animal, as is often the case in
other parts of the world, are not always fully utilized for the land. The
Chinese have for ages past recognized the importance of the urine of
animals and the great value of animal wastes in the preparation of
composts. In India far less attention is paid to these wastes and a large
portion of the cattle dung available is burnt for fuel. On the other
hand, in most Oriental countries human wastes find their way back to the
land. In China these are collected for manuring the crops direct. In
India they are concentrated on the zone of highly manured land
immediately round each village. If the population or a portion of it
could be persuaded to use a more distant zone for a few years, the area
of village lands under intensive agriculture could at least be doubled.
Here is an opportunity for the new system of government in India to raise
production without the expenditure of a single rupee. In India there are
500,000 villages each of which is surrounded by a zone of very fertile
land which is constantly being over-manured by the habits of the people.
If we examine the crops grown on this land we find that the yields are
high and the plants are remarkably free from disease. Although half a
million examples of the connexion between a fertile soil and a healthy
plant exist in India alone, and these natural experiments have been in
operation for centuries before experiment stations like Rothamsted were
ever thought of, modern agricultural science takes no notice of the
results and resolutely refuses to accept them as evidence, largely
because they lack the support furnished by the higher mathematics. They
also dispose of one of the ideas of the disciples of Rudolph Steiner, who
argue that the use of human wastes in agriculture is harmful.

Leguminous plants are common. Although it was not till 1888, after a
protracted controversy lasting thirty years, that Western science finally
accepted as proved the important part played by pulse crops in enriching
the soil, centuries of experience had taught the peasants of the East the
same lesson. The leguminous crop in the rotation is everywhere one of
their old fixed practices. In some areas, such as the Indo-Gangetic
plain, one of these pulses--the pigeon pea--is also made use of as a
subsoil cultivator. The deep spreading root system is used to promote the
aeration of the closely packed silt soils, which so closely resemble
those of the Holland Division of Lincolnshire in Great Britain.

Cultivation is generally superficial and is carried out by wooden ploughs
furnished with an iron point. Soil-inverting ploughs, as used in the West
for the destruction of weeds, have never been designed by Eastern
peoples. The reasons for this appear to be two: (1) soil inversion for
the destruction of weeds is not necessary in a hot climate where the same
work is done by the sun for nothing; (2) the preservation of the level of
the fields is essential for surface drainage, for preventing local
waterlogging, and for irrigation. Another reason for this surface
cultivation has recently been pointed out. The store of nitrogen in the
soil in the form of organic matter has to be carefully conserved: it is
part of the cultivator's working capital. Too much cultivation and deep
ploughing would oxidize this reserve and the balance of soil fertility
would soon be destroyed.

Rice is grown whenever possible. By far the most important crop in the
East is rice. In India, as has already been pointed out, the production
of rice exceeds that of any two food crops put together. Whenever the
soil and water supply permit, rice is invariably grown. A study of this
crop is illuminating. At first sight rice appears to contradict one of
the great principles of the agricultural science of the Occident, namely,
the dependence of cereals on nitrogenous manures. Large crops of rice are
produced in many parts of India on the same land year after year without
the addition of any manure whatever. The rice fields of the country
export paddy in large quantities to the centres of population or abroad,
but there is no corresponding import of combined nitrogen.

Taking Burma as an example of an area exporting rice beyond seas, during
the twenty years ending 1924, about 25,000,000 tons of paddy have been
exported from a tract roughly 10,000,000 acres in area. As unhusked rice
contains about 1.2 per cent. of nitrogen the amount of this element,
shipped overseas during twenty years or destroyed in the burning of the
husk, is in the neighbourhood of 300,000 tons. As this constant drain of
nitrogen is not made up for by the import of manure, we should expect to
find a gradual loss of fertility. Nevertheless, this does not take place
either in Burma or in Bengal, where rice has been grown on the same land
year after year for centuries. Clearly the soil must obtain fresh
supplies of nitrogen from somewhere, otherwise the crop would cease to
grow. The only likely source is fixation from the atmosphere, probably in
the submerged algal film on the surface of the mud. This is one of the
problems of tropical agriculture which is now being investigated.

Where does the rice crop obtain its nitrogen? One source in all
probability is fixation from the atmosphere in the submerged algal film
on the surface of the mud. Another is the rice nursery itself, where the
seedlings are raised on land heavily manured with cattle dung. Large
quantities of nitrogen and other nutrients are stored in the seedling
itself; this at transplanting time contains a veritable arsenal of
reserves of all kinds which carry the plant successfully through this
process and probably also furnish some of the nitrogen needed during
subsequent growth. The manuring of the rice seedling illustrates a very
general principle in agriculture, namely, the importance of starting a
crop in a really fertile soil and so arranging matters that the plant can
absorb a great deal of what it needs as early as possible in its
development.

There is an adequate supply of labour. Labour is everywhere abundant, as
would naturally follow from the great density of the rural population.
Indeed, in India it is so great that if the leisure time of the
cultivators and their cattle for a single year could be calculated as
money at the local rates a perfectly colossal figure would be obtained.
This leisure, however, is not altogether wasted. It enables the
cultivators and their oxen to recover from the periods of intensive work
which precede the sowing of the crops and which are needed at harvest
time. At these periods time is everything: everybody works from sunrise
to sunset. The preparation of the land and the sowing of the crops need
the greatest care and skill; the work must be completed in a very short
time so that a large labour force is essential.

It will be observed that in this peasant agriculture the great pressure
of population on the soil results in poverty, most marked where, as in
India, extensive methods are used on small-holdings which really need
intensive farming. It is amazing that in spite of this unfavourable
factor soil fertility should have been preserved for centuries: this is
because natural means have been used and not artificial manures. The
crops are able to withstand the inroads of insects and fungi without a
thin film of protective poison.


THE AGRICULTURAL METHODS OF THE OCCIDENT

If we take a wide survey of the contribution which is being made by the
fields of the West, we find that they are engaged in trying to satisfy no
less than three hungers: (1) the local hunger of the rural population,
including the live stock; (2) the hunger of the growing urban areas, the
population of which is unproductive from the point of view of soil
fertility; and (3) the hunger of the machine avid for a constant stream
of the raw materials required for manufacture. The urban population
during the last century has grown out of all knowledge; the needs of the
machine increase as it becomes more and more efficient; falling profits
are met by increasing the output of manufactured articles. All this adds
to the burden on the land and to the calls on its fertility. It will not
be without interest to analyse critically the agriculture of the West and
see how it is fitting itself for its growing task. This can be done by
examining its main characteristics. These are as follows:

The holding tends to increase in size. There is a great variation in the
size of the agricultural holdings of the West from the small family units
of France and Switzerland to the immense collective farms of Russia and
the spacious ranches of the United States and Argentina. Side by side
with this growth in the size of the farm is the diminution of the number
of men per square mile. In Canada, for example, the number of workers per
1,000 acres of cropped land fell from 26 in 1911 to 16 in 1926. Since
these data were published the size of the working population has shrunk
still further. This state of things has arisen from the scarcity and
dearness of labour which has naturally led to the study of labour-saving
devices.

Monoculture is the rule. Almost everywhere crops are grown in pure
culture. Except in temporary leys, mixed crops are rare. On the rich
prairie lands of North America even rotations are unknown: crops of wheat
follow one another and no attempt is made to convert the straw into humus
by means of the urine and dung of cattle. The straw is a tiresome
encumbrance and is burnt off annually.

The machine is rapidly replacing the animal. Increasing mechanization is
one of the main features of Western agriculture. Whenever a machine can
be invented which saves human or animal labour its spread is rapid.
Engines and motors of various kinds are the rule everywhere. The
electrification of agriculture is beginning. The inevitable march of the
combine harvester in all the wheat-producing areas of the world is one of
the latest examples of the mechanization of the agriculture of the West.
Cultivation tends to be quicker and deeper. There is a growing feeling
that the more and the deeper the soil is stirred the better will be the
crop. The invention of the gyrotiller, a heavy and expensive soil churn,
is one of the answers to this demand. The slaves of the Roman Empire have
been replaced by mechanical slaves. The replacement of the horse and the
ox by the internal combustion engine and the electric motor is, however,
attended by one great disadvantage. These machines do not void urine and
dung and so contribute nothing to the maintenance of soil fertility. In
this sense the slaves of Western agriculture are less efficient than
those of ancient Rome.

Artificial manures are widely used. The feature of the manuring of the
West is the use of artificial manures. The factories engaged during the
Great War in the fixation of atmospheric nitrogen for the manufacture of
explosives had to find other markets, the use of nitrogenous fertilizers
in agriculture increased, until to-day the majority of farmers and market
gardeners base their manurial programme on the cheapest forms of nitrogen
(N), phosphorus (P), and potassium (K) on the market. What may be
conveniently described as the NPK mentality dominates farming alike in
the experimental stations and the country-side. Vested interests,
entrenched in time of national emergency, have gained a stranglehold.

Artificial manures involve less labour and less trouble than farm-yard
manure. The tractor is superior to the horse in power and in speed of
work: it needs no food and no expensive care during its long hours of
rest. These two agencies have made it easier to run a farm. A
satisfactory profit and loss account has been obtained. For the moment
farming has been made to pay. But there is another side to this picture.
These chemicals and these machines can do nothing to keep the soil in
good heart. By their use the processes of growth can never be balanced by
the processes of decay. All that they can accomplish is the transfer of
the soil's capital to current account. That this is so will be much
clearer when the attempts now being made to farm without any animals at
all march to their inevitable failure.

Diseases are on the increase. With the spread of artificials and the
exhaustion of the original supplies of humus, carried by every fertile
soil, there has been a corresponding increase in the diseases of crops
and of the animals which feed on them. If the spread of foot-and-mouth
disease in Europe and its comparative insignificance among well fed
animals in the East are compared, or if the comparison is made between
certain areas in Europe, the conclusion is inevitable that there must be
an intimate connexion between faulty methods of agriculture and animal
disease. In crops like potatoes and fruit, the use of the poison spray
has closely followed the reduction in the supplies of farm-yard manure
and the diminution of fertility.

Food preservation processes are also on the increase. A feature of the
agriculture of the West is the development of food preservation processes
by which the journey of products like meat, milk, vegetables, and fruit
between the soil and the stomach is prolonged. This is done by freezing,
by the use of carbon dioxide, by drying, and by canning. Although food is
preserved for a time in this way, what is the effect of these processes
on the health of the community during a period of, say, twenty-five
years? Is it possible to preserve the first freshness of food? If so then
science will have made a very real contribution.

Science has been called in to help production. Another of the features of
the agriculture of the West is the development of agricultural science.
Efforts have been made to enlist the help of a number of separate
sciences in studying the problems of agriculture and in increasing the
production of the soil. This has entailed the foundation of numerous
experiment stations which every year pour out a large volume of advice in
the shape of printed matter.

These mushroom ideas of agriculture are failing; mother earth deprived of
her manurial rights is in revolt; the land is going on strike; the
fertility of the soil is declining. An examination of the areas which
feed the population and the machines of a country like Great Britain
leaves no doubt that the soil is no longer able to stand the strain. Soil
fertility is rapidly diminishing, particularly in the United States,
Canada, Africa, Australia, and New Zealand. In Great Britain itself real
farming has already been given up except on the best lands. The loss of
fertility all over the world is indicated by the growing menace of soil
erosion. The seriousness of the situation is proved by the attention now
being paid to this matter in the press and by the various
Administrations. In the United States, for example, the whole resources
of government are being mobilized to save what is left of the good earth.

The agricultural record has been briefly reviewed from the standpoint of
soil fertility. The main characteristics of the various methods of
agriculture have been summarized. The most significant of these are the
operations of Nature as seen in the forest. There the fullest use is made
of sunlight and rainfall in raising heavy crops of produce and at the
same time not only maintaining fertility but actually building up large
reserves of humus. The peasants of China, who pay great attention to the
return of all wastes to the land, come nearest to the ideal set by
Nature. They have maintained a large population on the land without any
falling off in fertility. The agriculture of ancient Rome failed because
it was unable to maintain the soil in a fertile condition. The farmers of
the West are repeating the mistakes made by Imperial Rome. The soils of
the Roman Empire, however, were only called upon to assuage the hunger of
a relatively small population. The demands of the machine were then
almost non-existent. In the West there are relatively more stomachs to
fill while the growing hunger of the machine is an additional burden on
the soil. The Roman Empire lasted for eleven centuries. How long will the
supremacy of the West endure? The answer depends on the wisdom and
courage of the population in dealing with the things that matter. Can
mankind regulate its affairs so that its chief possession--the fertility
of the soil--is preserved? On the answer to this question the future of
civilization depends.


BIBLIOGRAPHY

Agricultural Statistics of India, 1, Delhi, 1938.

HOWARD, A., and HOWARD, G. L. C. The Development of Indian
Agriculture, Oxford University Press, 1929.

KING, F. H. Farmers of Forty Centuries or Permanent Agriculture
in China, Korea, and Japan, London, 1916.

LYMINGTON, VISCOUNT. Famine in England, London, 1938.

MOMMSEN, THEODOR. The History of Rome, transl. Dickson, London, 1894.

WRENCH, G. T. The Wheel of Health, London, 1938.





PART I THE PART PLAYED BY SOIL FERTILITY IN AGRICULTURE




CHAPTER II



THE NATURE OF SOIL FERTILITY


What is this soil fertility? What exactly does it mean? How does it
affect the soil, the crop, and the animal? How can we best investigate
it? An attempt will be made in this chapter to answer these questions and
to show why soil fertility must be the basis of any permanent system of
agriculture.

The nature of soil fertility can only be understood if it is considered
in relation to Nature's round. In this study we must at the outset
emancipate ourselves from the conventional approach to agricultural
problems by means of the separate sciences and above all from the
statistical consideration of the evidence afforded by the ordinary field
experiment. Instead of breaking up the subject into fragments and
studying agriculture in piecemeal fashion by the analytical methods of
science, appropriate only to the discovery of new facts, we must adopt a
synthetic approach and look at the wheel of life as one great subject and
not as if it were a patchwork of unrelated things.

All the phases of the life cycle are closely connected; all are integral
to Nature's activity; all are equally important; none can be omitted. We
have therefore to study soil fertility in relation to a natural working
system and to adopt methods of investigation in strict relation to such a
subject. We need not strive after quantitative results: the qualitative
will often serve. We must look at soil fertility as we would study a
business where the profit and loss account must be taken along with the
balance-sheet, the standing of the concern, and the method of management.
It is the 'altogetherness' which matters in business, not some particular
transaction or the profit or loss of the current year. So it is with soil
fertility. We have to consider the wood, not the individual trees.

The wheel of life is made up of two processes--growth and decay. The one
is the counterpart of the other.

Let us first consider growth. The soil yields crops; these form the food
of animals: crops and animals are taken up into the human body and are
digested there. The perfectly grown, normal, vigorous human being is the
highest natural development known to us. There is no break in the chain
from soil to man; this section of the wheel of life is uninterrupted
throughout; it is also an integration; each step depends on the last. It
must therefore be studied as a working whole.

The energy for the machinery of growth is derived from the sun; the
chlorophyll in the green leaf is the mechanism by which this energy is
intercepted; the plant is thereby enabled to manufacture food--to
synthesize carbohydrates and proteins from the water and other substances
taken up by the roots and the carbon dioxide of the atmosphere. The
efficiency of the green leaf is therefore of supreme importance; on it
depends the food supply of this planet, our well-being, and our
activities. There is no alternative source of nutriment. Without sunlight
and the green leaf our industries, our trade, and our possessions would
soon be useless.

The chief factors on which the work of the green leaf depends are the
condition of the soil and its relation to the roots of the plant. The
plant and the soil come into gear by means of the root system in two
ways--by the root hairs and by the mycorrhizal association. The first
condition for this gearing is that the internal surface of the soil--the
pore space--shall be as large as possible throughout the life of the
crop. It is on the walls of this pore space, which are covered with thin
water films, that the essential activities of the soil take place. The
soil population, consisting mainly of bacteria, fungi and protozoa, carry
on their life histories in these water films.

The contact between the soil and the plant which is best understood takes
place by means of the root hairs. These are prolongations of the outer
layer of cells of the young root. Their duty is to absorb from the thin
films of moisture on the walls of the pore space the water and dissolved
salts needed for the work of the green leaves: no actual food can reach
the plant in this way, only simple things which are needed by the green
leaf to synthesize food. The activities of the pore space depend on
respiration for which adequate quantities of oxygen are essential. A
corresponding amount of carbon dioxide is the natural by-product. To
maintain the oxygen supply and to reduce the amount of carbon dioxide,
the pore spaces must be kept in contact with the atmosphere. The soil
must be ventilated. Hence the importance of cultivation.

As most of the soil organisms possess no chlorophyll, and, moreover, have
to work in the dark, they must be supplied with energy. This is obtained
by the oxidation of humus--the name given to a complex residue of partly
oxidized vegetable and animal matter together with the substances
synthesized by the fungi and bacteria which break down these wastes. This
humus also helps to provide the cement which enables the minute mineral
soil particles to aggregate into larger compound particles and so
maintain the pore space. If the soil is deficient in humus, the volume of
the pore space is reduced; the aeration of the soil is impeded; there is
insufficient organic matter for the soil population; the machinery of the
soil runs down; the supply of oxygen, water, and dissolved salts needed
by the root hairs is reduced; the synthesis of carbohydrates and proteins
in the green leaf proceeds at a lower tempo; growth is affected. Humus is
therefore an essential material for the soil if the first phase of the
life cycle is to function.

There is another reason why humus is important. Its presence in the soil
is an essential condition for the proper functioning of the second
contact between soil and plant--the mycorrhizal relationship. By means of
this connexion certain soil fungi, which live on humus, are able to
invade the living cells of the young roots and establish an intimate
relation with the plant, the details of which symbiosis are still being
investigated and discussed. Soil fungus and plant cells live together in
closer partnership than the algal and fungous constituents of the lichen
do. How the fungus benefits has yet to be determined. How the plant
profits is easier to understand. If a suitable preparation of such roots
is examined under the microscope, all stages in the digestion of the
fungous mycelium can be seen. At the end of the partnership the root
consumes the fungus and in this manner is able to absorb the
carbohydrates and proteins which the fungus obtains partly from the humus
in the soil. The mycorrhizal association therefore is the living bridge
by which a fertile soil (one rich in humus) and the crop are directly
connected and by which food materials ready for immediate use can be
transferred from soil to plant. How this association influences the work
of the green leaf is one of the most interesting problems science has now
to investigate. Is the effective synthesis of carbohydrates and proteins
in the green leaf dependent on the digestion products of these soil
fungi? It is more than probable that this must prove to be the case. Are
these digestion products at the root of disease resistance and quality?
It would appear so. If this is the case it would follow that on the
efficiency of this mycorrhizal association the health and well-being of
mankind must depend.

In a fertile soil the soil and the plant come into gear in two ways
simultaneously. In establishing and maintaining these contacts humus is
essential. It is therefore a key material in the life cycle. Without this
substance the wheel of life cannot function effectively.

The processes of decay which round off and complete the wheel of life can
be seen in operation on the floor of any woodland. This has already been
discussed. It has been shown how the mixed animal and vegetable wastes
are converted into humus and how the forest manures itself.

Such are the essential facts in the wheel of life. Growth on the one
side: decay on the other. In Nature's farming a balance is struck and
maintained between these two complementary processes. The only man-made
systems of agriculture--those to be found in the East--which have stood
the test of time have faithfully copied this rule in Nature. It follows
therefore that the correct relation between the processes of growth and
the processes of decay is the first principle of successful farming.
Agriculture must always be balanced. If we speed up growth we must
accelerate decay. If, on the other hand, the soil's reserves are
squandered, crop production ceases to be good farming: it becomes
something very different. The farmer is transformed into a bandit.

It is now possible to define more clearly the meaning of soil fertility.
It is the condition of a soil rich in humus in which the growth processes
proceed rapidly, smoothly, and efficiently. The term therefore connotes
such things as abundance, high quality, and resistance to disease. A soil
which grows to perfection a wheat crop--the food of man--is described
fertile. A pasture on which meat and milk of the first class are produced
falls into the same category. An area under market-garden crops on which
vegetables of the highest quality are raised has reached the peak as
regards fertility.

Why does soil fertility so markedly influence the soil, the plant, and
the animal? By virtue of the humus it contains. The nature and properties
of this substance as well as the products of its decomposition are
therefore important. These matters must now be considered.

What is humus? A reply to this question has been rendered easier by the
appearance in 1938 of the second edition of Waksman's admirable monograph
on humus in which the results of no less than 1311 original papers have
been reduced to order. Waksman defines humus as


'a complex aggregate of brown to dark-coloured amorphous substances which
have originated during the decomposition of plant and animal residues by
micro-organisms, under aerobic and anaerobic conditions, usually in
soils, composts, peat bogs, and water basins. Chemically, humus consists
of various constituents of the original plant material resistant to
further decomposition; of substances undergoing decomposition; of
complexes resulting from decomposition either by processes of hydrolysis
or by oxidation and reduction; and of various compounds synthesized by
micro-organisms. Humus is a natural body; it is a composite entity, just
as are plant, animal, and microbial substances; it is even much more
complex chemically, since all these materials contribute to its
formation. Humus possesses certain specific physical, chemical, and
biological properties which make it distinct from other natural organic
bodies. Humus, in itself or by interaction with certain inorganic
constituents of the soil, forms a complex colloidal system, the different
constituents of which are held together by surface forces; this system is
adaptable to changing conditions of reaction, moisture, and action by
electrolytes. The numerous activities of the soil micro-organisms take
place in this system to a large extent.'


Viewed from the standpoint of chemistry and physics humus is therefore
not a simple substance: it is made up from a group of very complex
organic compounds depending on the nature of the residues from which it
is formed, on the conditions under which decomposition takes place, and
on the extent to which the processes of decay have proceeded. Humus,
therefore, cannot be exactly the same thing everywhere. It is bound to be
a creature of circumstance. Moreover it is alive and teems with a vast
range of micro-organisms which derive most of their nutriment from this
substratum. Humus in the natural state is dynamic, not static. From the
point of view of agriculture, therefore, we are dealing not with simple
dead matter like a sack of sulphate of ammonia, which can be analysed and
valued according to its chemical composition, but with a vast organic
complex in which an important section of the farmer's invisible labour
force--the organisms which carry on the work of the soil--is temporarily
housed. Humus, therefore, involves the element of labour; in this respect
also it is one of the most important factors on the farm.

It is essential at this point to pay some attention to the manysided
properties of humus and to realize how profoundly it differs from a
chemical manure. At the moment all over the world field trials--based on
mere nitrogen content--are in progress for comparing, on the current
crop, dressings of humus and various artificial manures. A mere glance at
the properties of humus will show that such field trials are based on a
fundamental misconception of what soil fertility implies and are
misleading and therefore useless.

The properties of humus have been summed up by Waksman as follows:

1. Humus possesses a dark brown to black colour.

2. Humus is practically insoluble in water, although a part of it may go
into colloidal solution in pure water. Humus dissolves to a large extent
in dilute alkali solutions, especially on boiling, giving a dark coloured
extract; a large part of this extract precipitates when the alkali
solution is neutralized by mineral acids.

3. Humus contains a somewhat larger amount of carbon than do plant,
animal, and microbial bodies; the carbon content of humus is usually
about 55 to 56 per cent., and frequently reaches 58 per cent.

'4. Humus contains considerable nitrogen, usually about 3 to 6 per cent.
The nitrogen concentration may be frequently less than this figure; in
the case of certain high-moor peats, for example, it may be only 0.5-0.8
per cent. It may also be higher, especially in sub-soils, frequently
reaching 10 to 12 per cent.

'5. Humus contains the elements carbon and nitrogen in proportions which
are close to 10:1; this is true of many soils and of humus in sea
bottoms. This ratio varies considerably with the nature of the humus, the
stage of its decomposition, the nature and depth of soil from which it is
obtained, the climatic and other environmental conditions under which it
is formed.

6. Humus is not in a static, but rather in a dynamic, condition, since it
is constantly formed from plant and animal residues and is continuously
decomposed further by micro-organisms.

7. Humus serves as a source of energy for the development of various
groups of micro-organisms, and during decomposition gives off a
continuous stream of carbon dioxide and ammonia.

8. Humus is characterized by a high capacity of base-exchange, of
combining with various other soil constituents, of absorbing water, and
of swelling, and by other physical and physico-chemical properties which
make it a highly valuable constituent of substrates which support plant
and animal life.'


To this list of properties must be added the role of humus as a cement in
creating and maintaining the compound soil particles so important in the
maintenance of tilth.

The effect of humus on the crop is nothing short of profound. The farmers
and peasants who live in close touch with Nature can tell by a glance at
the crop whether or not the soil is rich in humus. The habit of the plant
then develops something approaching personality; the foliage assumes a
characteristic set; the leaves acquire the glow of health; the flowers
develop depth of colour; the minute morphological characters of the whole
of the plant organs become clearer and sharper. Root development is
profuse: the active roots exhibit not only turgidity but bloom.

The influence of humus on the plant is not confined to the outward
appearance of the various organs. The quality of the produce is also
affected. Seeds are better developed, and so yield better crops and also
provide live stock with a satisfaction not conferred by the produce of
worn-out land. The animals need less food if it comes from fertile soil.
Vegetables and fruit grown on land rich in humus are always superior in
quality, taste, and keeping power to those raised by other means. The
quality of wines, other things being equal, follows the same rule. Almost
every villager in countries like France appreciates these points and will
talk of them freely without the slightest prompting.

In the case of fodder a very interesting example of the relation between
soil fertility and quality has recently been investigated. This was
noticed in the meadows of La Crau between Salon and Aries in Provence.
Here the fields are irrigated with muddy water, containing finely divided
limestone drawn from the Durance, and manured mostly with farm-yard
manure. The soils are open and permeable, the land is well drained
naturally. All the factors on which soil fertility depends are present
together--an open soil with ample organic matter, ample moisture, and the
ideal climate for growth. Any grazier who saw these meadows for the first
time would at once be impressed by them: a walk through the fields at
hay-making would prepare him for the news that it pays the owners of
high-quality animals to obtain their roughage from this distant source.
Several cuts of hay are produced every year, which enjoy such a
reputation for quality that the bales are sent long distances by motor
lorry to the various racing stables of France and are even exported to
Newmarket. The small stomach of the racehorse needs the very best food
possible. This the meadows of La Crau help to produce.

The origin of these irrigated meadows would provide an interesting story.
Did they arise as the result of a set of permanent manurial experiments
on the Broadbalk model or through the work of some observant local
pioneer? I suspect the second alternative will be found to be nearer the
truth. A definite answer to this question is desirable because in a
recent discussion at Rothamsted, on the relation between a fertile soil
and high-quality produce, it was stated that no evidence of such a
connexion could be discovered in the literature. The farmers of Provence,
however, have supplied it and also a measure of quality in the shape of a
satisfactory price. For the present the only way of measuring quality
seems to be by selling it. It cannot be weighed and measured by the
methods of the laboratory. Nevertheless it exists: moreover it
constitutes a very important factor in agriculture. Apparently some of
the experiment stations have not yet come to grips with this factor: the
farmers have. The sooner therefore that effective liaison is established
between these two agencies the better.

The effect of soil fertility on live stock can be observed in the field.
As animals live on crops we should naturally expect the character of the
plant as regards nutrition to be passed on to stock. This is so. The
effect of a fertile soil can at once be seen in the condition of the
animals. This is perhaps most easily observed in the bullocks fattened on
some of the notable pastures in Great Britain. The animals show a
well-developed bloom, the coat and skin look and feel right, the eyes are
clear, bright, and lively. The posture of the animal betokens health and
well-being. It is not necessary to weigh or measure them. A glance on the
part of a successful grazier, or of a butcher accustomed to deal with
high-class animals, is sufficient to tell them whether all is well or
whether there is something wrong with the soil or the management of the
animals or both. The results of a fertile soil and proper methods of
management are measured by the prices these animals fetch in the market
and the standing of the farmer in these markets. It should be a
compulsory item in the training of agricultural investigators to
accompany some of the best of our English cattle from the pasture to the
market and watch what happens there. They would at once discover that the
most fertile pastures produce the best animals, that auctioneers and
buyers detect quality instantly, and that such animals find a ready sale
and command the best prices. The reputation of the pastures is finally
passed on to the butcher and to his clients.

Resistance to insect and fungous disease is also conferred by humus.
Perhaps the best examples of this are to be seen in the East. In India,
the crops grown on the highly fertile soils round the 500,000 villages
suffer remarkably little from pests. This subject is developed at length
in a future chapter when the retreat of the crop and of the animal before
the parasite is discussed.

Soil fertility not only influences crops and live stock but also the
fauna of the locality. This is perhaps most easily seen in the fish of
streams which flow through areas of widely differing degrees of
fertility. An example of such difference is referred to at the end of
Chapter V of Isaac Walton's COMPLEAT ANGLER the following words:


'And so I shall proceed next to tell you, it is certain, that certain
fields near Leominster, a town in Herefordshire, are observed to make
sheep that graze upon them more fat than the next, and also to bear finer
wool; that is to say, that in that year in which they feed in such a
particular pasture, they shall yield finer wool than they did that year
before they came to feed in it, and coarser again if they shall return to
their former pasture; and again return to a finer wool, being fed in the
fine wool ground. Which I tell you, that you may the better believe that
I am certain, if I catch a trout in one meadow he shall be white and
faint, and very likely to be lousy; and as certainly if I catch a trout
in the next meadow, he shall be strong and red and lusty and much better
meat: trust me, scholar. I have caught many a trout in a particular
meadow, that the very shape and enamelled colour of him hath been such as
hath joyed me to look on him: and I have then with much pleasure
concluded with Solomon, "Everything is beautiful in his season".'


Soil fertility is the condition which results from the operation of
Nature's round, from the orderly revolution of the wheel of life, from
the adoption and faithful execution of the first principle of
agriculture--there must always be a perfect balance between the processes
of growth and the processes of decay. The consequences of this condition
are a living soil, abundant crops of good quality, and live stock which
possess the bloom of health. The key to a fertile soil and a prosperous
agriculture is humus.



BIBLIOGRAPHY

RAYNER, M. C. Mycorrhiza: an Account of Non-pathogenic Infection
by Fungi in Vascular Plants and Bryophytes, London, 1927.

---------'Mycorrhiza in relation to Forestry', Forestry, viii,
1934, p. 96; x, 1936, p. 1; and xiii, 1939, p. 19.

WAKSMAN, S. A. Humus: Origin, Chemical Composition, and Importance
in Nature, London, 1938.




CHAPTER III



THE RESTORATION OF FERTILITY


The moment mankind undertook the business of raising crops and breeding
animals, the processes of Nature were subjected to interference. Soil
fertility was exploited for the growing of food and the production of the
raw materials--such as wool, skins, and vegetable fibres--needed for
clothing. Up to the dawn of the Industrial Revolution in the West, the
losses of humus involved in these agricultural operations were made up
either by the return of waste material to the soil or by taking up virgin
land.

Where the return of wastes balanced the losses of humus involved in
production, systems of agriculture became stabilized and there was no
loss of fertility. The example of China has already been quoted. The old
mixed farming of a large part of Europe, including Great
Britain--characterized by a correct balance between arable and live
stock, the conversion of wastes into farmyard manure, methods of sheep
folding, and the copious use of the temporary ley--is another instance of
the same thing.

The constant exploitation of new areas to replace worn-out land has also
gone on for centuries and is still taking place. Sometimes this has
involved wars and conquests: at other times nothing more than taking up
fresh prairie or forest land wherever this was to be found. A special
method is adopted by some primitive tribes. The forest growth is burnt
down, the store of humus is converted into crops, the exhausted land is
given back to Nature for reafforestation and the building up of a new
reserve of humus. In a rough and ready way fertility is maintained. Such
shifting cultivation still exists all over the world, but like the taking
up of new land is only possible when the population is small and suitable
land abundant. This burning process has even been incorporated into
permanent systems of agriculture and has proved of great value in rice
cultivation in western India. Here the intractable soils of the rice
nurseries have to be prepared during the last part of the hot season so
that the seedlings are ready for transplanting by the break of the
monsoon. This is achieved by covering the nurseries with branches
collected from the forest and setting fire to the mass. The heat destroys
the colloids, restores the tilth, and makes the manuring and cultivation
of the rice nurseries possible.

It is an easy matter to destroy a balanced agriculture. Once the demand
for food and raw materials increases and good prices are obtained for the
produce of the soil, the pressure on soil fertility becomes intense. The
temptation to convert this fertility into money becomes irresistible.
Western agriculture was subjected to this strain by the very rapid
developments which followed the invention of the steam-engine, the
internal combustion engine, electrically driven motors, and improvements
in communications and transport. Factory after factory arose; a demand
for labour followed; the urban population increased. All these
developments provided new and expanding markets for food and raw
materials. These were supplied in three ways--by cashing-in the existing
fertility of the whole world, by the use of a temporary substitute for
soil fertility in the shape of artificial manures, and by a combination
of both methods. The net result has been that agriculture has become
unbalanced and therefore unstable.

Let us review briefly the operations of Western agriculture from the
point of view of the utilization of wastes in order to discover whether
the gap between the losses and gains of humus, now bridged by
artificials, can be reduced or abolished altogether. If this is possible,
something can be done to restore the balance of agriculture and to make
it more stable and therefore more permanent.

Many sources of soil organic matter exist, namely: (1) the roots of
crops, weeds, and crop residues which are turned under in the course of
cultivation; (2) the algae met with in the surface soil; (3) temporary
leys, the turf of worn-out grass land, catch crops, and green-manures;
(4) the urine of animals; (5) farmyard manure; (6) the contents of the
dustbins of our cities and towns; (7) certain factory wastes which result
from the processing of agricultural produce; (8) the wastes of the urban
population; (9) water-weeds, including seaweed. These must now be very
briefly considered. In later chapters most of these matters will be
referred to again and discussed in greater detail.

THE RESIDUES TURNED UNDER IN THE COURSE OF CULTIVATION. It is not always
realized that about half of every crop--the root system--remains in the
ground at harvest time and thus provides a continuous return of organic
matter to the soil. The weeds and their roots ploughed in during the
ordinary course of cultivation add to this supply. When these residues,
supplemented by the fixation of nitrogen from the atmosphere, are
accompanied by skilful soil management, which safeguards the precious
store of humus, crop production can be maintained at a low level without
the addition of any manure whatsoever beyond the occasional droppings of
live stock and birds. A good example of such a system of farming without
manure is to be found in the alluvial soils of the United Provinces in
India where the field records of ten centuries prove that the land
produces small crops year after year without any falling off in
fertility. A perfect balance has been reached between the manurial
requirements of the crops harvested and the natural processes which
recuperate fertility. The greatest care, however, is taken not to
over-cultivate, not to cultivate at the wrong time, or to stimulate the
soil processes by chemical manures. Systems of farming such as these
supply as it were the base-line for agricultural development. A similar
though not so convincing result is provided by the permanent wheat plot
at Rothamsted, where this crop has been grown on the same land without
manure since 1844. This plot, which has been without manure of any kind
since 1839, showed a slow decline in production for the first eighteen
years, after which the yield has been practically constant. The reserves
of humus in this case left over from the days of mixed farming evidently
lasted for nearly twenty years. There are, however, two obvious
weaknesses in this experiment. This plot does not represent any system of
agriculture, it only speaks for itself. Nothing has been done to prevent
earthworms and other animals from bringing in a constant supply of
manure, in the shape of their wastes, from the surrounding land. It is
much too small to yield a significant result.

Soil algae are a much more important factor in the tropics than in
temperate regions. Nevertheless they occur in all soils and often play a
part in the maintenance of soil fertility. Towards the end of the rainy
season in countries like India a thick algal film occurs on the surface
of the soil which immobilizes a large amount of combined nitrogen
otherwise likely to be lost by leaching. While this film is forming
cultivation is suspended and weeds are allowed to grow. Just before the
sowing of the cold weather crops in October the land is thoroughly
cultivated, when this easily decomposable and finely divided organic
matter, which is rich in nitrogen, is transformed into humus and then
into nitrates. How far a similar method can be utilized in colder
countries is a matter for investigation. In the East cultivation always
fits in with the life-cycle in a remarkable way. In the West cultivation
is regarded as an end in itself and not, as it should be, as a factor in
the wheel of life. Europe has much to learn from Asia in the cultivation
of the soil.

TEMPORARY LEYS, CATCH-CROPS, GREEN-MANURES, AND THE TURF OF WORN-OUT
GRASS LAND are perhaps the most important source of humus in Western
agriculture. All these crops develop a large root system; the permanent
and temporary leys give rise to ample residues of organic matter which
accumulate in the surface soil. Green-manures and catch-crops develop a
certain amount of soft and easily decomposable tissue. Provided these
crops are properly utilized a large addition of new humus can be added to
the soil. The efficiency of these methods of maintaining soil fertility
could, however, be very greatly increased.

THE URINE OF ANIMALS. The key substance in the manufacture of humus from
vegetable wastes is urine--the drainage of the active cells and glands of
the animal. It contains in a soluble and balanced form all the nitrogen
and minerals, and in all probability the accessory growth-substances as
well, needed for the work of the fungi and bacteria which break down the
various forms of cellulose--the first step in the synthesis of humus. It
carries in all probability every raw material, known and unknown,
discovered and undiscovered, needed in the building up of a fertile soil.
Much of this vital substance for restoring soil fertility is either
wasted or only imperfectly utilized. This fact alone would explain the
disintegration of the agriculture of the West.

Although FARM-YARD MANURE has always been one of the principal means of
replenishing soil losses, even now the methods by which this substance is
prepared are nothing short of deplorable. The making of farm-yard manure
is the weakest link in the agriculture of Western countries. For
centuries this weakness has been the fundamental fault of Western
farming, one completely overlooked by many observers and the great
majority of investigators.

DUSTBIN REFUSE. Practically no agricultural use is now being made of the
impure cellulose and kitchen wastes which find their way into the urban
dustbin. These are mostly buried in controlled tips or burnt.

ANIMAL RESIDUES. A number of wastes connected with the processing of food
and some of the raw materials needed in industry are utilized on the land
and find a ready market. The animal residues include such materials as
dried blood, feathers, greaves, hair waste, hoof and horn, rabbit waste,
slaughter-house refuse, and fish waste. There is a brisk demand for most
of these substances, as they give good results on the land. The only
drawback is the limited supplies available. The organic residues from
manufacture consist of damaged oil-cakes, shoddy and tannery waste, of
which shoddy, a by-product of the wool industry, is the most important.
These two classes of wastes, animal and industrial, are applied to the
soil direct and, generally speaking, command much higher prices than
would be expected from their content of nitrogen, phosphorus, and potash.
This is because the soil is in such urgent need of humus and because the
supply falls so far short of the demand. It is probable that a better use
for these wastes will be found as raw materials for the compost heaps of
the future, where they will act as substitutes for urine in the breaking
down of dustbin refuse in localities where the supply of farm-yard manure
is restricted.

WATER WEEDS. Little use is made of water weeds in maintaining soil
fertility. Perhaps the most useful of these is seaweed, which is thrown
up on the beaches in large quantities at certain times of the year and
which contains iodine and includes the animal residues needed for
converting vegetable wastes into humus. Many of our sea-side resorts
could easily manufacture from seaweed and dustbin refuse the vast
quantities of humus needed for the farms and market gardens in their
neighbourhood and so balance the local agriculture. Little or nothing,
however, is being done in this direction. In some cases the seaweed
collection on pleasure beaches is taken up by the farmers with good
results, but the systematic utilization of seaweed in the compost heap is
still a matter for the future. The streams and rivers which carry off the
surplus rainfall also contain appreciable quantities of combined nitrogen
and minerals in solution. Much of this could be intercepted by the
cultivation of suitable plants on the borders of these streams which
would furnish large quantities of easily decomposable material for humus
manufacture.

THE NIGHT SOIL AND URINE of the population is at present almost
completely lost to the land. In urban areas the concentration of the
population is the main reason why water-borne sewage systems have
developed. The greatest difficulty in the path of the reformer is the
absence of sufficient land for dealing with these wastes. In country
districts, however, there are no insurmountable obstacles to the
utilization of human wastes.

It will be evident that in almost every case the vegetable and animal
residues of Western agriculture are either being completely wasted or
else imperfectly utilized. A wide gap between the humus used up in crop
production and the humus added as manure has naturally developed. This
has been filled by chemical manures. The principle followed, based on the
Liebig tradition, is that any deficiencies in the soil solution can be
made up by the addition of suitable chemicals. This is based on a
complete misconception of plant nutrition. It is superficial and
fundamentally unsound. It takes no account of the life of the soil,
including the mycorrhizal association--the living fungous bridge which
connects soil and sap. Artificial manures lead inevitably to artificial
nutrition, artificial food, artificial animals, and finally to artificial
men and women.

The ease with which crops can be grown with chemicals has made the
correct utilization of wastes much more difficult. If a cheap substitute
for humus exists why not use it? The answer is twofold. In the first
place, chemicals can never be a substitute for humus because Nature has
ordained that the soil must live and the mycorrhizal association must be
an essential link in plant nutrition. In the second place, the use of
such a substitute cannot be cheap because soil fertility--one of the most
important assets of any country--is lost; because artificial plants,
artificial animals, and artificial men are unhealthy and can only be
protected from the parasites, whose duty it is to remove them, by means
of poison sprays, vaccines and serums and an expensive system of patent
medicines, panel doctors, hospitals, and so forth. When the finance of
crop production is considered together with that of the various social
services which are needed to repair the consequences of an unsound
agriculture, and when it is borne in mind that our greatest possession is
a healthy, virile population, the cheapness of artificial manures
disappears altogether. In the years to come chemical manures will be
considered as one of the greatest follies of the industrial epoch. The
teachings of the agricultural economists of this period will be dismissed
as superficial.

In the next section of this book the methods by which the agriculture of
the West can be reformed and balanced and the use of artificial manures
given up will be discussed.



BIBLIOGRAPHY

CLARKE, G. 'Some Aspects of Soil Improvement in relation to Crop
Production' Proc. of the Seventeenth Indian Science Congress,
Asiatic Society of Bengal, Calcutta, 1930, p. 23

HALL, SIR A. DANIEL. The Improvement of Native Agriculture in relation to
Population and Public Health, Oxford University Press, 1936.

HOWARD, A., and WAD, Y. D. The Waste Products of Agriculture:
Their Utilization as Humus, Oxford University Press, 1931

MANN, H. H., JOSHI, N. V., and KANITICAR, N. V. 'The Rab System of Rice
Cultivation in Western India', Mem. of the Dept. of Agriculture in India
(Chemical Series), ii 1912, p. 141.

Manures and Manuring, Bulletin 36 of the Ministry of Agriculture
and Fisheries, H.M. Stationery Office, 1937.





PART II  THE INDORE PROCESS




CHAPTER IV



THE INDORE PROCESS


The Indore Process for the manufacture of humus from vegetable and animal
wastes was devised at the Institute of Plant Industry, Indore, Central
India, between the years 1924 and 1931. It was named after the Indian
State in which it originated, in grateful remembrance of all the Indore
Darbar did to make my task in Central India easier and more pleasant.

Although the working out of the actual process only took seven years, the
foundations on which it is based occupied me for more than a quarter of a
century. Two independent lines of thought and study led up to the final
result. One of these concerns the nature of disease and is discussed more
fully in Chapter XI under the heading--'The Retreat of the Crop and the
Animal before the Parasite'. It was observed in the course of these
studies that the maintenance of soil fertility is the real basis of
health and of resistance to disease. The various parasites were found to
be only secondary matters: their activities resulted from the breakdown
of a complex biological system--the soil in its relation to the plant and
to the animal--due to improper methods of agriculture, an impoverished
soil, or to a combination of both.

The second line of thought arose in the course of nineteen years
(1905-24) spent in plant-breeding at Pusa, when it was gradually realized
that the full possibilities of the improvement of the variety can only be
achieved when the soil in which the new types are grown is provided with
an adequate supply of humus. Improved varieties by themselves could be
relied upon to give an increased yield in the neighbourhood of 10 per
cent.: improved varieties plus better soil conditions were found to
produce an increment up to 100 per cent. or even more. As an addition of
even 10 per cent. to the yield would ultimately impose a severe strain on
the frail fertility reserves of the soils of India and would gradually
lead to their impoverishment, plant-breeding to achieve any permanent
success would have to include a continuous addition to the humus content
of the small fields of the Indian cultivators. The real problem was not
the improvement of the variety but how simultaneously to make the variety
and the soil more efficient.

By about the year 1918 these two hitherto independent approaches to the
problems of crop production--by way of pathology and by way of
plant-breeding--began to coalesce. It became clearer and clearer that
agricultural research itself was involved in the problem; that the
organization was responsible for the failure to recognize the things that
matter in agriculture and would therefore have to be reformed; the
separation of work on crops into such compartments as plant-breeding,
mycology, entomology, and so forth, would have to be given up; the plant
would have to be studied in relation to the soil on the one hand and to
the agricultural practices of the locality on the other. An approach to
the problems of crop production on such a wide front was obviously
impossible in a research institute like Pusa in which the work on crops
was divided into no less than six separate sections. The working out of a
method of manufacturing humus from waste products and a study of the
reaction of the crop to improved soil conditions would encroach on the
work of practically every section of the Institute. As no progress has
ever been made in science without complete freedom, the only way of
studying soil fertility as one subject appeared to be to found a new
institute in which the plant would be the centre of the subject and where
science and practice could be brought to bear on the problem without any
consideration of the existing organization of agricultural research.
Thanks to the support of a group of Central Indian States and a large
grant from the Indian Central Cotton Committee, the Institute of Plant
Industry was founded at Indore in 1924. Central India was selected as the
home of this new research centre for two reasons: (1) the offer on a 99
years' lease of an area of 300 acres of suitable land by the Indore
Darbar, and (2) the absence in the Central India Agency of any organized
system of agricultural research such as had been established throughout
British India. This tract therefore provided the land on the one hand and
freedom from interference on the other for the working out of a new
approach, based on the humus content of the soil, to the problems
underlying crop production. (An account of the organization of the
Institute of Plant Industry was published as THE APPLICATION OF SCIENCE
TO CROP-PRODUCTION by the Oxford University Press in 1929.)

The work at Indore accomplished two things: (1) the obsolete character of
the present-day organization of agricultural research was demonstrated;
(2) a practical method of manufacturing humus was devised.

The Indore Process was first described in detail in 1931 in Chapter IV of
THE WASTE PRODUCTS OF AGRICULTURE. Since that date the method has been
taken up by most of the plantation industries and also on many farms and
gardens all over the world. In the course of this work nothing has been
added to the two main principles underlying the process, namely, (1) the
admixture of vegetable and animal wastes with a base for neutralizing
acidity, and (2) the management of the mass so that the micro-organisms
which do the work can function in the most effective manner. A number of
minor changes in working have, however, been suggested. Some of these
have proved advantageous in increasing the output. In the following
account the original description has been followed, but all useful
improvements have been incorporated: the technique has been brought up to
date.


THE RAW MATERIALS NEEDED

1. VEGETABLE WASTES. In temperate countries like Great Britain these
include--straw, chaff, damaged hay and clover, hedge and bank trimmings,
weeds including sea-and water-weeds, prunings, hop-vine and hop-string,
potato haulm, market-garden residues including those of the greenhouse,
bracken, fallen leaves, sawdust, and wood shavings. A limited amount of
other vegetable material like the husks of cotton seed, cacao, and ground
nuts as well as banana stalks are also available near some of the large
cities.

In the tropics and sub-tropics the vegetable wastes consist of very
similar materials including the vegetation of waste areas, grass, plants
grown for shade and green-manure, sugar-cane leaves and stumps, all crop
residues not consumed by live stock, cotton stalks, weeds, sawdust and
wood shavings, and plants grown for providing compostable material on the
borders of fields, roadsides, and any vacant corners available.

A continuous supply of mixed dry vegetable wastes throughout the year, in
a proper state of division, is the chief factor in the process. The ideal
chemical composition of these materials should be such that, after being
used as bedding for live stock, the carbon: nitrogen ratio is in the
neighbourhood of 33:1. The material should also be in such a physical
condition that the fungi and bacteria can obtain ready access to and
break down the tissues without delay. The bark, which is the natural
protection of the celluloses and lignins against the inroads of fungi,
must first be destroyed. This is the reason why all woody materials--such
as cotton and pigeon-pea stalks--were always laid on the roads at Indore
and crushed by the traffic into a fine state of division before
composting.

All over the world one of the first objections to the adoption of the
Indore Process is that there is nothing worth composting or only small
supplies of such material. In practically all such cases any shortage of
wastes has soon been met by a more effective use of the land and by
actually growing plants for composting on every possible square foot of
soil. If Nature's way of using sunlight to the full in the virgin forest
is compared with that on the average farm or on the average tea and
rubber estate, it will be seen what leeway can be made up in growing
suitable material for making humus. Sometimes the objection is heard that
all this will cost too much. The answer is provided by the dust-bowls of
North America. The soil must have its manurial rights or farming dies.

2. ANIMAL RESIDUES. The animal residues ordinarily available all over the
world are much the same--the urine and dung of live stock, the droppings
of poultry, kitchen waste including bones. Where no live stock is kept
and animal residues are not available, substitutes such as dried blood,
slaughter-house refuse, powdered hoof and horn, fish manure, and so forth
can be employed. The waste products of the animal in some form or another
are essential if real humus is to be made for the two following reasons.

(a) The verdict given by mother earth between humus made with animal
residues and humus made with chemical activators like calcium cyanamide
and the various salts of ammonia has always been in favour of the former.
One has only to feel and smell a handful of compost made by these two
methods to understand the plant's preference for humus made with animal
residues. The one is soft to the feel with the smell of rich woodland
earth: the other is often harsh to the touch with a sour odour. Sometimes
when the two samples of humus made from similar vegetable wastes are
analysed, the better report is obtained by the compost made with chemical
activators. When, however, they are applied to the soil the plant
speedily reverses the verdict of the laboratory. Dr. Rayner refers to
this conflict between mother earth and the analyst, in the case of some
composts suitable for forestry nurseries, in the following words:


'Full chemical analyses are now available for a number of these composts,
and it is not without interest to recall that in the initial stages of
the work a competent critic reported on one of them--since proved to be
among the most effective a basis of comparative analysis, as "an organic
manure of comparatively little value"; while another--since proved least
successful of all those tested--was approved as a "first-class organic
manure".'


The activator used in the first case was dried blood, in the second case
an ammonium salt.

(b) No permanent or effective system of agriculture has ever been devised
without the animal. Many attempts have been made, but sooner or later
they break down. The replacement of live stock by artificials is always
followed by disease the moment the original store of soil fertility is
exhausted.

Where live stock is maintained the collection of their waste
products--urine and dung--in the most effective manner is important.

At Indore the work-cattle were kept in well-ventilated sheds with earthen
floors and were bedded down daily with mixed vegetable wastes including
about 5 per cent. by volume of hard resistant material such as wood
shavings and sawdust. The cattle slept on this bedding during the night
when it was still further broken up and impregnated with urine. Next
morning the soiled bedding and cattle dung were removed to the pits for
composting; the earthen floor was then swept clean and all wet places
were covered with new earth, after scraping out the very wet patches. In
this way all the urine of the animals was absorbed; all smell in the
cattle sheds was avoided, and the breeding of flies in the earth
underneath the animals was entirely prevented. A new layer of bedding for
the next day was then laid.

Every three months the earth under the cattle was changed, the
urine-impregnated soil was broken up in a mortar mill and stored under
cover near the compost pits. This urine earth, mixed with any wood ashes
available, served as a combined activator and base in composting.

In the tropics, where there is abundance of labour, no difficulty will be
experienced in copying the Indore plan. All the urine can be absorbed:
all the soiled bedding can be used in the compost pits every morning.

In countries like Great Britain and North America, where labour is both
scarce and dear, objection will at once be raised to the Indore plan.
Concrete or pitched floors are here the rule. The valuable urine and dung
are often removed to the drains by a water spray. In such cases, however,
the indispensable urine could either be absorbed on the floors themselves
by the addition to the bedding of substances like peat and sawdust mixed
with a little earth, or the urine could be directed into small bricked
pits just outside the building, filled with any suitable absorbent which
is periodically removed and renewed. In this way liquid manure tanks can
be avoided. At all costs the urine must be used for composting.

3. BASES FOR NEUTRALIZING EXCESSIVE ACIDITY. In the manufacture of humus
the fermenting mixture soon becomes acid in reaction. This acidity must
be neutralized, otherwise the work of the microorganisms cannot proceed
at the requisite speed. A base is therefore necessary. Where the
carbonates of calcium or potassium are available in the form of powdered
chalk or limestone, or wood ashes, these materials either alone,
together, or mixed with earth, provide a convenient base for maintaining
the general reaction within the optimum range (pH 7.0 to 8.0) needed by
the microorganisms which break down cellulose. Where wood ashes,
limestone, or chalk are not available, earth can be used by itself.
Slaked lime can also be employed, but it is not so suitable as the
carbonate. Quicklime is much too fierce a base.

4. WATER AND AIR. Water is needed during the whole of the period during
which humus is being made. Abundant aeration is also essential during the
early stages. If too much water is used the aeration of the mass is
impeded, the fermentation stops and may soon become anaerobic too soon.
If too little water is employed the activities of the micro-organisms
slow down and then cease. The ideal condition is for the moisture content
of the mass to be maintained at about half saturation during the early
stages, as near as possible to the condition of a pressed-out sponge.
Simple as all this sounds, it is by no means easy in practice
simultaneously to maintain the moisture content and the aeration of a
compost heap so that the micro-organisms can carry out their work
effectively. The tendency almost everywhere is to get the mass too
sodden.

The simplest and most effective method of providing water and oxygen
together is whenever possible to use the rainfall--which is a saturated
solution of oxygen--and always to keep the fermenting mass open at the
beginning so that atmospheric air can enter and the carbon dioxide
produced can escape.

After the preliminary fungous stage is completed and the vegetable wastes
have broken down sufficiently to be dealt with by bacteria, the synthesis
of humus proceeds under anaerobic conditions when no special measures for
the aeration of the dense mass are either possible or necessary.


PITS VERSUS HEAPS

Two methods of converting the above wastes into humus are in common use.
Pits or heaps can be employed.

Where the fermenting mass is liable to dry out or to cool very rapidly,
the manufacture should take place in shallow pits. A considerable saving
of water then results. The temperature of the mass tends to remain high
and uniform. Sometimes, however, composting in pits is disadvantageous on
account of water-logging by storm water, by heavy rain, and by the rise
of the ground-water from below. All these result in a wet sodden mass in
which an adequate supply of air is out of the question. To obviate such
water-logging the composting pits are: (1) surrounded by a catch-drain to
cut off surface water; (2) protected by a thatched roof where the
rainfall is high and heavy bursts of monsoon rain are the rule; or (3)
provided with soakaways at suitable points combined with a slight slope
of the floors of the pit towards the drainage corner. Where there is a
pronounced rise in the water-table during the rainy season, care must be
taken, in siting the pits, that they are so placed that there is no
invasion of water from below.

To save the expense of digging pits and to use up sites where excavation
is out of the question, composting in heaps is practiced. A great deal
can be done to increase the efficiency of the heap by protecting the
composting area from storm water by means of catch-drains and by suitable
shelter from wind, which often prevents all fermentation on the more
exposed sides of the heap. In temperate climates heaps should always face
the south, and wherever possible should be made in front of a south wall
and be protected from wind on the east and west. The effect of heavy rain
in slowing down fermentation can be reduced by increasing the size of the
heap as much as possible. Large heaps always do better than small ones.

In localities of high monsoon rainfall like Assam and Ceylon, there is a
definite tendency to provide the heap or the pit with a grass roof so
that the fermentation can proceed at an even rate and so that the annual
output is not interfered with by temporary water-logging. After a year or
two of service the roof itself is composted. In Great Britain thatched
hurdles can be used.


CHARGING THE HEAPS OR PITS

A convenient size for the compost pits (where the annual output is in the
neighbourhood of 1,000 tons) is 30 feet by 14 feet and 3 feet deep with
sloping sides. The depth is the most important dimension on account of
the aeration factor. Air percolates the fermenting mass to a depth of
about 18 to 24 inches only, so for a height of 36 inches extra aeration
must be provided. This is arranged by means of vertical vents, every 4
feet, made by a light crowbar as each section of the pit is charged.

Charging a pit 30 feet long takes place in six sections each 5 feet wide.
The first section, however, is left vacant to allow of the contents being
turned. The second section is first charged. A layer of vegetable wastes
about 6 inches deep is laid across the pit to a width of 5 feet. This is
followed by a layer of soiled bedding or farm-yard manure 2 inches in
thickness. The layer of manure is then well sprinkled with a mixture of
urine earth and wood ashes or with earth alone, care being taken not to
add more than a thin film of about one-eighth of an inch in thickness. If
too much is added aeration will be impeded. The sandwich is then watered
where necessary with a hose fitted with a rose for breaking up the spray.
The charging and watering process is then continued as before until the
total height of the section reaches 5 feet. Three vertical aeration
vents, about 4 inches in diameter, are then made in the mass by working a
crowbar from side to side. The first vent is in the centre, the other two
midway between the centre and the sides. As the pit is 14 feet wide and
there are three vents, these will be 3 feet 6 inches apart. The next
section of the pit (5 feet wide) is then built up close to the first and
watered as before. When five sections are completed the pit is filled.
The advantages of filling a pit or making a heap in sections to the full
height of 5 feet are: (1) fermentation begins at once in each section and
no time is lost; (2) no trampling of the mass takes place; (3) aeration
vents can be made in each completed section without standing on the
mixture.

In dry climates each day's contribution to the pit should again be
lightly watered in the evening and the watering repeated the next
morning. In this way the first watering at the time of charge is added in
three portions--one at the actual time of charging, in the evening after
charging is completed and again the next morning after an interval of
twelve hours. The object of this procedure is to give the mass the
necessary time to absorb the water.

The total amount of water that should be added at the beginning of
fermentation depends on the nature of the material, on the climate and on
the rainfall. Watering as a rule is unnecessary in Great Britain. If the
material contains about a quarter by volume of fresh greenstuff the
amount of water needed can be considerably reduced. In rainy weather when
everything is on the damp side no water at all is needed. Correct
watering is a matter of local circumstances and of individual judgement.
At no period should the mass be wet: at no period should the pit be
allowed to dry out completely. At the Iceni Nurseries in South
Lincolnshire in Great Britain, where the annual rainfall is about 24
inches and a good deal of fresh green market-garden refuse is composted,
watering the heaps at all stages is unnecessary. At Indore in Central
India where the rainfall was about 50 inches, which fell in about four
months, watering was always essential except during the actual rainy
season. These two examples prove that no general rule can ever be laid
down as to the amount of water to be added in composting. The amount
depends on circumstances. The water needed at Indore was from 200 to 300
gallons for each cubic yard of finished humus.

As each section of the pit is completed, everything is ready for the
development of an active fungous growth, the first stage in the
manufacture of humus. It is essential to initiate this growth as quickly
as possible and then to maintain it. As a rule it is well established by
the second or third day after charging. Soon after the first appearance
of fungous growth the mass begins to shrink and in a few days will just
fill the pit, the depth being reduced to about 36 inches.

Two things must be carefully watched for and prevented during the first
phase: (1) the establishment of anaerobic conditions caused generally by
over-watering or by want of attention to the details of charging; it is
at once indicated by smell and by the appearance of flies attempting to
breed in the mass; when this occurs the pit should be turned at once; (2)
fermentation may slow down for want of water. In such cases the mass
should be watered. Experience will soon teach what amount of water is
needed at the time of charge.


TURNING THE COMPOST

To ensure uniform mixture and decay and to provide the necessary amount
of water and air for the completion of the aerobic phase it is necessary
to turn the material twice.

FIRST TURN. The first turn should take place between 2 and 3 weeks after
charging. The vacant space, about 5 feet wide, at the end of the pit
allows the mass to be conveniently turned from one end by means of a
pitchfork. The fermenting material is piled up loosely against the vacant
end of the pit, care being taken to turn the unaltered layer in contact
with the air into the middle of the new heap. As the turning takes place,
the mass is watered, if necessary, as at the time of charging, care being
taken to make the material moist but not sodden with water. The aim
should be to provide the mass with sufficient moisture to carry on the
fermentation to the second turn. To achieve this sufficient time must be
given for the absorption of water. The best way is to proceed as at the
time of charging and add any water needed in two stages--as the turning
is being done and again next morning. Another series of vertical air
vents 3 feet 6 inches apart should be made with a crowbar as the new heap
is being made.

SECOND TURN. About five weeks after charge the material is turned a
second time but in the reverse direction. By this time the fungous stage
will be almost over, the mass will be darkening in colour and the
material will be showing marked signs of breaking down. From now onwards
bacteria take an increasing share in humus manufacture and the process
becomes anaerobic. The second turn is a convenient opportunity for
supplying sufficient water for completing the fermentation. This should
be added during the actual turning and again the next morning to bring
the moisture content to the ideal condition--that of a pressed-out
sponge. It will be observed as manufacture proceeds that the mass
crumbles and that less and less difficulty occurs in keeping the material
moist. This is due to two things: (1) less water is needed in the
fermentation; (2) the absorptive and water-holding power of the mass
rapidly increase as the stage of finished humus is approached.

Soon after the second turn the ripening process begins. It is during this
period that the fixation of atmospheric nitrogen takes place. Under
favourable circumstances as much as 25 per cent. Of additional free
nitrogen may be secured from the atmosphere.

The activity of the various micro-organisms which synthesize humus can
most easily be followed from the temperature records. A very high
temperature, about 65 degrees C. (149 degrees F.), is established at the
outset, which continues with a moderate downward gradient to 30 degrees
C. (86 degrees F.) at the end of ninety days. This range fits in well
with the optimum temperature conditions required for the micro-organisms
which break down cellulose. The aerobic thermophyllic bacteria thrive best
between 40 degrees C. (104  degrees F.) and 55 degrees C.
(131 degrees F.). Before each turn, a definite slowing down in the
fermentation takes place: this is accompanied by a fall in temperature.

As soon as the mass is re-made, when more thorough admixture with copious
aeration occurs, there is a renewal of activity during which the
undecomposed portion of the vegetable matter from the outside of the heap
or pit is attacked. This activity is followed by a distinct rise in
temperature.


THE STORAGE OF HUMUS

Three months after charge the micro-organisms will have fulfilled their
task and humus will have been completely synthesized. It is now ready for
the land. If kept in heaps after ripening is completed, a loss in
efficiency must be faced. The oxidation processes will continue.
Nitrification will begin, resulting in the formation of soluble nitrates.
These may be lost either by leaching during heavy rain or they will
furnish the anaerobic organisms with just the material they need for
their oxygen supply. Such losses do not occur to anything like the same
extent when the humus is banked by adding it to the soil. Freshly
prepared humus is perhaps the farmer's chief asset and must therefore be
looked after as if it were actual money. It is also an important section
of the live stock of the farm. Although this live stock can only be seen
under the microscope, it requires just as much thought and care as the
pigs which can be seen with the naked eye. If humus must be stored it
should be kept under cover and turned from time to time.


OUTPUT

The output of compost per annum obviously depends on circumstances. At
the Institute of Plant Industry, Indore, where the supply of urine and
dung was always greater than that of vegetable waste, fifty cartloads
(each 27 c. ft.) of ripe compost, i.e. 1,350 cubic feet or 50 cubic
yards, could be prepared from one pair of oxen. Had sufficient vegetable
wastes been available the quantity could have been at least doubled. The
work-cattle at Indore were of the Malvi breed, about three-quarters the
size of the average milking-cow of countries like Great Britain. The
urine and dung of an average English cow or bullock, therefore, if
properly composted with ample wastes would produce about sixty cartloads
of humus a year, equivalent to about 1,600 cubic feet or 60 cubic yards.

As the moisture content of humus varies from 30 to 60 per cent. during
the year, it is impossible to record the output in tons unless the
percentage of water is determined. The difficulty can be overcome by
expressing the output in cubic feet or cubic yards. The rate of
application per acre should also be stated as so many cubic feet or cubic
yards.

In devising the Indore Process the fullest use was made of agricultural
experience including that of the past. After the methods of Nature, as
seen in the forest, the practices which throw most light on the
preparation of humus are those of the Orient, which have been described
by King in FARMERS OF FORTY CENTURIES. In China a nation of observant
peasants has worked out for itself simple methods of returning to the
soil all the vegetable, animal, and human wastes that are available: a
dense population has been maintained without any falling off in
fertility.

Coming to the more purely laboratory investigations on the production of
humus, two proved of great value in perfecting the Indore Process: (1)
the papers of Waksman in which the supreme importance of micro-organisms
in the formation of humus was consistently stressed, and (2) the work of
H. B. Hutchinson and E. H. Richards on artificial farm-yard manure.
Waksman's insistence on the role of micro-organisms in the formation of
humus as well as on the paramount importance of the correct composition
of the wastes to be converted has done much to lift the subject from a
morass of chemical detail and empiricism on to the broad plane of biology
to which it rightly belongs. Once it was realized that composting
depended on the work of fungi and bacteria, the reform of the various
composting systems which are to be found all over the world could be
taken in hand. The essence of humus manufacture is first to provide the
organisms with the correct raw material and then to ensure that they have
suitable working conditions. Hutchinson and Richards come nearest to the
Indore Process but two fatal mistakes were made: (1) the use of chemicals
instead of urine as an activator in breaking down vegetable wastes, and
(2) the patenting of the ADCO process. Urine consists of the drainage of
every cell and every gland of the animal body and contains not only the
nitrogen and minerals needed by the fungi and bacteria which break down
cellulose, but all the accessory growth substances as well. The ADCO
powders merely supply factory-made chemicals as well as lime--a far
inferior base to the wood ashes and soil used in the Indore Process. It
focuses attention on yield rather than on quality. It introduces into
composting the same fundamental mistake that is being made in farming,
namely, the use of chemicals instead of natural manure. Further, the
patenting of a process (even when, as in this case, the patentees derive
no personal profit) always places the investigator in bondage; he becomes
the slave to his own scheme; rigidity takes the place of flexibility;
progress then becomes difficult, or even impossible. The ADCO process was
patented in 1916: in 1940 the method to all intents and purposes remains
unchanged.

The test of any process for converting the waste products of agriculture
into humus is flexibility and adaptability to every possible set of
conditions. It should also develop and be capable of absorbing new
knowledge and fresh points of view as they arise. Finally, it should be
suggestive and indicate new and promising lines of research. If the
Indore Process can pass these severe tests it will soon become woven into
the fabric of agricultural practice. It will then have achieved
permanence and will have furfilled its purpose--the restitution of their
manurial rights to the soils of this planet. In the next four chapters
the progress made during the last eight years towards this ideal will be
described.



BIBLIOGRAPHY

HOWARD, A., and HOWARD, G. L. C. The Application of Science to
Crop-Production, Oxford University Press, 1929.

HOWARD, A., and WAD, Y. D. The Waste Products of Agriculture:
Their Utilization as Humus, Oxford University Press, 1931.




CHAPTER V



PRACTICAL APPLICATIONS OF THE INDORE PROCESS


After the first complete account of the Indore Process was published in
1931, the adoption of the method at a number of centres followed very
quickly. The first results were summarized in a lecture which appeared in
the issue of the Journal of the Royal Society of Arts of December 8th,
1933. About 2,000 extra copies of this lecture were printed and
distributed during the next two years. By the end of 1935 it became
evident that the method was making very rapid headway all over the world:
an increasing stream of interesting results were reported. These were
described in a second lecture on November 13th, 1935, which was printed
in the Journal of the Society of November 22nd, 1935. This lecture was
then re-published in pamphlet form. In all 6,425 extra copies of this
second lecture have been distributed. During 1936 still further progress
was made, a brief account of which appeared in the Journal of the Royal
Society of Arts of December 18th, 1936; 7,500 copies being printed. Two
translations of the 1935 lecture have been published. The first in German
in Der Iropenpflanzer of February 1936, the second in Spanish in the
Revista del Instituto de Defensa del Cafe de Costa Rica of March 1937.

These papers did much to make the Indore Process known all over the world
and to start a number of new and active composting centres. The position,
as reached by July 1938, was briefly sketched in a paper which was
published in the Journal of the Ministry of Agriculture of Great Britain
of August 1938.

In this and succeeding chapters an attempt will be made to sum up
progress to the time of going to press. It will be convenient in the
first place to arrange this information under crops.


COFFEE

The first centre in Africa to take up the process was the Kingatori
Estate near Kyambu, a few miles from Nairobi, where work began in
February 1933. By the purest accident I saw the first beginnings of
composting at this estate. This occurred in the course of a tour round
Africa which included a visit to the Great Rift Valley. As I was about to
start from Nairobi on this expedition, Major Belcher, the Manager of
Kingatori, called upon me and said that he had just been instructed by
Major Grogan, the proprietor of the Estate, to start the Indore Process
and to convert all possible wastes into humus. He asked me to help him
and to discuss various practical details on the spot. I gave up the tour
to the Great Rift Valley and spent the day on the Kingatori Estate
instead, where it was obvious from the general condition of the bushes
and the texture of the soil that a continuous supply of freshly made
humus would transforn this estate, which I was told was representative of
the coffee industry near Nairobi. In a letter dated September 19th, 1933,
Major Belcher reported his first results as follows:

'I have 30 pits in regular use now, and am averaging 5 tons of ripe
compost from each pit. This will give me a  dressing of 3-1/2 tons per
acre per annum and should, I think, gradually bring the soil into really
good condition.

'I have already dressed 30 acres, but it is a little early to see any
result. It is 30 acres of young 4-year old coffee bearing a heavy crop.
At the moment it is looking splendid, and if it keeps it up until the
crop is picked in December and enables the trees to bear heavily again
next year there will be no doubt in my mind that the compost is
responsible. Young trees with a big crop are very apt to suffer from
die-back of the primaries and light beans and no crop in the following
year. There is no sign of this at present.

'I have had many interested visitors, and the Nairobi bookseller has to
keep sending for more copies of The  Waste Products of Agriculture.

'The District Commissioner at Embu has taken up the process extensively
with the double purpose of improving village sanitation and the fertility
of the soil. In fact, he started it some time before we did.

'I understand that it will shortly be made illegal to export goat and
cattle manure from the native reserves, in which case your process will
be taken up by most of the European farmers in the Colony. One very
influential member of the coffee industry remarked to me that he thought
your process would revolutionize coffee-growing and another said that he
considered it was the biggest step forward made in the last ten years.'


Two years later he sent me a second report in which he stated that during
the last 28 months 1,660 tons of compost, containing, about 1.5 per cent.
of nitrogen, had been manufactured on this estate and applied to the
land. The cost per ton was 4s. 4d.--chiefly the expense involved in
collecting raw material. The work in progress had been shown to a
constant stream of visitors from other parts of Kenya, the Rhodesias,
Uganda, Tanganyika, and the Belgian Congo. Major Belcher has lost count
of the actual numbers.

This pioneering work has done much more than weld the Indore Process into
the routine work of the estate. It has served the purpose of an
experiment station and a demonstration area for the coffee industry
throughout the world. Many new centres followed Kingatori. The rapid
spread of the method is summed up by Major Grogan in a letter dated
Nairobi, May 15th, 1935, as follows:

'You will be glad to know that your process is spreading rapidly in these
parts and has now become recognized routine practice on most of the well
conducted coffee plantations. The cumulative effect of two years on my
plantation is wonderful. I have now established all round my pits a large
area of elephant grass for the purpose of providing bulk, and we have
made quite a lot of pocket-money by selling elephant grass cuttings to
the country-side. I am now searching for the best indigenous legumes to
grow in conjunction with the elephant grass and am getting very hopeful
results from the various Crotaleries and Tephrosies which I have brought
up from the desert areas of Taveta. They get away quickly and so hold
their own against the local weeds.'


Major Grogan in referring to the spread of the Indore Process in East
Africa, has omitted one very material factor, namely, his personal share
in this result. He initiated the earliest trial on the Kingatori Estate
and has always insisted on the method having a square deal in Kenya. In
Tanganyika the influence of Sir Milsom Rees, G.C.V.O., has led to similar
results.

This example of the introduction and spread of the Indore Process on the
coffee estates of Kenya and Tanganyika has been given in detail for three
reasons: (1) it was one of the earliest applications of the Indore method
to the plantation industries; (2) it is typical of many other similar
applications elsewhere; and (3) it first suggested to me a new field of
work during retirement in which the research experience of a lifetime
could be fully utilized.

Kenya and Tanganyika are only two of the coffee centres of the world. The
largest producer is the New World. Here satisfactory progress has been
made following the publication in the West India Committee Circular of
April 23rd, 1936, of a short account of the Indore Process. This led to
important developments, first in Costa Rica and then in Central and South
America, as a result of a Spanish translation by Senor Don Mariano
Montealegre of my 1935 lecture to the Royal Society of Arts to which
reference has already been made. This was widely read in all parts of
Latin America: the lecture drew attention to the vital necessity of
organic matter in the production of coffee in the New World. During the
next two years no less than seven Spanish translations of my papers on
humus were published in the Revista del Instituto de Defensa del Cafe de
Costa Rica. In January 1939 a special issue of the Revista entitled En
Busca del Humus (In Quest of Humus) appeared. This was devoted to a
collection of papers describing the Indore Process and the various
developments of the last eight years.

The marked response of coffee to humus in Africa, India, and the New
World suggested that the crop would prove to be a mycorrhiza-former. A
number of samples of the surface roots of coffee plants were duly
collected in Travancore, Tanganyika, and Costa Rica and sent home for
examination. In all cases they showed the mycorrhizal association.


TEA

The East African results with coffee naturally suggested that something
should be done with regard to tea--a highly organized plantation industry
with the majority of the estates arranged in large groups, controlled by
a small London Directorate largely recruited from the industry itself.
The problem was how best to approach such an organization. In 1934 my
knowledge of tea and of the tea industry was of the slightest: I had
never grown a tea plant, let alone managed a tea plantation. I had only
visited two tea estates, one near Nuwara Eliya in Ceylon in 1908 and the
other near Dehra Dun in 1918. I had, however, kept in touch with the
research work on tea. While I was debating this question Providence came
to my assistance in the shape of a request from a mutual friend to help
Dr. C. R. Harler (who had just been retrenched when the Tocklai Research
Station, maintained by the Indian Tea Association, was reorganized in
1933) to find a new and better opening, if possible one with more scope
for independent and original work. I renewed my acquaintance with Dr.
Harler and suggested he should take up the conversion into humus of the
waste products of tea estates. He was very interested and shortly
afterwards (August 1933) accepted the post of Scientific Officer to the
Kanan Devan Hills Produce Co. in the High Range, Tray encore, which was
offered him by Messrs. James Finlay & Co., Ltd. On taking up his duties in
this well-managed and highly efficient undertaking, Dr. Harler secured
the active interest of the then General Manager, Mr. T. Wallace, and set
to work to try out the Indore Process on an estate scale at his
head-quarters at Nullatanni, near Munnar. No difficulties were met with
in working the method: ample supplies of vegetable wastes and cattle
manure were available: the local labour took to the work and the Estate
Managers soon became enthusiastic.

On receipt of this information I made inquiries from Dr. H. H. Mann, a
former Chief Scientific Officer of the Indian Tea Association, as to
whether the live wires among the London Directorate of the tea industry
included anybody likely to be particularly interested in the humus
question.

I was advised to see Mr. James Insch, one of the Managing Directors of
Messrs. Walter Duncan & Co. At Mr. Insch's request an illustrated paper
of instructions for the use of the Managers of the Duncan Group was drawn
up in October 1934 and 250 copies were printed. The Directors of other
groups of tea estates soon began to consider the Indore Process and 4,000
further copies of the paper of instructions were distributed. By the end
of 1934 fifty-three estates of the Duncan Group in Sylhet, Cachar, the
Assam Valley, the Dooars, Terai, and the Darjeeling District had made and
distributed sample lots of humus, about 2,000 tons in all. At the time of
writing, December 1939, the estates of the Duncan Group alone expect to
make over 150,000 tons of humus a year. Similar developments have
occurred in a number of other groups notably on the estates controlled by
Messrs. James Finlay & Co., who have never lost the lead in manufacturing
humus which naturally followed from the pioneering work done by Dr.
Harler in Travancore. A good beginning has been made. The two strongest
groups of tea estates in the East have become compost-minded.

It is exceedingly difficult to say exactly how much humus is being made
at the present time on the tea estates of the British Empire. It is
possible only to give a very approximate figure. In April 1938 Messrs.
Masefield and Insch stated: 'It is probably no exaggeration to say that
to-day a million tons of compost are being made annually on the tea
estates of India and Ceylon, and this has been accomplished within a
period of 5 years.' Since this was written the tea estates of Nyasaland
and Kenya have also taken up the Indore Process with marked success.

These developments have been accompanied by a considerable amount of
discussion. Two views have been and are still being held on the best way
of manuring tea. One school of thought, which includes the tea research
institutes, considers that as the yield of leaf is directly influenced by
the supply of combined nitrogen in the soil, the problem of soil
fertility is so simple as to reduce itself to the use of the cheapest
form of artificial manure--in this case sulphate of ammonia. This view is
naturally vigorously supported by the artificial manure interests. The
results obtained with sulphate of ammonia on small plots at Tocklai and
Borbhetta are triumphantly brought forward to clinch the argument which
amounts to this: that tea can be grown on a conveyor-belt lubricated by
chemical fertilizers. The weaknesses of such an argument are obvious.
These small plots do not represent anything in the tea industry: they
only represent themselves. It is impossible to run a small plot or to
manufacture and sell its produce as a teagarden is conducted. In other
words the small plot is not practical politics. Again, land like Tocklai
and Borbhetta which responds so markedly to sulphate of ammonia must be
badly farmed, otherwise artificials would not prove so potent. The
tendency all the world over is that as the soil becomes more fertile
artificials produce less and less result until the effect passes off
altogether. Bad farming and an experimental technique which will not hold
water are poor foundations on which to found a policy. The use of
replicated and randomized plots, followed by the higher mathematics in
interpreting the results of these small patches of land, can do nothing
to repair the fundamental unsoundness of the Tocklai procedure. It stands
self-condemned. Further, the advocates of sulphate of ammonia for the tea
plant seem to have forgotten that a part at least of the extra yield
obtained with this manure may be due to an increase in soil acidity. Tea,
as is well known, needs an acid soil: sulphate of ammonia increases
acidity.

The humus school of thought takes the view that what matters in tea is
quality and a reserve of soil fertility such as that created by the
primeval forest: that this can only be obtained by freshly prepared humus
made from vegetable and animal wastes and by the correct use of shade
trees, green-manure crops, and the prevention of soil erosion. The moment
the tea soils can be made really fertile, the supply of nitrogen to the
plant will take care of itself and there will be no need to waste money
in securing the fleeting benefits conferred by artificials. The problem
therefore of the manuring of tea is not so much the effect of some
dressing on the year's yield but the building up of a store of fertility.
In this way the manurial problem and the stability of the enterprise as a
going concern become merged into one. It is impossible to separate the
profit and loss account and the balance-sheet of a composting programme
because the annual dressings of humus influence both.

It will be interesting to watch the results of this struggle in a great
plantation industry. At the moment a few of the strongest and most
successful groups are taking up humus and spend little or nothing on
artificials. Other companies, on the other hand, are equally convinced
that their salvation lies in the use of cheap chemical fertilizers.
Between these two extremes a middle course is being followed--humus
supplemented by artificials. Mother earth, rather than the advocates of
these various views, will in due course deliver her verdict.

Can the tea plant itself throw any light on this controversy or is it
condemned to play a merely passive role in such a contest? Has the tea
bush anything to say about its own preference? If it has, its
representations must at the very least be carefully considered. The plant
or the animal will answer most queries about its needs if the question is
properly posed and if its response is carefully studied.

During the early trials of the Indore Process it became apparent that the
tea plant had something very interesting to communicate on the humus
question. Example after example came to my notice where such small
applications of compost as five tons to the acre were at once followed by
a marked improvement in growth, in general vigour and in resistance to
disease. Although very gratifying, in one sense these results were
somewhat disconcerting. If humus acts only indirectly by increasing the
fertility of the soil, time will be needed for the various physical,
biological, and chemical changes to take place. If the plant responds at
once, some other factor besides an improvement in fertility must be at
work. What could this factor be?

In a circular letter issued on October 7th, 1937, to correspondents in
the tea industry, I suggested that the most obvious explanation of any
sudden improvement in tea, observed after one application of compost, is
the effect of humus in stimulating the mycorrhizal relationship which is
known to occur in the roots of this crop.

In the course of a recent tour (November 1937 to February 1938) to tea
estates in the East, I examined the root system of a number of tea plants
which had been manured with properly made compost, and found everywhere
the same thing--numerous tufts of healthy-looking roots associated with
rapidly developing foliage and twigs much above the average. Both below
and above ground humus was clearly leading to a marked condition of
well-being. When the characteristic tufts of young roots were examined
microscopically, the cortical cells were seen to be literally overrun
with mycelium and to a much greater extent than is the rule in a really
serious infection by a parasitic fungus. Clearly the mycorrhizal
relationship was involved. These necessarily hasty and imperfect
observations, made in the field, were. soon confirmed and extended by Dr.
M. G Rayner and Dr. Ida Levisohn, who examined a large number of my
samples including a few in which artificials only were used, or where the
soils were completely exhausted and the garden had become derelict with
perhaps only half the full complement of plants. In these cases the
characteristic tufts of healthy roots were not observed; root development
and growth were both defective; the mycorrhizal relationship was either
absent or poorly developed. Where artificials were used on worn-out tea,
infection by brownish hyphae of a Rhizoctonia-like fungus (often
associated with mild parasitism) was noticed. Whenever the roots of tea,
manured with properly made compost, were critically examined, the whole
of the cortical tissues of the young roots always showed abundant
endotrophic mycorrhizal infection, the mainly intracellular mycelium
apparently belonging to one fungus. The fungus was always confined to the
young roots and no extension of the infection to old roots was observed.
In the invaded cells the mycelium exhibits a regular cycle of changes
from invasion to the clumping of the hyphae around the cell nuclei,
digestion and disintegration of their granular contents, and the final
disappearance of the products from the cells.

Humus in the soil therefore affects the tea plant direct by means of a
middleman--the mycorrhizal relationship. Nature has provided an
interesting piece of living machinery for joining up a fertile soil with
the plant. Obviously we must pay the closest attention to the
response--as regards yield, quality, and disease resistance--which
follows the use of this wonderful bit of mechanism. We must also see that
the humus content of the soil is such that the plant can make the fullest
possible use of its own machinery.

The mycorrhizal relationship in tea and its obvious bearing on the
nutrition of the plant places the manurial problems of this crop on a new
plane--that of applied biology. The well-being of the tea plant does not
depend on the cheapest form of nitrogen but on humus and the consequences
of the mycorrhizal relationship. We are obviously dealing with a forest
plant which thrives best on living humus--not on the dead by-product of a
factory.

It is easy to test the correctness of this view. It can be done in two
ways: (1) by a comparison of tea seedlings grown on sub-soil (from which
the surface soil containing humus has been removed) and manured either
with a complete artificial mixture or with freshly prepared humus, and
(2) by observing the effect of artificials on a tea-garden where the soil
is really fertile. Such trials have already been started. In the case of
seedlings grown on subsoil manured with: (1) no tons of humus to the
acre, or (2) the equivalent amount of NPK in the form of artificials, Mr.
Kenneth Morford has obtained some very interesting results at Mount
Vernon in Ceylon. Nine months after sowing, the humus plot was by far the
better--the plants were 10 high, branched, with abundant, healthy, dark
green foliage. The plots with artificials were 6 inches high, unbranched,
with sparse, unhealthy, pale foliage. An examination of the root systems
was illuminating. The humus plants developed a strong tap root 12 inches
long; the artificials plot showed little attempt to develop any tap root
at all, only extensive feeding roots near the surface. The root system at
once explained why the humus plot resisted drought and why the artificial
manure plot was so dependent on watering. Mr. Morford's experiment should
be repeated in some of the other tea areas of the East. The results will
speak for themselves and will need no argument.

The effect of sulphate of ammonia on a really fertile soil is most
interesting. As would be expected the results have been for the most part
almost negative, because there is no limiting factor in the shape of a
deficiency of nitrogen, phosphorus, or potash under such conditions. On
old estates, where organic matter has not been regularly replaced,
resulting in the loss of much of the original fertility, such an
experiment would give a clear indication as to whether, under existing
management, the soil is losing, maintaining, or gaining in fertility.
Given an adequate supply of humus in the soil, the mycorrhizal
relationship and the nitrification of organic matter, when allowed to
work at top speed, are all that the plant needs to produce a full crop of
the highest quality possible under local conditions. The tea plant
therefore is already preparing its own evidence in the suit--Humus versus
Sulphate of Ammonia.

The problem of the manuring of tea is straightforward. It consists in
converting the mixed vegetable wastes of a tea estate and of the
surrounding land into humus by means of the urine and dung of an adequate
herd of live stock--cattle, pigs, or goats. As the tea districts are
situated in regions of high rainfall it will be necessary in many cases
to protect the heaps or pits from heavy rain. Ample vegetable waste must
also be provided. The solution of the practical problems involved will
necessarily depend on local conditions. At Gandrapara in the Dooars, an
estate influenced by the south-west monsoon, Mr. J. C. Watson has set
about the provision of an ample supply of humus in a very thorough-going
manner, an account of which will be found in Appendix A. It cannot fail
to interest not only the producers of tea but the whole of the plantation
industries as well.

The conversion of vegetable and animal wastes into humus is only one
aspect of the soil-fertility problem of a tea-garden. There are a number
of others such as the use of shade trees, drainage, prevention of
erosion, the best manner of utilizing tea prunings and green-manure, the
utilization of water-weeds like the water hyacinth, the treatment of root
disease, the raising of seed, the manufacture of humus from vegetable
wastes only, and the effect of artificial manures on the quality of tea.
These will now be briefly discussed.

Generally speaking, more attention is paid to shade trees in North-East
India than in South India and Ceylon. There is a tendency for shade to
decrease as one proceeds south. It may be that the factor which has
determined the invariable use of shade in North-East India is the
intense dryness and heat of the period March to June which does not occur
in the south. As, however, tea is a forest plant and tea-growing must
always be looked upon as applied forestry, it would seem to be a mistake
to reduce shade too much. The organic matter provided by the roots and
leaves of the shade trees, the protection they afford the soil from the
sun, wind, and rain, and the well-known advantage of mixed cropping must
all be very important factors in the maintenance of fertility. This is
borne out by the superior appearance of the tea on well-shaded estates in
Ceylon compared with that on land alongside where the shade trees have
been removed.

A large amount of the vegetable wastes on a tea estate consists of
prunings and green-manure plants. These are either forked in, buried in
long shallow trenches, or made into humus. Is there any more effective
method of dealing with these wastes? When the tea is pruned the plant
makes a new bush. Could it not be induced to re-make a portion of its
root system at the same time in well-aerated rich soil? I think it could.
On estates provided with adequate shade and contour drains, the following
two methods of composting tea prunings and green-manure might be tried
out:

1. This material should be forked in with a dressing of compost at the
rate of 5 to 10 tons an acre. Decay will then be much more rapid and
effective than is now the case. This method of the sheet composting of
tea prunings has been tried out and found successful at Gandrapara.

2. The prunings and green-manure should be composted in small pits
between alternate rows of tea. The pits should be 2 feet long and 1-1/2
feet wide and 9 inches to a foot deep, parallel to the drains or contour
drains and so arranged that the roots of every tea plant come in contact
with one pit only. The pits are then nearly half filled with mixed tea
and green-manure prunings, which are then covered with a thin layer of
compost or cattle manure. More green material is added until the pit is
nearly full. It is then covered with three inches of soil. The pits now
become small composting chambers; humus is produced while the tea is not
growing a crop; earthworms are encouraged; the roots of the neighbouring
tea plants soon invade the pit; a portion of the root system of all the
tea plants of the area is then re-created in highly fertile, permeable
soil. When the pruned bushes need tipping on estates where the first
picking is not manufactured, another set of similar pits can be made in
the vacant spaces between the first pits in each line and similarly
filled.

When next the bushes are pruned exactly the same procedure can be carried
out in the hitherto undisturbed spaces between the rows of tea.

When the fourth set of pits has been made each tea bush will have
completed the re-creation of a large portion of its root system in rich
earth.

The first large-scale trial of the pit method was begun at Mount Vernon
in Ceylon in January 1938. The results have been satisfactory in all
respects. the yield of tea has increased: the plants have resisted
drought: the cost of the work has proved to be a sound investment.

On several tea estates in Assam the low-lying areas among the tea are
used for the growth of water hyacinth for the compost heaps. When this
material forms a quarter to a third of the volume of the heap, watering
during the dry season can be reduced very considerably. About
three-quarters of the weed is harvested, the remainder being left to
produce the next year's crop. As water hyacinth is known to diminish the
number of mosquitoes it might pay a tea estate from the point of view of
malaria control only to grow this plant for composting on all low-lying
areas. When water hyacinth becomes widely cultivated on the tea estates
for humus manufacture, the labour employed will undoubtedly carry the
news to the great rice areas of Northeast India. Here one of the greatest
advances in food production in the world can be achieved by the
conversion of water hyacinth first into humus and then into rice.

In many of the tracts which produce tea small areas occur in which the
bushes are attacked by root disease. It is probable that local soil pans,
some distance below the surface, are holding up the drainage and that
this stagnant water lowers the natural resistance of the tea plant. I
suggested in the Report on my tour that vertical pillar drains, filled
with stones, pebbles, or even surface soil, might prevent these troubles.
Similar drains are used in Sweden with good results.

The weakest link in the tea industry is the production of seed. During
the whole of my tour I saw few really well-managed seed gardens. It is
essential that the trees which bear seed should be properly selected,
adequately spaced, well drained, and manured with freshly prepared
compost. Nature will provide an automatic method of seed control. If
diseases appear on the trees or in the seeds something is wrong. Only if
the trees and seed are healthy, vigorous, and free from pests, is the
produce of such trees fit for raising plants, which in China are said to
last a hundred years. The tea plant must have a good start in life.

In Ceylon particularly, attempts have been made to prepare humus without
animal wastes. The results have not furfilled expectation. The breaking
down of such resistant material as the leaves and prunings of tea is then
unsatisfactory: the organisms which synthesize humus are not properly
fed: the residues of these organisms which form an important part of the
final humus lack the contributions of the animal. No one has yet
succeeded in establishing an efficient and permanent system of
agriculture without live stock. There is no reason therefore to suppose
that the tea industry will prove an exception to what, after all, is a
rule in Nature.

One of the most discussed topics in tea is the effect of artificial
manures on quality. The view is widely held that there has been a gradual
loss in quality since chemical manures were introduced. One of the
planters in the Darjeeling District, Mr. G. W. O'Brien, the proprietor of
the Goomtee and Jungpana Tea Estates, who continues to produce tea of the
highest quality, informed me in 1935 that he had never used artificials
since the estates came under his management thirty-one years ago. The
only manure used is cattle manure and vegetable wastes--in other words,
humus. The role of the mycorrhizal relationship in tea helps to provide a
scientific explanation of these results. There can be little doubt that
this relationship will be found to influence the quality of tea as well
as the productivity and health of the bush. Humus and the mycorrhizal
relationship cannot of course create quality where it never existed: the
utmost these factors can achieve is to restore that degree of quality
which any locality possessed when first it was brought from forest under
tea.


SUGAR-CANE

The waste products of the sugar-cane vary considerably. In peasant
agriculture where the whole of the megass is burnt for evaporating the
juice in open pans, the chief waste is old cane leaves, cane stumps, and
the ashes left by the fuel. On the sugar estates, a number of factory
wastes must be added to the above list--filter press cake, some unburnt
megass, and the distillery effluent left after the manufacture of alcohol
(known in Natal as dunder). The main waste in both cases, however, is the
old dead leaves (cane trash), a very difficult material to turn into
humus on account of its structure and its chemical composition.

Before the advent of artificial fertilizers, it was the custom on sugar
estates to maintain animals---mules and oxen--for transport and for
cultivation. These animals were bedded down with cane trash, and a rough
farm-yard manure--known in the West Indies as pen manure--was obtained
with the help of their wastes. Soon after the introduction of artificial
manures, the value of this product began to be assessed on the basis of
chemical analysis. Comparisons were made between the cost of production
of its content of NPK and that of an equivalent amount of these chemical
elements in the form of artificial manure. The result was chemicals soon
began to displace pen manure: the animal came to be regarded as an
expensive luxury. The advent of the tractor and the motor-lorry settled
the question. Why keep expensive animals like mules and oxen which have
to be fed from the land when their work can be done more cheaply by
machines and imported fuel? The decision to give up animals and farm-yard
manure altogether naturally followed because the clearest possible
evidence--that of the profit and loss account--was available. Such false
reasoning is, alas, only too common in agriculture.

The reaction of the sugar-cane crop itself to this change in manuring was
interesting. Two things happened: (1) insect and fungous diseases
increased; (2) the varieties of cane showed a marked tendency to run out.
These difficulties were met by a constant stream of new seedling
varieties. In contrast to this behaviour of the cane on the large estates
is that of the same crop grown by the cultivators of northern India where
the only manure used is cattle manure and where there is practically no
disease and no running out of varieties. The indigenous canes of the
United Provinces have been grown for twenty centuries without any help
from mycologists, entomologists, or plant breeders.

Why does a variety of cane run out and why does it fall a prey to
disease? Sugar-cane is propagated vegetatively from cuttings. When the
buds from which the new canes arise are grown with natural manure in
India, the variety to all intents and purposes is permanent. On the sugar
estates, however, when the buds are raised with chemicals the variety is
short-lived. There must be some simple explanation of this difference in
behaviour.

What happened in the early days of the sugar estates before the advent of
chemicals and before new seedling canes were discovered? In the West
Indies, for example, until the last decade of the last century the
Bourbon variety was practically the only kind grown. There was little or
no disease and this old variety showed no tendency to run out. The
experience of the cultivators of the United Provinces of India has
therefore been repeated on the estates themselves.

The simplest explanation of the breakdown of cane varieties is that
artificials do not really suit the cane and that they lead to incipient
malnutrition. If this is so the synthesis of carbohydrates and proteins
will be slightly imperfect: each generation of the cane will start
somewhat below par. The process will eventually end in a cane with a
distinct loss in vegetative vigour and unable to resist the onslaughts of
the parasite. In other words, the variety will have run out.

This hypothesis will be transformed into something approaching a
principle if it can be proved that the cane is a mycorrhiza-former and is
nourished in two ways: (1) by the carbohydrates and proteins synthesized
in the green leaves, and (2) the direct digestion of fungous mycelium in
the roots.

Steps were taken during 1938 and 1939 to have the roots of sugar-cane
examined in order to test this point of view. Material was obtained from
India, Louisiana, and Natal. In all cases the roots exhibited the
mycorrhizal association. The large amount of material sent from Natal
included canes grown with artificials only, with humus only, and with
both. The results were illuminating. Humus is followed by the
establishment of abundant mycorrhiza and the rapid digestion of the
fungus by the roots of the cane. Artificials tend either to eliminate the
association altogether or to prevent the digestion of the fungus by the
roots of the cane. These results suggest that the change over from pen
manure to artificials is at the root of the diseases of the cane and is
the cause of the running out of the variety. We are dealing with the
consequences of incipient malnutrition--a condition now becoming very
general all over the world in many other crops besides sugarcane.

These observations leave little doubt that the future policy in
cane-growing must be the conversion of cane trash and other wastes into
humus. The difficulty in composting cane trash, however, is to start the
fermentation and then to maintain it. The leaves are armour-plated and do
not easily absorb water. Further, the material is low in nitrogen (about
0.25 per cent.) while the ash (7.3 per cent. of the mass) contains 62 per
cent. of silica. The micro-organisms which manufacture humus find it
difficult to start on such refractory material. The problem is how best
to help them in their work: (1) by getting the trash to absorb water, and
(2) by providing them with as much easily fermentable vegetable matter as
possible. Molasses where available can be used to help the fermentation.
If humus of the highest quality is to be synthesized an adequate supply
of urine and dung must also be provided, otherwise a product without the
accessory growth substances will result. Given a reasonable supply of
urine and dung and sufficient easily fermentable vegetable wastes like
green-manure, there is no reason why cane trash and the other wastes of a
sugar plantation cannot be made into first-class humus and why a sugar
estate should not be made to manure itself. The conditions which must be
fulfilled are clear from the work already done. Dymond has shown that
before composting, cane trash must be allowed to weather a little: the
weathered leaves must then be kept moist from the start. In this way the
fungi and bacteria are greatly assisted. Filter press cake, dander, and
other wastes all help in the process of conversion, as will be seen from
the results of his various experiments carried out in 1938 in Natal
(Table 2).


TABLE 2

Composting cane trash in Natal

Composted      Moisture   Loss on    N   Total   Available   Total  Avail.
   with                   ignition       P205      P205       K20      K20

1. Kraal manure  60.5      30.6    0.74  0.28      0.14       S.T.      --
2. Filter cake   74.2      44.0    0.67  0.68      0.52       S.T.      --
3. Kraal manure
and filter cake  61.0      33.3    0.71  0.40      0.28       S.T.      --
4. Kraal manure,
filter cake
and  molassas    64.8      34.6    0.70  0.40      0.20        T.     S.T.
5. Dunder        28.5      20.0    0.72  0.40      0.21       0.52    0.30
6. Kraal manure,
filter cake,
ammonium sulphate,
and potassium
sulphate         59.2      27.8   1.00  0.42       0.29       0.72    0.49
7. Farm composts
with available
materials        55.5      27.6   0.78  0.32       0.24       S.T.      --
8. Farm composts
with available
materials        52.2      29.6   0.67  0.89       0.56       S.T.      --
9. Farm composts
with available
materials        57.8      33.1   0.91  0.56       0.44       S.T.      --
10. Farm composts
with available
materials        41.0      30.0   0.84  0.44       0.36       S.T.      --
11. Farm composts
with available
materials        29.2       9.9   0.67  0.27       0.20       S.T.      --


These results are similar to and confirm those obtained by Tambe and Wad
at Indore in 1935. In Natal it is estimated that 100 tons of stripped
cane will yield about 40 tons of compost containing about 280 lb. of
nitrogen and 160 lb. of phosphoric acid.

The main difficulty in composting cane trash must always be the
correction of its wide carbon: nitrogen ratio. The problem is a practical
one--how best to bring the various wastes together in the cheapest way
and then distribute the finished humus to the land. Obviously there can
be no hard-and-fast procedure. The correct solution of the problem will
vary with the locality: the work is such that it can only be done by the
man on the spot.

The sugar estates of the future will in all probability gradually become
self-supporting as regards manure. After a time no money will be spent on
artificials. The change over from present methods of manuring will,
however, take time, and at first a sufficient volume of high-quality
humus will be out of the question because the animals maintained will be
too few.

What is the best way of using the small amount of humus that can be made
at the beginning? This is a very important matter. I suggest that it
should be devoted to the land on which the plant material is grown. These
canes should be raised in trenches on the Shahjahanpur principle (see
Chapter XIV) and every care should be taken to maintain the aeration of
the soil during the whole life of the crop. The trenches should be well
cultivated and manured with freshly prepared humus, at least three months
before planting. These canes should be regarded as the most important on
the estate, and no pains should be spared to produce the best possible
material. Whether or not immature cane should continue to be planted is a
question for the future. What is certain is that cane to be planted
should be really well grown in a soil rich in freshly prepared humus.
Each crop must start properly. As the supply of organic matter increases
on the sugar estates the methods found to give the best results in
growing these canes can be extended to the whole estate.

That the above is possible is clear from a study of the work that has
been done in India and Natal. In March 1938 Dymond concluded a careful
survey of the whole problem in the following words:


'Artificials are easy of application, easily purchased in good times, or
not bought at all when times are bad; they form a never-ending topic of
conversation with one's neighbours, a source of argument with the
vendors; they are a duty and a sop to one's conscience; whereas humus
means more labour, more attention, transport and trouble. Nevertheless,
humus is the basis of permanent agriculture, artificials the policy of
the here to-day and gone to-morrow.'


COTTON

Before taking up research on cotton at the newly founded Institute of
Plant Industry at Indore in 1924, a survey of cotton growing in the
various parts of India was undertaken. At the same time the research work
in progress on this crop was critically examined.

The two most important cotton-growing areas in India are: (1) the black
cotton soils of the Peninsula, which are derived from the basalt; (2) the
alluvium of North-West India, the deposits left by the rivers of the
Indo-Gangetic plain.

In the former there are thousands of examples which indicate beyond all
doubt the direction research on this crop should take. All round the
villages on the black cotton soils, zones of highly manured land rich in
organic matter occur. Here cotton does well no matter the season: the
plants are well grown and free from pests: the yield of seed cotton is
high. On the similar but unmanured land alongside the growth is
comparatively poor: only in years of well distributed rainfall is the
yield satisfactory. The limiting factor in growth is the development,
soon after the rains set in, of a colloidal condition which interferes
with aeration and impedes percolation. This occurs on all black soils,
but organic matter mitigates the condition.

On the alluvium of North-West India, a similar limiting factor occurs.
Here cotton is grown on irrigation, which first causes the fine soil
particles to pack and later on to form colloids. In due course the
American varieties in particular show by their growth that they are not
quite at home. The anthers often fail to function properly, the plants
are unable to set a full crop of seed, the ripening period is unduly
prolonged, and the fibre lacks strength, quality, and life. The cause of
this trouble is again poor soil aeration, which appears in these soils to
lead to a very mild alkali condition. This, in turn, prevents the cotton
crop from absorbing sufficient water from the soil. One of the easiest
methods of preventing this packing is by assisting the soil to form
compound particles with the help of dressings of humus.

The basis of research work on cotton in India was therefore disclosed by
a study in the field of the crop itself. The problem was how best to
maintain soil aeration and percolation. This could be solved if more
humus could be obtained. Good farming methods therefore provided the key
to the cotton problems of India.

A study of the research work which has been done all over the world did
nothing to modify this opinion. The fundamental weakness in cotton
investigations appeared to be the fragmentation of the factors, a loss of
direction, failure to define the problems to be investigated, and a
scientific approach on far too narrow a front without that balance and
stability provided by adequate farming experience.

Steps were therefore taken to accelerate the work on the manufacture of
humus which had been begun at the Pusa Research Institute. The Indore
Process was the result. It was first necessary to try it out on the
cotton crop. The results are summed up in the following Table:


TABLE 3

The increase general fertility at Indore

Year  Area in acres of  Average yield  Yield of the best plot  Rainfall
       improved land      in lb. per     of the year in        in inches
        under cotton       acre           lb. per acre

1927      20.60             340              384              27.79
                                                        (distrib. good)
1928       6.64             510              515              40.98
                                                  (a yr of excessive rain)
1929      36.98             578              752              23.11
                                                       (distribution poor)


The figures show that, no matter what the amount and distribution of
rainfall were, the application of humus soon trebled the average yield of
seed cotton--200 lb. per acre--obtained by the cultivators on similar
land in the neighbourhood.

In preparing humus at Indore one of the chief wastes was the old stalks
of cotton. Before these could be composted they had to be broken up. This
was accomplished by laying them on the estate roads, where they were soon
reduced by the traffic to a suitable condition for use as bedding for the
work-cattle prior to fermentation in the compost pits.

The first cotton grower to apply the Indore Process was Colonel (now Sir
Edward) Hearle Cole, C.B., C.M.G., at the Coleyana Estate in the
Montgomery District of the Punjab, where a compost factory on the lines
of the one at the Institute of Plant Industry at Indore was established
in dune 1932. At this centre all available wastes have been regularly
composted since the beginning: the output is now many thousands of tons
of finished humus a year. The cotton crop has distinctly benefited by the
regular dressings of humus; the quality of the fibre has improved; higher
prices are being obtained; the irrigation water required is now one-third
less than it used to be. The neighbouring estates have all adopted
composting: many interested visitors have seen the work in progress. One
advantage to the Punjab of this work has, however, escaped attention,
namely, the importance of the large quantities of well-grown seed, raised
on fertile soil, contributed by this estate to the seed distribution
schemes of the Provincial Agricultural Department. Plant breeding to be
successful involves two things--an improved variety plus seed for
distribution grown on soil rich in humus.

The first member of an Agricultural Department to adopt the Indore Method
of composting for cotton was Mr. W. J. Jenkins, C.I.E., when Chief
Agricultural Officer in Sind, who proved that humus is of the greatest
value in keeping the alkali condition in check, in maintaining the health
of the cotton plant, and in increasing the yield of fibre. At Sakrand,
for example, no less than 1,250 cartloads of finished humus were prepared
in 1934-5 from waste material such as cotton stalks and crop residues.

During recent years the Indore Process has been tried out on some of the
cotton farms in Africa belonging to the Empire Cotton Growing
Corporation. In Rhodesia, for example, interesting results have been
obtained by Mr. J. E. Peat at Gatooma. These were published in the
Rhodesia Herald of August 17th, 1939. Compost markedly improved the fibre
and increased the yield not only of cotton but also of the rotational
crop of maize.

Why cotton reacts so markedly to humus has only just been discovered. The
story is an interesting one, which must be placed on record. In July 1938
I published a paper in the Empire Cotton Growing Review (vol. xv, no. 3,
1938, p. 186) in which the role of the mycorrhizal relationship in the
transmission of disease resistance from a fertile soil to the plant was
discussed. In the last paragraph of this paper the suggestion was made
that mycorrhiza 'is almost certain to prove of importance to cotton and
the great differences observed in Cambodia cotton in India, in yield as
well as in the length of the fibre, when grown on (1) garden land (rich
in humus) and (2) ordinary unmanured land, might well be explained by
this factor'. In the following number of this Journal (vol. xv, no. 4,
1938, p. 310) I put forward evidence which proved that cotton is a
mycorrhiza-former. The significance of this factor to the cotton industry
was emphasized in the following words:


'As regards cotton production, experience in other crops, whose roots
show the mycorrhizal relationship, points very clearly to what will be
necessary. More attention will have to be paid to the well tried methods
of good farming and to the restoration of soil fertility by means of
humus prepared from vegetable and animal wastes. An equilibrium between
the soil, the plant and the animal can then be established and
maintained. On any particular area under cotton, a fairly definite ratio
between the number of live stock and the acreage of cotton will be
essential. Once this is secured there will be a marked improvement in the
yield, in the quality of the fibre and in the general health of the crop
All this is necessary if the mycorrhizal relationship is to act and if
Nature's channels of sustenance between the soil and the plant are to
function. Any attempt to side-track this mechanism is certain to fail.

'The research work on cotton of to-morrow will have to start from a new
base line--soil fertility. In the transition between the research of
to-day and that of the future, a number of problems now under
investigation will either disappear altogether or take on an entirely new
complexion. A fertile soil will enable the plant to carry out the
synthesis of proteins and carbohydrates in the green leaf to perfection.
In consequence the toll now taken by fungous, insect and other diseases
will at first shrink in volume and then be reduced to its normal
insignificance. We shall also hear less about soil erosion in places like
Nyasaland where cotton is grown, because a fertile soil will be able to
drink in the rainfall and so prevent this trouble at the source.'


Confirmation of these pioneering results soon followed. In the
Transactions of the British Mycological Society (vol. xxii, 1939, p. 274)
Butler mentions the occurrence of mycorrhiza as luxuriantly developed in
cotton from the Sudan and also in cotton from the black soils of Gujerat
(India). In the issue of Nature of July 1st, 1939, Younis Sabet recorded
the mycorrhizal relationship in Egypt. In the Empire Cotton Growing
Review of July 1939 Dr. Rayner confirmed the existence of mycorrhiza in
both Cambodia and Malvi cotton grown at my suggestion by Mr. Y. D. Wad at
Indore, Central India, in both black cotton soil and in sandy soil from
Rajputana.


SISAL

As is well known, the leaves of the sisal plant yield about 93 per cent.
of waste material and about 7 per cent. of fibre, of which not more than
5 per cent. is ordinarily extracted. The wastes are removed from the
decorticators by a stream of water, usually to some neighbouring ravine
or hollow in which they accumulate. Sometimes they are led into streams
or rivers. The results are deplorable. Putrefaction takes place in the
dumps and nuisance results, which can be detected for miles. The streams
are contaminated and the fish are killed. On account of these primitive
methods of waste disposal, the average sisal factory is a most depressing
and disagreeable spot. Further, the water used in these operations--which
has to be obtained at great expense by sinking wells or boreholes, by
making dams or reservoirs, and then raised by pumping plants--is allowed
to run to waste. Two of the pressing problems, therefore, of the sisal
industry are: (1) the conversion of the solid residues, including the
short fibres, into some useful product like humus, and (2) the use of the
waste water for raising irrigated crops.

These two problems have been successfully solved on Major Grogan's estate
at Taveta in Kenya, by the Manager, Major S. C. Layzell, M.C. The work
began in 1935 and has been steadily developed since. An account of the
results was published in the East African Agricultural Journal of July
1937.

The first problem was to separate the liquid in the flume waste from the
solids. At Taveta all the waste from the decorticator is passed over a
grid at the end of the flume. The grid retains the solids and allows the
acid 'soup' to pass into a concrete sump below, from which it is carried
by a suitably graded channel, with a fall of 1 in 1,000, to the irrigated
area. From the grid the solid waste is moved on slatted trucks (the usual
four-wheel frame constructed of timber with a platform of slats arranged
at right angles to the track) to a concrete basin where they are allowed
to drain The drainage water from this basin is led by a small irrigation
furrow to another area where it is utilized for growing crops. There are
thus two sources of irrigation water--the main flume water and the
drainage from the loaded trucks


(Plate I).
(not in etext)
CONVERSION OF SISAL WASTE.
Above: Filtering the waste.
Middle: Draining.
Below: Irrigation with waste-water.


The lay out of the composting ground is important. Sisal poles, in groups
of four, equally spaced, are arranged on both sides and at right angles
to the rail track. On these poles, placed a foot apart for providing
aeration from below, the waste is lightly spread to a height of 2 feet
in heaps measuring 15 feet by 4 feet. As all new heaps require a starter,
any estate making compost for the first time should obtain a small supply
of freshly made humus from some other sisal estate which has adopted the
Indore Process. A few handfuls of this old compost, distributed evenly
in the heaps, is sufficient to start fermentation. The waste is left
on the poles for thirty days during which the breaking-down process,
by means of thermophyllic bacteria, begins. The temperature rises to
a point where it is impossible to bear one's hand in the heap.

The first turn takes place thirty days after the first formation of the
heap when the contents of two heaps are run together into one, as by this
time the volume has considerably decreased. After the first turn the
decomposition is carried a stage further, mainly by fungi. During this
phase the whole heap is often covered each morning with a long-stemmed
toadstool (Plate II).


PLATE II.
(not in etext)
CONVERSION OF SISAL WASTE.
Above: Light railway and foundation of sisal poles.
Middle: Spreading.
Below: Turned heaps with layers of elephant grass.


At the end of another thirty days the second turn takes place. The
ripening process then begins and is completed about the ninetieth day
after the original heaps were made. Major Layzell writes that the final
product resembles first-class leaf mould and contains 1.44 per cent. of
nitrogen. On the basis of its chemical composition alone the compost has
been valued locally at 2 pounds a ton.

A large portion of the humus is devoted to the sisal nurseries in order
that all new areas can be started with vigorous and properly grown
plants. The remainder finds its way to the areas producing sisal.

The sisal plant only does well on fertile soil and therefore needs
intensive rather than extensive cultivation. Whenever this is forgotten
the enterprise ends in bankruptcy for the reason that, as the soil near
the factory is exhausted, the lead to the decorticators soon eats up the
profit. The game is no longer worth the candle. The conversion of the
wastes into humus will therefore solve this problem: the fertility of the
land round the factory can be maintained and even improved. Further, the
dumps of repulsive sisal waste will be a thing of the past.

The labour employed in dealing with the waste and turning the heaps from
a decorticator producing 120 tons of fibre per month is thirty-four with
two head men. Sixteen additional men were taken up on the grid and with
the trucks, so that a labour force of fifty in all with two head men was
needed for making compost at this centre. There is no difficulty in
handling sisal wastes provided the workmen are given a supply of some
cheap oil for protecting the skin, otherwise the juice of the leaves
produces eczema on the arms and legs of those engaged on the work.

The flume liquid is mainly used for growing food crops for the labour
force so as to improve the usual set ration of mealie-meal, beans, and
salt. The psychological effect of all this on the labourers has been
remarkable: the spectacle of a large area of bananas, sugar-cane, citrus
plants, and potatoes removes all fear of a possible lack of food from the
minds of the workers and their families: they feel safe. Further, their
physical health and their efficiency as labourers rapidly improve. A
guaranteed food-supply has proved a great attraction to labour and has
provided a simple and automatic method of recruitment.

At Taveta the soil contains a good deal of lime so that the prior
neutralization of the acid irrigation water is unnecessary. On other
estates this point might have to receive attention. Perhaps the easiest
way to get rid of the acidity would be to add sufficient powdered crude
limestone to the flume water just after the solids have been separated
for composting.

Two conditions must be fulfilled before the methods worked out at Taveta
can be adopted elsewhere: (1) there must be a suitable area of flat land
near the factory for growing irrigated crops; (2) the general layout must
be such that there is ample room for a composting ground to which the
wastes can be taken by a light railway and from which the finished humus
can be easily transported to the irrigated area and to the rest of the
estate.

One obvious improvement in the manufacture of humus on a sisal estate
must be mentioned. Animal residues must be added to the vegetable wastes.
If it is impossible to maintain sufficient live stock for all the sisal
waste, two grades of humus should be made: first grade with animal manure
for the parent plants and the nurseries, second grade for the plants
which yield fibre.


MAIZE

One of the great weaknesses in British agriculture at the moment is the
dependence of our live stock--such as pigs, poultry, and dairy
animals--on imported foodstuffs. Our animal industry is becoming just as
unbalanced as regards the supply of nutriment grown on fertile soil as
our urban population. One of the animal foods imported in large
quantities is maize. Unfortunately a large proportion of this import is
being grown on worn-out soils. We are feeding our animals and indirectly
ourselves on produce grown anywhere and anyhow so long as it is cheap.

Mother earth, however, has registered an effective protest. The maize
soils of such areas as Kenya and Rhodesia soon showed signs of
exhaustion. The yields fell off. Any one who has had any practical
experience of maize growing could have foretold this. This crop requires
a fertile soil.

The maize growers of Kenya, Rhodesia, and South Africa soon learnt this
lesson. The constant cropping of virgin land with an exhausting crop
rapidly reduced the yield. This happened just as the Indore Process was
devised. Its application to the maize fields of Kenya and Rhodesia led to
good results. The composting of the maize stalks and other vegetable
residues, including green-manure crops, was taken up all over Kenya and
Rhodesia.

Two examples out of many of the results which are being obtained may be
quoted: at Rongai in Kenya, Mr. J. E. A. Wolryche Whitmore has adopted
the Indore Process on three farms. The working oxen are being bedded down
during the night with dry maize stalks, wheat-straw, grass, and other
roughage available. After a week under the cattle this is composted in
pits with wood-ashes and earth from under the animals. If insufficient
earth is used a high temperature is not maintained. Two turns at
intervals of a month yield a satisfactory product after ninety days. The
effect on the maize crop is very marked. In Rhodesia, Captain J. M.
Moubray has obtained similar results. (These are described in detail in
Appendix B).

One of the pests of maize in Rhodesia--the flowering parasite known
locally as the witch-weed (Striga lutea)--can be controlled by humus.
This interesting discovery was made by Timson whose results were
published in the Rhodesia Agricultural Journal of October 1938. Humus
made from the soiled bedding in a cattle kraal, applied at the rate of 10
tons to the acre to land severely infested with witch-weed, was followed
by an excellent crop of maize practically free from this parasite. The
control plot alongside was a red carpet of this pest. A second crop of
maize was then grown on the same land. Again it was free from witch-
weed. This parasite promises to prove a valuable censor for indicating
whether or not the maize soils of Rhodesia are fertile. If witch-weed
appears, the land needs humus; if it is absent, the soil contains
sufficient organic matter. Good farming will therefore provide an
automatic method of control.

Humus is bound to affect the quality of maize as well as the yield. In
the interests both of the maize-exporting and the maize-importing
countries, a new system of grading and marketing the produce of fertile
soil should be introduced. Maize grown on land manured with properly made
humus and without the help of artificials should be so described and
graded. Only in this way can well-grown produce come into its own. It
should be clearly distinguished in its journey from the field to the
animal and kept separate from inferior maize. Purchasers will then know
that such graded produce fed to their live stock will have been properly
grown. They will soon discover that it suits their animals. This question
of grading produce according to the way it is grown applies to many other
crops besides maize. Its importance to the future of farming and the
health of the nation is referred to in a later chapter.


RICE

By far the most important food crop in the world is rice. It will be
interesting therefore to see what response this cereal makes to humus. We
should expect it would be considerable, because the rice nurseries are
always heavily manured with animal manure and just before transplanting
the seedlings are much richer in nitrogen than at any further stage in
the life of the plant.

The first trial of the Indore Process was made by the late Mrs. Kerr at
the Leper Home and Hospital, Dichpali in H.E.H. the Nizam's Dominions.
Her reaction after reading The Waste Products of Agriculture in 1931 was:
'If he is right it will mean the utter economic revolution of India's
villages.' Rice was selected as the crop on which to test the method. She
died while the trial was in progress. The results are summed up in a
letter from her husband, the Rev. G. M. Kerr, dated Dichpali, November
2nd, 1933, as follows:


'We have cut three and entirely average portions of our rice fields. No.
1 plot had 1.25 to 1.5 inches of Indore compost ploughed in. No. 2 plot
had some farm rubbish plus 3/8 inch of Indore compost. No. 3 plot was the
control and had nothing.

'Since we are eager to get these figures off to you the tabulated weight
results of the straw cannot be given. Plot No. I was cut It days ago;
plot No. 2 only 2 days ago, and plot No. 3 yesterday. No. 1, therefore,
is dry, and Nos. 2 and 3 are still wet. We have given the straw results
in similar sized bundles, but No. 1 is the better straw and will make
considerably better buffalo fodder (Table 4).

'Once we get all our 30 acres of rice fields fully composted we shall be
able to welcome 50 or 60 more lepers here for cleansing. This is not a
scientific conclusion according to your usual methods of reckoning, but
it is the practical issue as it appeals to us.'


In a subsequent letter dated October both, 1935, the Dichpali experience
of the Indore Process was summed up as follows:


'Indore compost is one of the material blessings of this life, like
steam, electricity and wireless. We simply could not do without it here.
It has transformed all our agricultural interests. We have 43 acres under
wet cultivation, and most of the land three years ago was of the poorest
nature, large patches of it so salty that a white alum-like powder lay on
the surface. We have now recovered 28 acres, and on these we are having a
bumper crop of rice this year. There have never been such crops grown on
the land, at least not for many years. The remaining 15 acres are as
before with the rice scraggy and thin. By means of our factory of 30 pits
we keep up a supply of compost, but we can never make enough to meet our
needs. We are now applying it also on our fields of forage crops with
remarkable results. Compost spread over a field to the depth of about one
quarter of an inch ensures a crop at least three or four times heavier
than otherwise could be obtained.'


TABLE 4

Crop results of three plots of rice grown under varying conditions
at the Home for Lepers, Dichpali

                                 No. 1 Plot      No. 2 Plot     No. 3 Plot

 Amount of land measured for the
 contrast. All portions had the same
 cultivation                   6,394 sq. ft.   6,394 sq. ft. 6,394 sq. ft.

Amount of seed sown. All the seed
sown was the same quality           6 lb.            6 lb.           6 lb.

Amount of rice taken in each case
by measure, not weight            422 lb.          236 lb.          60 lb.

Amount of straw in similar
sized bundles                  138 bundles      106 bundles     40 bundles


The marked response of rice to organic matter in the rice nurseries is
well known. The Dichpali results prove that the transplanted crop also
responds to humus. In the nurseries the soil conditions are aerobic:
after transplanting, the roots of the crops are under water, when the
oxygen supply largely depends on the activities of algae. How does humus
influence the rice plant in water culture under conditions when the
active oxygen must be dissolved in water? Do the roots of rice in the
nurseries and also after transplanting exhibit the mycorrhizal
relationship? If they do, the explanation of the Dichpali results is
simple. If they do not, how then does humus in wet cultivation influence
photosynthesis in the green leaf? Nitrification of the organic matter
would seem difficult under such conditions for two reasons: (1) the
process needs abundant air; (2) the nitrate when formed would undergo
excessive dilution by the large volume of water in the rice fields. If,
however, the mycorrhizal association occurs in transplanted rice, the
Dichpali results explain themselves.

While this book was passing through the press specimens of surface roots
of transplanted rice, 116 days from the date of sowing, grown in soil
manured with humus, were collected on October 27th, 1939, by Mr. Y. D.
Wad in Jhabua State, Central India. They were examined by Dr. Ida
Levisohn on December 11th, 1939, whose report reads as follows:


'The stouter laterals of the first order show widespread endotrophic
mycorrhizal infection, the mycorrhizal regions being indicated
macroscopically by opacity, beading and the absence of root hairs. The
active hyphae are of wide diameter; they pass easily through the cell
walls and form coils, vesicles and arbuscles; they show the early and
later stages of digestion. The resulting mass of granular material
appears to be rapidly translocated from the cells.'


There is no doubt that rice is a mycorrhiza-former, a fact which at once
explains the remarkable response of this crop to humus and which opens up
a number of new lines of investigation. Yield, quality, disease
resistance, as well as the nutritive value of the grain will in all
probability be found to depend on the efficiency of the mycorrhizal
association.


VEGETABLES

One of the chief problems in market gardening in the open and under glass
is the supply of humus. In the past, when horse transport was the rule
and large numbers of these animals were kept in the cities, it was the
custom, near London for example, for the wagons which brought in the
crates of vegetables for the early morning market to take back a load of
manure. The introduction of the internal combustion engine changed this:
a general shortage of manure resulted. In most cases market gardens are
not run in connexion with large mixed farms, so there is no possibility
of making these areas self-supporting as regards manure: the essential
animals do not exist. The result is that an increasing proportion of the
vegetables sold in the cities is raised on artificial manure. In this way
a satisfactory yield is possible, but in taste, quality, and keeping
properties the product is markedly inferior to the vegetables raised on
farm-yard manure.

It is an easy matter to distinguish vegetables raised on NPK. They are
tough, leathery, and fibrous: they also lack taste. In marked contrast
those grown with humus are tender, brittle, and possess abundant flavour.
One of the lessons in dietetics which should be taught to children in
every school and institution in the country, and also in every home,
should be the difference between vegetables, salads, potatoes, and fruit
grown with humus or with artificials. Evidence is accumulating that
liability to common ailments like colds, measles, and so forth becomes
much less when the vegetables, fruit, potatoes, and other food consumed
are raised from fertile soil and eaten fresh.

How is the necessary humus for the high-quality vegetables needed by
urban areas to be obtained? Two solutions of the problem are possible.

In the first place, market gardening should, whenever possible, be
conducted as a branch of mixed farming with an adequate head of live
stock, so that all the waste products, vegetable and animal, of the
entire holding can be converted into humus by the Indore Process. The
first trial of this system was carried out at the Iceni Nurseries,
Surfleet, Lincolnshire. The work commenced in December 1935 and can best
be described in Captain Wilson's own words taken from a memorandum he
drew up for the members of the British Association who visited his farm
on September 4th, 1937:


'The Iceni Estate consists of about 325 acres comprised as follows:--
Arable land, etc. . . . . . . . . . .  225 acres
Permanent grassland . . . . . . . . . 30
Rough wash grazings . . . . . . . . . 35
Land under intensive horticulture . . 35



'The main idea in the development of the estate has been to prove that
even to-day, in certain selected areas of England, it is a commercial
proposition to take over land which has been badly farmed, and bring it
back to a high state of fertility, employing a large number of persons
per acre.

'To this end the estate has been developed as a complete agricultural
unit with a proper proportion of live stock, arable land, grass land
and horticulture, with the belief that after a few years of proper
management the estate can become very nearly, if not entirely, a
self-supporting unit, independent of outside supplies of chemical manures,
etc., and feeding stuffs, the land being kept in a high state of
fertility, which is quite unusual to-day, by:

(1) A proper balance of cropping.

(2) The conversion of all wheat straw into manure in the crew yards and
the utilization of this manure and as much as possible of the waste
products of the land for making humus for the soil.

'As regards (2), the method of humus-making which has been employed is
known as "The Indore Process", and it has proved successful. The output
in 1936 amounted to approximately 700 tons, and in the current year will
probably be about 1,OOO tons.

'As a result of this utilization of humus, the land under intensive
cultivation has already reached a state of independence, and for the last
two years no chemicals have been used in the gardens at all either as
fertilizers or as sprays for disease and pest control. The only wash
which has been used on the fruit trees is one application each winter of
lime sulphur, and it is hoped to eliminate this before long.

'The farm land is not yet independent of the purchase of fertilizers,
but the amount used has been steadily reduced from 106 tons used in 1932,
costing 675 pounds, to 40-1/2 tons in the current year, costing 281
pounds. Similarly the potato crop, which formerly was sprayed four or
five times, is now only sprayed once, and this it is hoped will also be
dispensed with before many years when the land has become healthy and in
a proper state of fertility.

'Eventually, with a properly balanced crop rotation, there is no doubt
in my mind that the same degree of independence can be reached on the
farm as has already been attained on my market-garden land.

'The probable cropping will eventually work out as follows:

75 acres potatoes.
75 acres wheat.
25 acres barley, oats, beans and linseed (for stock feeding).
15 acres roots (for stock feeding).
30 acres one year clover and rye-grass leys for feeding with pigs and
poultry and cutting for hay, ploughing in the aftermath.

'The live stock carried on the farm at the June returns was as follows:
22 cattle (cows and young stock of my own breeding).

14 horses (including foals).
15 sows (for breeding).
103 other pigs.
120 laying hens (of my own stock).

'And although it is rather early to say, I believe that the above
figures may be about right for the size of the farm, with the addition
of about So cattle for winter yard feeding. This latter importation will
be rendered unnecessary in a few years when the number of cattle of my
own breeding will have increased.'


Since this memorandum a further advance has been made at Surfleet. The
factor which at present limits production on the alluvial soils in the
Holland Division of Lincolnshire (in which Captain Wilson's vegetable
garden is situated) is undoubtedly soil aeration. These soils pack
easily, so the supply of oxygen for the micro-organisms in the soil and
for the roots of the crops is frequently interrupted. Sub-soil drainage
tends to reduce this adverse factor. During the autumn of 1937 the whole
of Captain Wilson's vegetable area was pipe drained. As was expected, the
improvement in soil aeration which instantly followed has enabled the
crops to obtain the full benefit of humus. Here is a definite example
where the establishment of Nature's equilibrium between the soil, the
plant, and the animal has resulted in increased crops and in higher
quality produce.

Another and perhaps a simpler solution of the organic matter problem in
vegetable growing is to make use of the millions of tons of humus in the
controlled tips in the neighbourhood of our cities and towns. This
subject is discussed in detail in Chapter VIII.


VINE

A comparison between the cultivation of the vine in the East and the West
is interesting in more than one respect. In the Orient this crop is grown
mostly for food: in the Occident, including Africa, most of the grapes
are made into wine.

The feature of the cultivation of the vine in Asia is the long life of
the variety, the universal use of animal manure, and the comparative
absence of insect and fungous diseases. Artificial manures, spraying
machines, and poison sprays are unknown.

In the West the balance between the area under vines and the number of
live stock has been lost: the vine has largely displaced the animal: the
shortage of farm-yard manure has been made up by the chemical fertilizer:
the life of the variety is short: insect and fungous diseases are
universal: the spraying machine and the poison spray are to be seen
everywhere: the loss of balance in grape growing has been accompanied by
a lowering in the quality of the wine.

During the last three summers, in the course of extensive tours in
Provence, a sharp look-out was kept for vineyards in which the appearance
of the vines tallied in all respects with those of Central Asia, namely,
well-grown plants which looked thoroughly at home, and in which the
foliage and young growth possessed real bloom. At last near the village
of Jouques in the Department of Bouches du Rhone such vines were found.
They had never received any artificials, only animal manure: the vineyard
had a good local reputation for the quality of its wine. Arrangements
were made with the proprietress to have the active roots examined. They
exhibited the mycorrhizal association. The vine is a mycorrhiza--former
and therefore humus in the soil is essential for perfect nutrition; the
long life of the variety and the absence of disease in Central Asia are
at once explained.

In a recent survey of fruit growing in the Western Province of the Union
of South Africa, which appeared in the Farmer's Weekly (Bloemfontein) of
August 23rd, 1939, Nicholson refers to a local vineyard, on the main road
between Somerset West and Stellenbosch, which has taken up the Indore
Process:


'Motorists travelling along this road cannot help noticing how healthy
this farmer's vineyards look and how orderly is the whole farm. Early
this winter I visited it in time to see the huge stacks of
manure--beautiful, finely rotted bush which had been helped to reach that
state by being placed in the kraal under the animals. Pigs had played
their part too. During the wine-pressing season all the skins of the
grapes are fed to the pigs and later returned to the vineyards in the
form of manure.'


When the vine growers of Europe realize how much they are losing by an
unbalanced agriculture in the shape of the running out of the variety,
loss of resistance to disease, and loss of quality in the wine, steps
will no doubt be taken by a few of the pioneers to increase the head of
live stock, to convert all the available wastes into humus, and to get
back to Nature as quickly as possible.



BIBLIOGRAPHY

DYMOND, G. C. 'Humus in Sugar-cane Agriculture', South African Sugar
Technologists, 1938.

HOWARD, A. 'The Manufacture of Humus by the Indore Process,, Journal of
the Royal Society of Arts, lxxxiv, 1935, P. 25 and lxxxv, 1936, p. 144.

------'Die Erzeugung von Humus nach der Indore-Methode',
Der Tropenpflanzer, xxxix, 1936, p. 46.

-------'The Manufacture of Humus by the Indore Process', Journal of
the Ministry of Agriculture, xiv, 1938, p. 431.

'En Busca del Humus', Revista del Istituto de Defensa del Cafe de
Costa Rica, vii, 1939, P. 427.

LAYZELL, S. C. 'The Composting of Sisal Wastes', East African
Agricultural Journal, iii, 1937, P 26

TAMBE, G. C., and WAD, Y. D. 'Humus-manufacture from Cane-trash',
International Sugar Journal, 1935, p. 260.




CHAPTER VI



DEVELOPMENTS OF THE INDORE PROCESS


GREEN-MANURING

Since Schultz-Lupitz first showed about 1880 how the open sandy soils of
North Germany could be improved in texture and in fertility by the
incorporation of a green crop of lupine, the possibilities of this method
of enriching the land have been thoroughly explored by the Experiment
Stations. After the role of the nodules on the roots of leguminous plants
in the fixation of atmospheric nitrogen was proved, the problems of
green-manuring naturally centred round the utilization of the leguminous
crop in adding to the store of combined nitrogen and organic matter in
the soil. At the end of the nineteenth century it seemed so easy, by
merely turning in a leguminous crop, to settle at one stroke and in a
very economical fashion the great problem of maintaining soil fertility.
At the expenditure of a little trouble, the leguminous nodule might be
used as a nitrogen factory while the remainder of the crop could provide
humus. All this might be accomplished at small expense and without any
serious interference with ordinary cropping. These expectations, a
natural legacy of the NPK mentality, have led to innumerable
green-manuring experiments all over the world with practically every
species of leguminous crop. In a few cases, particularly in open,
well-aerated soils where the rainfall after the ploughing in of the green
crop was well distributed and ample time was given for decay, the results
have been satisfactory. In the majority of cases, however, they have been
disappointing. It will be useful, therefore, to examine the whole subject
and to determine if possible the reasons why this method of improving the
fertility of the soil seems so often to have failed.

A consideration of the factors involved in the growth, decay, and
utilization of the residues of a green crop will at once explain the
general failure of green-manuring to increase the following crop and also
put an end for all time to the somewhat extravagant hopes of repeating
the German results, which succeeded because all the factors, including
time, happened to be favourable. It is no use slavishly copying this
method unless we can at the same time reproduce the North German soil and
climatic conditions.

The chief factors in green-manuring are: (1) knowledge of the nitrogen
cycle in relation to the local agriculture; (2) the conditions necessary
for rapid growth and also for the formation of abundant nodules on the
roots of the leguminous crop used for green-manuring; (3) the chemical
composition of the green crop at the moment it is ploughed in; (4) the
soil conditions during the period when decay takes place. These four
factors must be studied before the possibilities of green-manuring can be
explored.

The importance of the nitrogen cycle in relation to the local agriculture
is a factor in green-manuring to which far too little attention has been
paid. As will be shown more fully in Chapter XIV, the full possibilities
of green-manuring can only be utilized when we know at what periods of
the year nitrate accumulations take place, how these accumulations fit in
with the local agricultural practice, and when nitrates are liable to be
lost by leaching and other means. If the crop does not make the fullest
use of nitrate, this precious substance must be immobilized by means of
green-manure or by means of weeds and algae. It must not be left to take
care of itself. It must either be taken up by the crop or banked by some
other plant.

The soil conditions necessary for the growth of the leguminous crop used
as a green-manure have never been sufficiently studied. Clarke found at
Shahjahanpur in India that it was advantageous to apply a small dressing
of farm-yard manure to the land just before the green crop is sown. The
effect of this is to stimulate growth and nodular development in a
remarkable way. Further, the green crop when turned in decays much faster
than when this preliminary manuring is omitted. It may be that besides
stimulating nodular development the small dressing of farm-yard manure is
necessary to bring into effective action the mycorrhizal association
which is known to exist in the roots of most leguminous plants. This
association is a factor which has been completely forgotten in
green-manuring. There is no reference to it in Waksman's excellent
summary on pp. 208-14 of the last edition of his monograph on humus. This
factor will probably also prove to be important in the utilization of the
humus left by green-manuring.

The living bridge between the humus in the soil and the plant must be
properly fed, otherwise the nutrition of the crop we wish to benefit is
almost certain to suffer.

As growth proceeds the chemistry of a green crop alters very
considerably: the material in a young or in a mature crop, when presented
to the micro-organisms of the soil, leads to very different results.
Waksman and Tenney have set out the results of the decomposition of a
typical green-manure plant (rye) harvested at different periods of
growth. When the plants are young they decompose rapidly: a large part of
the nitrogen is released as ammonia and becomes available. When the
plants are mature they decompose much more slowly: there is insufficient
nitrogen for decay, so the micro-organisms utilize some of the soil
nitrates to make up the deficiency. Instead of enriching the soil in
available nitrogen the decay of the crop leads to temporary
impoverishment. These fundamental matters are summed up in the following
Table:


TABLE 5

Rapidity of decomposition of rye plants at different stages of growth
(Waksman and Tenney)

Two grammes of dry material decomposed for 27 days

Stage of growth   CO2 given off  Nitrogen liberated  Nitrogen cnsumed from
                    (mg. C)       as ammonia (mg. N)    the media(mg. N)

Plants only
25-35 cm. high       286.8               22.2                    0

Just before heads
begin to form        280.4                3.0                    0

Just before bloom    199.5                  0                    0

Plants nearly
mature               187.9                  0                  8.9


The amount of humus which results from the decay of a green crop also
depends on the age of the plants. Young plants, which are low in lignin
and in cellulose, leave a very small residue of humus. Mature plants,
on the other hand, are high in cellulose and lignin and yield a large
amount of humus. These differences are brought out in Table 6.

It follows from these results that if we wish to employ green-manuring
to increase the soil nutrients quickly, we must always plough in the
green crop in the young stage; if our aim is to increase the humus content
of the soil we must wait till the green-manure crop has reached its
maximum growth.

The soil conditions after the green crop is ploughed in are no less
important than the chemical composition of the crop. The micro-organisms
which decay the green-manure require four things: (1) sufficient combined
nitrogen and minerals; (2) moisture; (3) air; (4) a suitable temperature.
These must all be provided together.


TABLE 6

Formation of humus during decomposition of rye plants at different stages
of development

(Waksman and Tenney)

Chemical constituents   At beginning of    At the end of    At the end of
                        decomposition*     decomposition   decomposition**
                             mg.               mg.           % of original

JUST BEFORE HEADS BEGIN TO FORM

Total water-insoluble
organic matter             7,465               2,015              27.0
Pentosans                  2,050                 380              18.5
Cellulose                  2,610                 610              23.4
Lignin                     1,180                 750              63.6
Protein insoluble
in water                     816                 253              31.0

PLANTS NEARLY MATURE

Total water-insoluble
organic matter           15,114                8,770              58.0
Pentosans                 3,928                1,553              39.5
Cellulose                 6,262                2,766              44.2
Lignin                    3,403                3,019              88.7
Protein insoluble
in water                    181                  519             286.7

* 10 gm. material (on dry basis) used for young plants and 20 gm.
for old plants.
** 30 days for young plants and 60 days for mature plants.


The factor which so often leads to trouble is the poverty of the
soil--insufficient combined nitrogen and minerals. It follows, therefore,
that when a mature crop is ploughed in the effect of its decay on the
next crop will always depend on the fertility of the soil. If the soil is
in a poor condition most of the combined nitrogen available will be
immobilized for the decay of the green-manure; the next crop will suffer
from starvation; green-manuring will then be a temporary failure. If,
however, the soil is fertile or if we plough in freshly prepared humus
with the green crop, the extra combined nitrogen needed for decay will
then be present; the next crop will not suffer. Soil fertility in this,
as in so many other matters, gives the farmer considerable latitude. All
sorts of things can be done with perfect safety with a soil in good heart
which are out of the question when the soil is infertile. A good reserve
of fertility, therefore, will always be an important factor in
green-manuring.

As the decomposition of a green crop is carried out by microorganisms,
decay ceases if the moisture falls below a certain point.

Again, if the air supply is cut off by excessive rain after ploughing in
or by burying the green crop too deeply, an anaerobic soil flora rapidly
develops which proceeds to obtain its oxygen supply from the substratum.
The valuable proteins are attacked and their nitrogen is released as gas.
The chemical reactions of the peat bog replace those of the early stages
of a properly managed compost heap. This frequently happens under monsoon
conditions and is one of the reasons why green-manuring is so often
unsatisfactory in tropical agriculture.

Finally, the temperature factor is important in countries like Great
Britain which have a winter. Here green-manure crops must often be turned
in during the autumn before the soil gets too cold, so that the early
stages of decay can be completed before winter comes.

The uses of green-manuring in agriculture can now be considered.
Generally speaking they fall into three classes: (1) the safeguarding of
nitrate accumulations; (2) the production of humus, and (3) a combination
of both.


THE SAFEGUARDING OF NITRATE ACCUMULATIONS

In studying this important matter we must at the outset consider how
Nature, if left to herself, always deals with the nitrates prepared from
organic matter by the micro-organisms in the soil. They are never allowed
to run to waste but are immobilized by plants including the film of algae
in the surface soil. These latter are easily decomposed: they are
therefore exceedingly valuable agencies for safeguarding nitrates.

The farmer has at his command two methods of nitrate immobilization. He
can either intercept his surplus nitrate accumulations by sowing a
leguminous crop or by managing his weeds and soil algae so that they do
the same thing automatically. In either case nitrates which would
otherwise run to waste are converted into young fresh growth which cannot
then be lost by leaching and which later on can be rapidly converted back
into available nitrogen and minerals by the organisms in the soil.
Obviously if weeds can be managed so that all nitrate accumulations can
be utilized and the resulting growth can be turned under and decomposed
in time for the next crop, there is no need to sow a leguminous crop to
do what Nature herself can do so much better.

One of the best examples I have seen of the combined use of weeds and
catch crops for immobilizing nitrates was worked out by Mr. L. P. Haynes
on the large hop garden of Messrs. Arthur Guinness, Son & Co. at Bodiam
in Sussex. Surface cultivation in this garden ceases in August soon after
the hops form. A little mustard is then sown which, with the chickweed,
soon produces a green carpet without interfering with the ripening of the
hops. At picking time the mixed seedlings are well established, after
which they have the nitrates formed at the end of the summer and in early
autumn entirely to themselves. Growth is very rapid. During the autumn
sheep are brought in to graze the mustard. Their urine and dung fall on
the chick-weed and so contribute a portion of the essential animal
wastes. In the spring the easily decomposed chickweed is ploughed into
the fertile soil and decayed in good time for the next crop of hops. The
soil of this hop garden is now heavily charged with chickweed seeds so
that the moment surface cultivation is stopped the following August a new
crop starts. This management of a common weed of fertile soil to fit in
with the needs of the hop appeared to me to be nothing short of a stroke
of genius. It would be difficult to find a more efficient green-manure
crop than the one Nature has provided for nothing. Could there be a
better example of the use of a fertility reserve for rapidly decomposing
a green crop in the early spring? The ground at Bodiam is hardly ever
uncovered; it is occupied either by hops or by chickweed; one crop
dovetails into the other; the energy of sunlight is almost completely
utilized throughout the year; the invisible labour force of the hop
garden--earthworms and micro-organisms--is kept fully occupied. As the
use of artificials and poison sprays is reduced, there will be a
corresponding increase in efficiency in this section of the unseen
establishment.

Much more use might be made of this method of green-manuring in
countries like Great Britain. In fruit, vegetable, and potato growing
particularly, there seems no reason why an autumn crop of weeds should
not be treated as green-manure on Bodiam lines. If the land is in good
heart, the soil will have no difficulty in decaying the weeds. If the
land is poor in organic matter, a dressing of freshly prepared humus of
not less than 5 tons to the acre should be spread on the weeds before
they are turned under.


THE PRODUCTION OF HUMUS

The production of humus, by means of a green-manure crop, is a much more
difficult matter than the use of this method for immobilizing nitrates.
Nevertheless, it is of supreme importance in the maintenance of soil
fertility. The factors involved in the transformation of green-manure
into humus in the soil are the same as those in the compost heap. All
factors must operate together. Failure of one will upset the process
entirely. If this occurs the next crop will be sown in soil which has
been placed in an impossible condition. The land will be called upon to
complete the formation of humus and to grow a crop at the same time. This
is asking too much. The soil will take up its interrupted task and
proceed with the manufacture of humus. It will neglect the crop. The
uncontrollable factor is the rainfall. It must be just right if humus
manufacture in the soil is to succeed. In India, for example, during an
experience of twenty-six years it used to be just right about once in six
or seven years. It was completely wrong in the remainder. Often there was
too much rain after ploughing in, when the aerobic phase never developed
and bog conditions were established instead. At other times there was
insufficient rain for the early fungous stage. Where, however, irrigation
is available, any shortage of the Indian monsoon makes no difference.

In exceptional cases, however, it is possible to carry on the manufacture
of humus in the soil without any risk of temporary failure. One British
example may be quoted. On some of the large farms in the Holland Division
of Lincolnshire peas are grown as a rotation crop with potatoes. The
problem is to manufacture humus before the next crop of potatoes is
planted. This has been solved. Early in July the peas are cut and carried
to the shelling machines where the green seeds are separated and large
quantities of crushed haulm are left. Immediately after the removal of
the peas the land is sown with beans. The crushed pea haulm is then
scattered on the surface of the newly sown land followed by a light
dressing of farm-yard manure--about 6 or 7 tons to the acre. The beans
grow through the fermenting layer on the surface of the soil and help to
keep it moist. While the beans are growing humus is being manufactured in
a thin sheet all over the field. At the end of September, when the beans
are in flower, this sheet composting on the ground is complete. The green
crop is then lightly ploughed in together with a layer of freshly
prepared compost. Humus manufacture is then continued in the soil. The
beans under these conditions decay quickly; the process of humus
manufacture is completed before the planting of the next potato crop.


THE SAFEGUARDING OF NITRATES FOLLOWED BY THE MANUFACTURE OF HUMUS

The immobilization of nitrates by means of a green crop followed by the
conversion of the green-manure into humus needs time and complete control
of all the operations. An example of the successful use of this method is
described in Chapter XIV. Heavy crops of sugar-cane were produced at
Shahjahanpur in the United Provinces by intercepting the nitrates
accumulated at the break of the south-west monsoon by means of a
leguminous crop and then converting this into humus with the assistance
of the autumn accumulation of nitrate in the same soil.

It follows from the principles underlying green-manuring and the
applications of these principles to agricultural practice that the
ploughing in of a green crop is not a simple question of the addition of
so many pounds of nitrogen to the acre but a vast and many-sided
biological problem. Moreover it is dynamic, not static; the agents
involved are alive; their activities must fit in with one another, with
agricultural practice on the one hand and with the season on the other.
If we attempt to solve such a complex on the basis of mere nitrogen
content or on that of carbon: nitrogen ratios, we are certain to run
counter to great biological principles and come into conflict with one
rule in Nature after another. It is little wonder, therefore, that
green-manuring has led to so much misunderstanding and to so much
disappointment.


THE REFORM OF GREEN-MANURING

The uncertainties of humus manufacture in the soil can be overcome by
growing the green crop to provide material for composting. This of course
adds to the labour and the expense, but in many countries it is proving a
commercial proposition. In Rhodesia, for example, crops of salt hemp are
now regularly grown to provide litter, rich in nitrogen, for mixing with
maize stalks so as to improve the carbon: nitrogen ratio of the bedding
used in the cattle kraals. In this way the burden on the soil is greatly
reduced; it is only called upon to decay what is left of the root system
of the green crop at harvest time. Humus manufacture is shared between
the soil and the compost heap.

In converting materials low in nitrogen (such as sugar-cane leaves and
cotton stalks) into humus it is an immense advantage to mix these
refractory materials with some leguminous plant in the green state. The
manufacture of humus is speeded up and simplified; the amount of water
needed is reduced; the land on which the green crop was raised benefits.



BIBLIOGRAPHY

CLARKE, G. 'Some Aspects of Soil Improvement in relation to Crop
Production', Proc. of the Seventeenth Indian
Science Congress, Asiatic Society of Bengal, Calcutta, 1930, p. 23.

WAKSMAN, S. A., and TENNEY, F. G. Composition of Natural Organic Materials
and their Decomposition in the Soil,
Soil Science, xxiv, 1927, p. 275; xxviii, 1929, p. 55; and xxx,
1930, p. 143.




CHAPTER VII



DEVELOPMENTS OF THE INDORE PROCESS


GRASS-LAND MANAGEMENT

Two very different methods of approach to the problems of grass-land
management in a country like Great Britain are possible. We can either
study the question from the point of view of the present organization of
agricultural research in this country or we can bring the world-wide
experience of the grass and clover families to bear as if no institutions
like the Welsh Plant Breeding Station, the Rowett Institute at Aberdeen,
or the Rothamsted Experiment Station--all of which deal independently
with some fragment of the grass-land problem--had ever been contemplated.
As the advantages of the fresh eye are many and obvious and as the writer
has had a long and extensive first-hand experience of the cultivation of
a number of crops belonging to the grass and clover families, the
principles underlying grass-land management in Great Britain will be
considered from a new angle, namely, the conditions which practical
experience in the tropics has shown to be necessary for grasses and
legumes to express themselves and to tell their own story.

The grass and clover families are widely distributed and cultivated all
over the world--from the tropics to the temperate zones and at all
elevations and under every possible set of soil and moisture
conditions--either as separate crops or more often mixed together.
Everywhere the equivalent of the short ley, composed of grasses and
legumes, is to be found. The successful mixed cultivation of these two
groups of plants has been in operation for many centuries: in the Orient
they were grown together in suitable combinations long before England
emerged from the primitive condition in which the Roman invaders found
it--an island covered for the most part with dense forests and impassable
bogs.

What are the essential requirements of the grass and clover families?
The clearest answer to this question is supplied by tropical agriculture;
here the growth factors impress themselves on the plant much more
definitely and dramatically than they do in a damp temperate island like
Great Britain where all such reactions are apt to be very much toned down
and even blurred.

Sugar-cane, maize, millets, and the dub grass of India (Cynodon dactylon
Pers.) are perhaps the most widely cultivated and the most suitable
grasses for this study. Lucerne, san hemp (Crotalaria juncea L.), the
cluster bean (Cyamopsis psoralioides D.C.), and the pigeon pea (Cajanus
indices Spreng.) are corresponding examples of the clover family. The
last two of these are almost always grown mixed either with millets or
maize, very much in the same way as red clover and rye-grass are sown
together in Great Britain.

The grass family must first be considered. A detailed account of the
cultivation of the sugar-cane will be found in a later chapter. Humus and
ample soil aeration, combined with new varieties which suit the improved
soil conditions, enable this grass to thrive, to resist disease, and to
produce maximum yields and high quality juice without any impoverishment
of the soil. Maize behaves in the same way and is perhaps one of our best
soil analysts. Any one who attempts to grow this crop without organic
matter will begin to understand how vital soil fertility is for the grass
family. The requirements of the dub grass in India, one of the most
important fodder plants of the tropics, are frequent cultivation and
abundance of humus. The response of this species to a combination of
humus and soil aeration is even more remarkable than in maize: once these
factors are in defect growth stops. The behaviour of dub grass, as will
be seen later on, indicates clearly what all grasses the world over need.

Any one who grows lucerne in India under irrigation will court certain
failure unless steps are taken to keep the crop constantly supplied with
farm-yard manure and the aeration of the surface soil at a high level.
When suitable soil conditions are maintained it is possible to harvest
twenty or more good crops a year. Once the surface soil is allowed to
pack and regular manuring is stopped, a very different result is
observed. The number of cuts falls off to three or four a year and the
stand rapidly deteriorates. When san hemp is grown for green-manuring or
for seed in India satisfactory results are only obtained if the crop is
manured with cattle manure or humus. These two leguminous crops do not
stand alone. Every member of this group I have grown responds at once to
farmyard manure or humus. But all this is not in accordance with theory.

According to the text-books the nodules in the roots of leguminous plants
should be relied on to furnish combined nitrogen and this group should
not need nitrogenous manure. Practical experience and theory are so wide
apart as to suggest that some other factor must be in operation. It was
not till January 1938 that I discovered what this factor was. On the
Waldemar tea estate in Ceylon I saw a remarkable crop of a green-manure
plant--Crotalaria anagyroides--growing in soil rich in humus. The root
development was exceptional: an examination of the active roots showed
that they were heavily infected with mycorrhiza. Other tropical
leguminous plants growing in similar soils also exhibited the mycorrhizal
association. So did several species of clover collected in France and
Great Britain. These results at once suggested the reason why san hemp,
lucerne, and many other tropical legumes respond so strikingly to cattle
manure. They must all be mycorrhiza-formers.

The fact that leguminous plants and grasses respond to the same factors
and that the former group are mycorrhiza-formers suggested that this
association would also be found in the grasses. Sugar-cane was first
investigated. It proved to be a mycorrhiza-former. The grasses of the
meadows and pastures of France and Great Britain were then studied. The
herbage of the celebrated meadows of La Frau, between Salon and Arles in
Provence, was examined for mycorrhiza in 1938 and again in 1939. In both
seasons the roots of the grasses were found to be infected with
mycorrhiza. Dr. Levisohn's report on the samples collected in July 1939
reads as follows: 'Sporadic but deep infection of the long and short
roots: coarse mycelium inter-and intra-cellular: digestion stages: the
products of digestion seem to be translocated rapidly.' In the material
from La Crau examined in 1939 the most remarkable example of the
mycorrhizal relationship occurred in a species of Taraxacum which formed
at least a quarter of the herbage. Here the infection of the inner layers
of the long and short roots was 'very widespread and deep. The mycelium
is of large diameter, thin-walled with granular contents. Distribution
mainly intra-cellular. Digestion showing all stages of disintegration.
Root hairs sparsely formed. The mycorrhizal regions of the roots are
indicated macroscopically by beading, greater opacity, and slight
yellowing of the infected zones' (Levisohn). This suggests that some or
all of the so-called weeds of grass-land may well play an important role
in the transmission of quality from soil to plant and in the nutrition of
the animal. Samples of the turf from two well-known farms in England--Mr.
Hosier's land in Wiltshire and Mr. William Kilvert's pastures in Corve
Dale in Shropshire--were then examined. They gave similar results to
those of La Crau. Clearly the grass family, like the clover group, are
mycorrhiza-formers, a fact which at once explains why both these classes
of plants respond so markedly to humus.

This independent approach to the grass-land problems of countries like
Great Britain has brought out new principles. Grasses and clovers fall
into one group as regards nutrition and not, as hitherto thought, into
two groups. Both require the same things--humus and soil aeration. Both
are connected with the organic matter in the soil by a living fungous
bridge which provides the key to their correct nutrition and therefore to
the management of grass-land. If this view is a sound one it follows that
any agency which will increase the natural formation of humus under the
turf of our grass-lands will be followed by an improvement in the herbage
and by an increase in their stock-carrying capacity. The methods which
increase humus formation in the soil must now be considered. The
following may be mentioned:

1. The bail system. The most spectacular example of humus manufacture in
the soil underneath a pasture is that to be seen on Mr. Hosier's land on
the downs near Marlborough. By a stroke of the pen, as it were, he
abolished the farm-yard, the cowshed, and the dung-cart in order to
counter the fall in prices which followed the Great War. He reacted to
adversity in the correct manner: he found it a valuable stimulant in
breaking new ground. The cows were fed and made to live out of doors.
They were milked in movable bails. Their urine and dung were
systematically distributed at little cost over these derelict pastures.
The vegetable residues of the herbage came in contact with urine, dung,
air, water, and bases. The stage was set for the Indore Process. Mr.
Hosier's invisible labour force came into action: the micro-organisms in
the soil manufactured a sheet of humus all over the downs: the earthworms
distributed it. The roots of the grasses and clovers were soon geared up
with this humus by means of the mycorrhizal association. The herbage
improved; the stock-carrying capacity of the fields went up by leaps and
bounds. Soil fertility accumulated; every five years or so it was cashed
in by two or three straw crops; another period under grass followed, and
so on. Incidentally the health of the animals also benefited; the
prognostications of the neighbourhood (when this audacious innovation
started) that the cows and heifers would soon perish through tuberculosis
and other diseases have not been fulfilled. (Mr. Hosier has done more
than solve a local problem and provide evidence in support of a new
theory. His work has drawn attention to the potential value of our
downlands--areas which in Roman and Saxon times supported a large
proportion of the population of Great Britain.)

2. The use of basic slag. On many of the heavy soils under grass the
limiting factor in humus production is not urine but oxygen. Everything
except air is there in abundance for making humus--vegetable and animal
wastes as well as moisture. Under such turf the land always suffers from
asphyxiation. The soil dies. This is indicated by the absence of nitrates
under such turf. About fifty years ago it was discovered that such
pastures could be improved by dressings of basic slag. As this material
contains phosphate, and as its use stimulates the clovers, it was assumed
that these soils suffered from phosphatic depletion as a result of
feeding a constant succession of live stock, each generation of which
removes so many pounds of phosphate in their bones. When, however, we
examine the turf of a slagged pasture we find that humus formation has
taken place. If the application of slag is repeated on these heavy lands
after an interval of five or six years there is often no further
response. When we apply basic slag to pastures on the chalk there is no
result. There is phosphate depletion on strong lands only at one point;
none at all on light chalk downs. These results do not hold together;
indeed they contradict one another. Are we really dealing with phosphate
deficiency in these lands? May not the humus formed after slag is added
explain the permanent benefit of this manuring? May it not prove that the
effect of slag on heavy soils has been in the first instance a physical
one which has improved the aeration, reduced the acidity, and so helped
humus manufacture to start? We can begin to answer these questions by
studying what happens when the aeration of heavy grass-land is improved
by an alternative method--subsoiling.

3. Sub-soiling. The effect of sub-soiling heavy grasslands was
described by Sir Bernard Greenwell, Bt. in a paper read to the Farmers'
Club on January 30th, 1939, in the following words:


'Taking our grass-land first, probably more can be done by proper
mechanical treatment followed by intensive stocking than by artificial
manuring. Some people are suggesting that we should plough up a lot of
our second-rate pasture land and re-sow it, but this I have found is very
speculative as the cost is in the neighbourhood of 3 to 5 pounds an acre
and the results are bound to be uncertain. By cleaning out ditches,
reopening drains and by mole draining, however, a lot can be done. I have
also found that by using a Ransome mole plough or sub-soiler of the wheel
type, pulled through the land at a depth of 12 inches to 14 inches, 4
feet apart, one can produce much better grass, and this is proved by the
greatest expert of all--the animal. In a field which was partly
sub-soiled we found that this sub-soiled part was grazed hard by the
cattle, and the part that was not treated in this way was only lightly
picked over. The cost of this is about 2s. 6d. per acre without overheads
and lost time. We reckon 1 pound a day for a 40-h.p. tractor, including
labour, depreciation, etc., and a tractor will do 9 to 10 acres a day
sub-soiling at 4 feet intervals.'


Poor aeration was obviously the limiting factor at Marden Park. Once this
was removed humus formation started and the herbage improved. It will be
interesting to watch the results of the next stage of this work. Half of
a sub-soiled field has been dressed with basic slag and the reaction of
the animals is being watched. If they graze the field equally, basic slag
is probably having no effect: if the animals prefer the slagged half then
this manure is required. (The Marden Park results suggest a further
question. Will sub-soiling at 2s. 6d. an acre replace the ploughing-up
campaign recently launched by the Ministry of Agriculture for which the
State pays 2 pounds an acre? If, as seems likely, the basic slag and
ploughing-up subsidies are both unnecessary, a large sum of money will be
available for increasing the humus of the soils of Great Britain, the
need for which requires no argument.)

4. The cultivation of grass-land. One of the recommendations of the Welsh
Plant Breeding Station is the partial or complete cultivation of
grass-land. Partial cultivation is done from the surface by various types
of harrow: complete cultivation by the plough. In both cases aeration is
improved; the production of humus is stimulated; generally speaking the
result obtained is in direct proportion to the degree of cultivation;
ploughingup and reseeding is far better for the grass than mere
scarification with harrows. In this work we must carefully distinguish
the means and the end. The agency is some form of cultivation; the
consequence is always the manufacture of humus.

It will be evident that the various methods by which humus is
manufactured under the growing turf itself or by ploughing up and rotting
the old turf agree in all respects with what is to be learned from the
grasses and the legumes of the tropics. Sir George Stapledon's advice as
regards Great Britain is supported by the age-long experience of the
agriculture of the East. No stronger backing than this is possible. There
is only one grass-land problem in the world. It is a simple one. The soil
must be brought back to active life. The micro-organisms and earthworms
must be supplied with freshly made humus and with air. Varieties of
grasses and legumes which respond to improved soil conditions must then
be provided. In this way only can the farmers of Great Britain make the
most of our green carpet. Our grass-lands will then be able to do what
Nature does in the forest--manure themselves.

The order in which improvements should be introduced in grass-land
management is important. Soil fertility must first be increased so that
the grasses and clovers can fully express themselves. Improved varieties
should then be selected to suit the new soil conditions. If we study the
variety by itself without any reference to the soil and develop higher
yielding strains of grasses and clovers for the land as it is now, there
is a danger, indeed almost a certainty, that the farmer will be furnished
with yet another means of exhausting his soil. The new varieties will
have a short life: they will prove to be a boomerang: the last state of
the farm will be worse than the first. If, however, the soil conditions
are first improved and the system of farming is such that soil fertility
is maintained, the plant breeder will be provided with a safe field for
his activities. His work will then have a permanent value.

How are we to test the fertility of grass-land? Mr. Hosier has supplied
the answer. Grass-land can be tested for fertility by means of a complete
artificial manure. If the soil is really fertile, such a dressing will
give no result, because no limiting factor in the shape of shortage of
nitrogen, phosphorus, or potash exists. Mr. Hosier has summed up his
experience of this matter in a letter dated Marlborough, April 6th, 1938,
as follows:


'On my improved grass-land, I have on several occasions put down
experimental plots of artificial manures and there was no response even
where there Divas a complete fertilizer applied. Before I started
open-air dairying on a big scale in 1924, I put down 150 plots and in
many places I could write my name with artificials.'


The value of this experience does not end with the testing of soil
fertility. It indicates the very high proportion of the grasslands of
western Europe which are infertile and which need large volumes of humus
to restore their fertility. Most of the fields under grass will respond
to artificials. All these are infertile.

The consequences of the improvement of grass-land in a country like Great
Britain can now be summarized. The land will carry more live stock. The
surplus summer grass can be dried for winter feeding. The stored
fertility in the pastures can be cashed in at any time in the form of
wheat or other cereals. A valuable food reserve in time of war will
always be available. As Mr. Hosier has shown, there will be no damage
from wireworms when such fertile pastures are broken up and sown with
wheat.



BIBLIOGRAPHY

GREENWELL, SIR BERNARD. Soil Fertility: The Farm's Capital, Journal
of the Farmers Club, 1939, p. 1.

HOSIER, A. J. 'Open-air Dairying', Journal of the Farmers' Club,
1927, p. 103.

HOWARD, A. Crop Production in India: A Critical Survey of its Problems,
Oxford University Press, 1924.

STAPLEDON, R. G. The Land, Now and To-morrow, London, 1935.




CHAPTER VIII



DEVELOPMENTS OF THE INDORE PROCESS


THE UTILIZATION OF TOWN WASTES

The human population, for the most part concentrated in towns and
villages, is maintained almost exclusively by the land. Apart from the
harvest of the sea, agriculture provides the food of the people and the
requirements of vegetable and animal origin needed by the factories of
the urban areas. It follows that a large portion of the waste products of
farming must be found in the towns and away from the fields which
produced them. One of the consequences, therefore, of the concentration
of the human population in small areas has been to separate, often by
considerable distances, an important portion of the wastes of agriculture
from the land. These wastes fall into two distinct groups:

(a) Town wastes consisting mainly of the contents of the dustbins,
market, street, and trade wastes with a small amount of animal manure.

(b) The urine and faeces of the population.

In practically all cases in this country both groups of waste materials
are treated as something to be got rid of as quickly, as
unostentatiously, and as cheaply as possible. In Great Britain most town
wastes are either buried in a controlled tip or burnt in an incinerator.
Practically none of our urban waste finds its way back to the land. The
wastes of the population, in most Western countries, are first diluted
with large volumes of water and then after varying amounts of
purlfication, are discharged either into rivers or into the sea. Beyond a
little of the resulting sewage sludge the residues of the population are
entirely lost to agriculture.

From the point of view of farming the towns have become parasites. They
will last under the present system only as long as the earth's fertility
lasts. Then the whole fabric of our civilization must collapse.

In considering how this unsatisfactory state of affairs can be remedied
and how the wastes of urban areas can be restored to the soil, the
magnitude of the problem and the difficulties which have to be overcome
must be realized from the outset. These difficulties are of two kinds:
those which belong to the subject proper, and those inherent in
ourselves. The present system of sewage disposal has been the growth of a
hundred years; problem after problem has had to be solved as it arose
from the sole point of view of what seemed best for the town at the
moment; mother earth has had few or no representatives on municipal
councils to plead her cause; the disposal of waste has always been looked
upon as the sole business of the town rather than something which
concerns the well-being of the nation as a whole. The fragmentation of
the subject into its urban components--medical, engineering,
administrative, and financial--has followed; direction has been lost. The
piecemeal consideration of such a matter could only lead to failure.

Can anything be done at this late hour by way of reform? Can mother earth
secure even a partial restitution of her manurial rights? If the easiest
road is first taken a great deal can be accomplished in a few years. The
problem of getting the town wastes back into the land is not difficult.
The task of demonstrating a working alternative to water-borne sewage and
getting it adopted in practice is, however, stupendous. At the moment it
is altogether outside the bounds of practical politics. Some catastrophe,
such as a universal shortage of food followed by famine, or the necessity
of spreading the urban population about the country-side to safeguard it
from direct and indirect damage by hostile aircraft, will have to be upon
us before such a question can even be considered.

The effective disposal of town wastes is, however, far less difficult, as
will be seen by what has already been accomplished in this country.
Passing over the earlier experiments with town wastes, summed up in a
recent publication of the Ministry of Agriculture (Manures and Manuring,
Bulletin 36, Ministry of Agriculture and Fisheries, H.M. Stationery
Office, 1937), in which the dustbin refuse was used without modification,
the recent results obtained with pulverized wastes, prepared by passing
the sorted material (to remove tin cans, bottles, and other refractory
objects) through a hammer mill, point clearly to the true role of this
material in agriculture. Its value lies, not in its chemical composition,
which is almost negligible, but in the fact that it is a perfect diluent
for the manure heap, the weakest link in agriculture in many countries.
The ordinary manure heap on a farm is biologically unbalanced and
chemically unstable. It is unbalanced because the micro-organisms which
are trying to synthesize humus have far too much urine and dung and far
too little cellulose and lignin and insufficient air to begin with. It is
unstable because it cannot hold itself together; the valuable nitrogen is
lost either as ammonia or as free nitrogen; the micro-organisms cannot
use up the urine fast enough before it runs to waste; the proteins are
used as a source of oxygen with the liberation of free nitrogen. The
fungi and bacteria of the manure heap are working under impossible
conditions. They live a life of constant frustration which can only be
avoided by giving them a balanced ration. This can be achieved by
diluting the existing manure heaps with three volumes of pulverized town
wastes. The micro-organisms are then provided with all the cellulose and
lignin they need. The dilution of the manure heap automatically improves
the aeration. The volume of the resulting manure is multiplied by at
least three; its efficiency is also increased.

Such a reform of the manure heap is practicable. Two examples may be
quoted. At the large hop garden at Bodiam in Sussex, the property of
Messrs. Arthur Guinness, Son & Co., Ltd., over 30 tons of pulverized town
wastes from Southwark are used daily throughout the year for humus
manufacture. This material is railed in 6-ton truck-loads to Bodiam,
transferred to the hop gardens by lorry and then composted with all the
wastes of the garden--hop vine, hop string, hedge and roadside trimmings,
old straw, all the farm-yard manure which is available--and every other
vegetable and animal waste that can be collected locally. The annual
output of finished humus is over 10,000 tons, which is prepared at an
all-in cost of 10s. a ton, including spreading on the land. The Manager
of this garden, Mr. L. P. Haynes, has worked out comparative figures of
cost between nitrogen, phosphorus, and potash applied in the form of
humus or artificials. The cost of town wastes for Bodiam is 4s. 6d. a
ton; lorry transport from rail to garden 3s. a ton; assembling and
turning the compost heaps and spreading on the land 2s. 6d. a ton. The
analysis of this humus was: 0.96 per cent. nitrogen, 2.45 per cent.
phosphate, and 0.62 per cent. potash. Sixteen tons of humus therefore
contain 344 lb. of nitrogen, 769 lb. of P205, and 222 lb. of K2O. The
cost of this at 10s. a ton including spreading comes to 8 pounds an acre.
The purchase, haulage, and sowing of these amounts of NPK in the form of
sulphate of ammonia, basic slag, and muriate of potash comes to 9 pounds
12s. 7-1/2d. There is therefore a distinct saving when humus is used.
This, however, is only a minor item on the credit side. The texture of the
soil is rapidly improving, soil fertility is being built up, the need for
chemical manures and poison sprays to control pests is becoming less.

The manurial policy adopted on this hop garden has been confirmed in
rather an interesting fashion. Before a serious attempt was made to
prepare humus on the present scale, a small amount of pulverized
Southwark refuse had been in use. The bulk of the manure used, however,
was artificials supplemented by the various organic manures and
fertilizers on the market. The labourers employed at Bodiam were
therefore conversant with practically every type of inorganic and organic
manure. One of their privileges is a supply of manure for their gardens.
They have always selected pulverized town wastes because they consider
this grows the best vegetables.

A second large-scale demonstration of the benefits which follow the
reform of the manure heap has been carried out at Marden Park in Surrey.
Many thousands of tons of humus have been made by composting pulverized
town wastes with ordinary dung. In a paper read to the Farmers' Club on
January 30th, 1939, Sir Bernard Greenwell refers to these results as
follows: 'I have only two years' experience of this myself, but from the
results I have seen we can multiply our dung by four and get crops as
good as if the land had been manured with pure dung.' In 1938 I saw some
of this work. Many of the fields on the estate had been divided into
half, one portion being manured with humus and the other with an equal
number of cartloads of dung. I inspected a number of these fields just as
the corn was coming into ear. In every case the crops grown with
humus--wheat, beans, oats, clover, and so forth--were definitely better
than those raised with farm-yard manure. These results showed that this
land wants freshly prepared humus, not so many lb. to the acre of this
and that. In manuring we are nourishing a complex biological system not
ministering to the needs of a conveyor belt in a factory.

Once the correct use of Southwark wastes was demonstrated a demand for
this material arose. The sales increased; the demand now exceeds the
supply. The details are given in Table 7.


TABLE 7

Sales of crushed wastes at Southwark

Year       Tons crushed*        Tons sold      Income from sales
1933-4    18,643 +12 cwt.     7,971 + 9 cwt.      653/9s/9d
1934-5    18,620 + 1 cwt.     6,341 + 9 cwt.      482/2s/7d
1935-6    19,153 + 14 cwt.    9,878 + 5 cwt.   1,001/11s/1d
1936-7    18,356 + 13 cwt.   12,760 + 15 cwt.    1845/6s/8d
1937-8    18,545 + 15 cwt.   15,391 + 8 cwt.   2,306/13s/7d
1938-9    17,966 + 3 cwt.    17,052 + 1 cwt.   2,715/14s/8d

* A certain amount of these wastes is required by the Depot itself
for sealing one of its own tips; so it is not possible to sell
all the waste crushed to farmers.


When it is remembered that the annual dustbin refuse in Great Britain is
in the neighbourhood of 13,000,000 tons and that about half of this
material can be used for making the most of the urine and dung of our
live stock, it will be evident what enormous possibilities exist for
raising the fertility of the zones of land within, say, fifty miles of
the large cities and towns. A perusal of the Public Cleansing Return for
the year ending March 31st, 1938, published by the Ministry of Health,
shows that a certain proportion of this dustbin refuse is still burnt in
incinerators. Once, however, the agricultural value of this material is
realized by farmers and market gardeners it will not be long before
incineration is given up and the whole of the organic matter in our town
wastes finds its way into the manure heap. When this time comes the
utilization of the enormous dumps of similar wastes, which accumulated
before controlled tipping was adopted, can be taken in hand. These
contain many more millions of tons of material which can be dealt with on
Southwark lines. In this way the manure heaps of a very large portion of
rural England can be reformed and the fertility of a considerable area
restored. A good beginning will then have been made in the restitution of
the manurial rights owing to the country-side. The towns will have begun
to repay their debt to the soil.

Besides the wastes of the dustbins and the dumps there is another and
even more important source of unused humus in the neighbourhood of our
cities and towns. This occurs in the controlled tips in which most of the
dustbin refuse is now buried. In controlled tipping the town wastes are
deposited in suitable areas near cities and sealed with a layer of clay,
soil, or ashes so as to prevent nuisance generally and also the breeding
of flies. The seal, however, permits sufficient aeration for the first
stage in the conversion of most of the organic matter into humus. The
result is that in a year or two the tip becomes a humus mine. The crude
organic matter in these wastes is slowly transformed by means of fungi
and bacteria into humus. All that is needed is to separate the finely
divided humus from the refractory material and to apply it to the land.

A very valuable piece of research work on this matter has recently been
undertaken at Manchester. The results are described by Messrs. Jones and
Owen in Some Notes on the Scientific Aspects of Controlled Tipping,
published by the City of Manchester. The main object of the work was to
establish the facts underlying controlled tipping so that any discussion
on the efficacy of this process, as compared with incineration, could be
conducted on the basis of carefully ascertained knowledge. The
investigation, however, is invaluable from the agricultural standpoint.
The experiments were begun in August 1932 at Wythenshawe in a controlled
tip on a piece of low-lying marshy ground subject to periodic flooding
from the adjacent river Mersey. One of the subsidiary objects of the
tipping was to reclaim the land for recreational or other uses in the
future. Six experimental plots were selected for the tests, each
approximately 16 feet by 12 feet. The material contained in the tip was
ordinary dustbin refuse tipped to a depth of 6 feet. The first object was
to ascertain the consequences of bacterial action on the organic matter
in the interior of the tip, such as the generation of temperature, the
biological as well as the chemical changes, and any alteration in the
gaseous atmosphere in the interior of the mass. Having disposed of these
preliminary matters, it was proposed to attack the main problem and to
answer the question: Is controlled tipping safe?

Careful attention was first given to the seal. The surface of the plots
was covered with a layer of fine dust and ashes, of a minimum thickness
of 6 inches, obtained by passing household refuse over a 3/8 inch mesh.
Such a seal, which contained about 2.5 per cent. of organic matter,
proved to be a suitable mechanical covering and also prevented the
breeding of flies. The sides and ends of the experimental plots were
covered with clay well tamped down. The plots therefore behaved as if
they were large flowerpots in direct contact with the moist earth below
but separated from the outer atmosphere by a permeable seal of screened
dust and fine ashes.

The unsorted household refuse under experiment represented an average
sample and contained about 42 per cent. of organic matter, the remaining
58 per cent. being composed of inorganic materials. After tipping and
sealing, there was a rapid rise of temperature, irrespective of the
season, to a maximum of 160 degrees F. towards the end of the first week.
This was caused by the activities of the thermogenic and thermophyllic
members of the aerobic group of bacteria which break down cellulose,
liberate heat, and produce large volumes of carbon dioxide. At the same
time these organisms rapidly multiply and in so doing synthesize large
amounts of protein from the mixed wastes. This on the death of the
organisms forms a valuable constituent of the humus left when the
bacterial activities die down after about fifteen weeks, as is indicated
by the return of the temperature of the tip to normal. The controlled tip
therefore behaves very much like an Indore compost heap.

As would be expected from the heterogeneous nature and uneven
distribution of the contents of the tip, considerable variations were
shown in the maximum temperatures attained. During the period of
fermentation the bacterial flora (at first aerobic) use and reduce the
oxygen content of the tip, and so pave the way for the facultative
anaerobic organisms which complete the conversion of the organic matter
into humus.

A detailed examination of the gases produced in the tips showed that in
addition to nitrogen, carbon dioxide, and oxygen, a considerable quantity
of methane (16 per cent.) and smaller proportions of carbon monoxide (2.8
per cent.) and hydrogen (2.5 per cent.) occurred. Traces only of
sulphuretted hydrogen were detected. The presence of carbon monoxide,
methane, and hydrogen would naturally result from the anaerobic
fermentation which establishes itself in the second stage of the
production of humus after the free oxygen in the tip becomes exhausted.
These gases are similar to those produced by the decay of organic matter
in swamp rice cultivation in India, where the supply of oxygen is almost
always in defect. The absence of anything beyond a trace of sulphuretted
hydrogen is reassuring, as this proves that the intense reduction which
precedes the formation of the salts of alkali soils does not occur in a
controlled tip.

The manurial value of the humus in the tips was determined by analysis
and valuation. The average content of nitrogen was 0.8 per cent., of
phosphoric acid 0.5 per cent., of potash 0.3 per cent. The estimated
value of the dry material per ton was 10s. This value, however, will have
to be multiplied by a factor ranging from 2 to 2.5, because experience
has shown that the market price of organic manures, based on supply and
demand, is anything from two to two and a half times greater than that
calculated from the chemical analysis. The unit system of valuation
applies only to artificial manures like sulphate of ammonia made in
factories; it does not hold in the case of natural manures like humus.

One of the last sections of the Report relates to the danger of
infectious diseases as a possible consequence of controlled tipping. The
authors conclude that 'danger arising from possible presence of
pathogenic germs in a controlled tip may be dismissed as nonexistent'.

One of the plots, No. 1, not only developed a high temperature but showed
a much more gradual fall than the other plots. This was apparently due to
the higher content of organic matter combined with better aeration. The
results of this plot suggest that more and better humus might be obtained
in a controlled tip if the object of tipping were, as it should be, to
secure the largest amount of humus of the best possible quality. It would
not be a difficult matter to increase the oxygen intake at the beginning
by allowing more and more air to diffuse in from the atmosphere. This
could perhaps be done most easily and cheaply by reducing the thickness
of the seal by about a third. If the seal were reduced in this way, ample
air would find its way into the fermenting mass in the early stages; the
humus would be improved; the covering material saved could be used for a
new seal. The controlled tip would then become a very efficient humus
factory.

In countries where there is no system of water-borne sewage there has
been no difficulty in converting the wastes of the population into humus.
The first trials of the Indore Process for this purpose were completed in
Central India in 1933 by Messrs. Jackson and Wad at three centres near
Indore--the Indore Residency, Indore City, and the Malwa Bhil Corps.
Their results were soon taken up by a number of the Central India and
Rajputana States and by some of the municipalities in India. Subsequent
developments of this work, including working drawings and figures of
cost, were summed up in a paper read to the Health Congress of the Royal
Sanitary Institute held at Portsmouth in 1938. This document has been
reproduced as Appendix C. A perusal of this statement shows that human
wastes are an even better activator than animal residues. All that is
necessary is to provide for abundant aeration in the early stages and to
see that the night soil is spread in a thin film over the town wastes and
that no pockets or definite layers are left. Both of these interfere with
aeration, produce smell, and attract flies. Smell and flies are therefore
a very useful means of control. If the work is properly done there is no
smell, and flies are not attracted because the intense oxidation
processes involved in the early stages of the synthesis of humus are set
in motion. It is only when the air supply is cut off at this stage that
putrefactive changes occur which produce nuisance and encourage flies.

Whether or not it will always be necessary to erect permanent
installations for converting night soil and town refuse into humus,
experience only can decide. In a number of cases it may be easier to do
the composting daily in suitable pits or trenches on the lines described
in Appendix C. In this way the pits or trenches themselves become
temporary composting chambers; no turning is required; the line of pits
or trenches can soon be used for agricultural purposes--for growing all
kings of fodder, cereal, and vegetable crops. At the same time the land
is left in a high state of fertility.

A number of medical officers all over the world are trying out the
composting of night soil on the lines suggested. In a few years a great
deal of experience will be available, on which the projects of the future
can be based.

As far as countries like Great Britain are concerned, the only openings
for the composting of night soil occur in the countryside and in the
outer urban zones where the houses are provided with kitchen gardens. In
such areas the vast quantities of humus in the controlled tips can be
used in earth-closets and the mixed night soil and humus can be lightly
buried in the gardens on the lines so successfully carried out by the
late Dr. Poore and described in his Rural Hygiene, the second edition of
which was published in 1894.

Since Dr. Poore's work appeared a new development in housing has taken
place in the garden cities and in colonies like those started by the Land
Settlement Association. Here, although there is ample land for converting
every possible waste into humus, the water-borne method of sewage
disposal and the dust-carts of the crowded town have been slavishly
copied. In an interesting paper published in the British Medical Journal
of February 9th, 1924, Dr. L. J. Picton, then Medical Officer of Health
of the Winsford Urban District, Cheshire, pointed out how easy it would
be to apply Dr. Poore's principles to a garden city.


'A plot of 4 acres should be taken on the outskirts of a town and twenty
houses built upon it. Suppose the plot roughly square, and the road to
skirt one corner of it. Then this corner alone will possess that valuable
quality "frontage". Sacrifice this scrap of frontage by making a short
gravelled drive through it, to end blindly in a "turn-round" in the
middle of the plot. The houses should all face south--that is to say, all
their living rooms should face south. They must therefore be oblong, with
their long axes east and west (Fig. I). The larder, the lobby, lavatory,
staircase and landing will occupy the north side of each house. The earth
closet is best detached but approached under cover--a cross-ventilated
passage or short veranda, or, if upstairs, a covered bridge giving access
to it. The houses should be set upon the plot in a diamond-shaped
pattern, or in other words, a square with its corners to north, south,
east and west. Thus one house will occupy the northernmost point of the
plot, and from it, to the south-east and south-west, will run a row of
some five or six houses a side, arranged in echelon Just as platoons in
echelon do not block each other's line of fire so houses thus arranged
will not block each other's sunlight. A dozen more houses echeloned in a
V with its apex to the south will complete the diamond-shaped lay-out.
The whole plot would be treated as one garden, and one whole-time head
gardener, with the help he needed, would be responsible for its
cultivation. The daily removal of the closet earth and its use as
manure--its immediate committal to the surface soil and its light
covering therewith--would naturally be amongst his duties. A gardener
using manure of great value, not a scavenger removing refuse; a "garden
rate" paid by each householder, an investment productive of fresh
vegetables to be had at his door, and in one way or another repaying him
his outlay, not to speak of the amenity added to his surroundings,
instead of a "sanitary rate" paid to be rid of rubbish--such are the
bases of this scheme.'


Fig. 1 A model layout for 20 cottages


What is needed are a few working examples of such a housing scheme and a
published account of the results. These, if successful, would at once
influence all future building schemes in country districts and would
point the way to a considerable reduction in rents and rates. The
garden-city and water-borne sewage are a contradiction in terms.
Water-borne sewage has developed because of overcrowding and the absence
of cultivated land. Remove overcrowding and the case for this wasteful
system disappears. In the garden city there is no need to get rid of
wastes by the expensive methods of the town. The soil will do it far more
efficiently and at far less cost. At the same time the fertility of the
garden city areas will be raised and large crops of fresh vegetables and
fruit--one of the factors underlying health--will be automatically
provided.

Such a reform in housing schemes will not stop at the outer fringes of
our towns and cities. It will be certain to spread to the villages and to
the country-side, where a few examples of cottage gardens, rendered
fertile by the wastes of the inhabitants, are still to be found here and
there. More are needed. More will arise the moment it is realized that
the proper utilization of the wastes of the population depends on
composting processes and the correct use of humus. All the trouble, all
the expense, and all the difficulties in dealing with human wastes arise
from following the wrong principle--water--and setting in motion a vast
train of putrefactive processes. The principle that must be followed is
abundant aeration at the beginning: the conversion of wastes into humus
by the processes Nature employs in every wood and every forest.



BIBLIOGRAPHY

GREENWELL, SIR BERNARD. 'Soil Fertility: the Farm's Capital,' Journal
of the Farmers Club, 1939, p. 1.

HOWARD, SIR ALBERT. 'Preservation of Domestic Wastes for Use on the Land',
Journal of the Institution of Sanitary
Engineers, xliii, 1939, p. 173.

-------'Experiments with Pulverized Refuse as a Humus-Forming Agent',
Journal of the Institute of Public Cleansing,
xxix, 1939, p. 504.

JONES, B. B., and OWEN, F. Some Notes on the Scientific Aspects of
Controlled Tipping, City of Manchester, 1934.

PICTON, L. J. 'The Economic Disposal of Excreta: Garden Sanitation',
British Medical Journal, February 9th, 1924.

POORE, G. V. Essays on Rural Hygiene, London, 1894.

Public Cleansing Costing Returns for the year ended March 31st, 1938,
H. M. Stationery Office, 1939.





PART III  HEALTH, INDISPOSITION, AND DISEASE IN AGRICULTURE




CHAPTER IX



SOIL AERATION


The transformation of soil fertility into a crop is only possible by
means of oxidation processes. The various soil organisms--bacteria and
fungi in particular--as well as the active roots need a constant supply
of oxygen. As soon as this was recognized, aeration became an important
factor in the study of the soil. In this matter, however, practice has
long preceded theory: many devices such as sub-soil drainage,
sub-soiling, as well as mixed cropping--all of which assist the
ventilation of the soil--have been in use for a long time.

The full significance of soil aeration in agriculture has only been
recognized by investigators during the last quarter of a century. The
reason is interesting. Till recent years most of the agricultural
experiment stations were situated in humid regions where the rainfall is
well distributed. Rain is a saturated solution of oxygen and is very
effective in supplying this gas to the soil whenever percolation is
possible. Hence in such regions crops are not likely to suffer from poor
aeration to anything like the same extent as those grown in the arid
regions of North-West India where the soils are silt-like and most of the
moisture has to be supplied by irrigation water low in dissolved oxygen.
Such soils lose their porosity with the greatest ease when flooded; the
minute particles run together and form an impermeable surface crust. Only
when the humus content is kept high can adequate permeability be
maintained. Long before the advent of the modern canal, the cultivators
of India had acted on this principle. The organic matter content of the
areas commanded by wells has always been maintained at a high level.
Irrigation engineers and Agricultural Departments have been slow to
utilize this experience. Canal water has been provided, but no steps have
been taken simultaneously to increase the humus content of the soil.

It follows from the constant demands of the soil for fresh air that any
agency which interferes, even partially or temporarily, with aeration
must be of supreme importance in agriculture. A number of factors occur
which bring about every gradation between a restricted oxygen supply and
complete asphyxiation. The former result in infertility, the latter in
the death of the soil.


PLATE III. Rainfall, Tempeature, Humidity, and Drainage, Pusa, 1922


How does the plant respond to soil conditions in which oxygen becomes the
limiting factor? Generally speaking there is an immediate reaction on the
part of the root system. This is well seen in forest trees and in the
undergrowth met with in woodlands. The roots adjust themselves to the new
conditions; the trees establish themselves and at the same time improve
the aeration and also add to the fertility of the soil; incidentally all
other competitors are vanquished. Soil aeration cannot therefore be
studied as if it were an isolated factor in soil science. It must be
considered along with (1) the responses of the root system to deficient
air, (2) the relation between root activity and soil conditions
throughout the year, and (3) the competition between the roots of various
species. In this way the full significance of this factor in agriculture
and in the maintenance of soil fertility becomes apparent. This is the
theme of the present chapter. An attempt will be made to explain soil
aeration as it affects the plant in relation to the environment and to
show how the plant itself can be used as a research agent.


THE SOIL AERATION FACTOR IN RELATION TO GRASS AND TREES

Between the years 1914 and 1924 the factors involved in the competition
between grass and trees were investigated by me at Pusa. Three main
problems were kept in view, namely, (1) why grass can be so injurious to
fruit trees, (2) the nature of the weapons by which forest trees vanquish
grass, and (3) the reaction of the root system of trees to the aeration
of the soil. An account of this study was published in the PROCEEDINGS OF
THE ROYAL SOCIETY OF LONDON in 1925 (B, vol. xcvii, pp. 284-321). As the
results support the view that in the investigation of the soil aeration
factor the plant can always make an important contribution, a summary of
the main results and a number of the original illustrations have been
included in this chapter.

The climatic factors at Pusa are summed up in Plate III. It will be seen
that after the break of the south-west monsoon in June, the humidity
rises followed by a steady upward movement in the ground water-level till
October when it falls again. In 1922 the total rise of the sub-soil
water-level was 16.5 feet, a factor which is bound to interfere with the
oxygen supply, as the soil air which is rich in carbon dioxide is slowly
forced into the atmosphere by the ascending water-table.

The soil is a highly calcareous silt-like loam containing about 75 per
cent. of fine sand and about 2 per cent. of clay. About 98 per cent. will
pass through a sieve of 80 meshes to the linear inch. There is no line of
demarcation between soil and sub-soil: the subsoil resembles the soil and
consists of alternating layers of loam, clay, and fine sand down to the
sub-soil water, which normally occurs about 20 feet from the surface. The
percentage of calcium carbonate is often over 30, while the available
phosphate is in the neighbourhood of 0.001 per cent. In spite of this low
content of phosphate, the tract in which Pusa is situated is highly
fertile, maintaining a population of over 1,200 to the square mile and
exporting large quantities of seeds, tobacco, cattle, and surplus labour
without the aid of any phosphatic manures. The facts relating to
agricultural production in this tract flatly contradict one of the
theories of agricultural science, namely, the need for phosphatic
fertilizers in areas where soil analysis shows a marked deficiency in
this element. Two other factors, however, limit crop production--shortage
of humus and loss of permeability during the late rains due to a
colloidal condition of the soil; the pore spaces near the surface become
water-logged; percolation stops and the soil is almost asphyxiated, a
condition which is first indicated by the behaviour of the root system
and then by restricted growth.


FIG. 2. Plan of Experimental Fruit Area, Pusa.


For the investigation of the soil aeration factor in relation to grass
and trees at Pusa, eight species of fruit trees--three deciduous and five
evergreen--were planted out in three acres of uniform land, each species
being raised from a single parent. The plan (Fig. 2) gives further
details and makes the arrangement clear. Two years after planting, when
the trees were fully established and remarkably even, a strip including
nine trees of each of the eight rows was laid down to grass. The two end
plots, which were clean cultivated, served as controls. When the grass
was well established and its injurious effect on the young trees was
clearly marked, the three southern trees of the grass plot were provided
with aeration trenches, 18 inches wide and 24 inches deep filled with
broken bricks, these trenches being made midway between the lines of
trees. To ascertain the effect of grass on established trees in full
bearing, the southern strip of the northern control plot was grassed over
in 1921. The general results of the experiment, as seen in 1923, are
shown in Plate IV. The harmful effect of grass on fruit trees at Pusa is
even more intense than on clay soils like those of Woburn in Great
Britain. Several species were destroyed altogether within a few years.


PLATE IV. The harmful effects of grasss on fruit trees, Pusa, 1923


As great differences in root development were observed between the trees
under grass, under grass with aeration trenches, and under clean
cultivation, the first step in investigating the cause of the harmful
effect of grass appeared to be a systematic exploration of the root
system under clean cultivation so as to establish the general facts of
distribution, to ascertain the regions of root activity during the year
and to correlate this information with the growth of the above ground
portion of the trees. This was carried out in 1921 and the work was
repeated in 1922 and again in 1923. The method adopted was direct: to
expose the root system quickly and to use a fine waterjet for freeing the
active roots from the soil particles. By using a fresh tree for each
examination and by employing relays of labourers, it was possible to
expose any desired portion of the root system down to 20 feet in a few
hours and to make the observations before the roots could react to the
new conditons.


THE ROOT SYSTEM OF DECIDUOUS TREES

The root systems of three deciduous trees--the plum, the peach, and the
custard apple--were first studied. The results obtained in the three
species were very similar, so it is only necessary to describe in detail
one of them--the plum.

The local variety of plum sheds its leaves in November and flowers
profusely in February and March. The fruit ripens in early May, the
hottest period of the year. The new shoots are produced during the hot
weather and early rains.

The root system is extensive and appears at first to be entirely
superficial and to consist of many large freely branching roots running
more or less parallel to the surface in the upper 18 inches of soil.
Further exploration disclosed a second root system. From the under side
of the large surface roots, smaller members are given off which grow
vertically downwards to about 16 feet from the surface. These break up
into many branches in the deep layers of moist fine sand, just above the
water-table. The Indian variety of plum therefore has two root systems
(Plate V, Fig. I). The deep root system begins to develop soon after the
young trees are planted out. In August 1923 the root systems of young
custard apples, mangoes, guavas, limes, and loquats, planted in March
1922 were examined. The young vertical roots varied in length from 10
inches in the custard apple and lime to 1 foot in the mango, 1 foot 2.5
inches in the guava and 1 foot 8 inches in the loquat. Newly planted
trees form the superficial system first of all, followed rapidly by the
deep systems.


PLATE V. Plum (Prunus communis, Huds.)
Fig. 1. Superficial and deep roots (April 25, 1921)
Fig. 2. The repair of the deep root-system (August 6, 1923)
Fig. 3. Superficial rootlets growing towards the surface (August 12, 1922)
Figs. 4 and 5. New wood under cultivation and grass (January 25, 1923)
Figs. 6 and 7. New shoots and leavesunder clean cultivation
(April 5, 1923)
Figs. 8 and 9. The corresponsing growth under glass (April 5, 1923)


During the resting period (December to January) occasional absorbing
roots are formed in the superficial system. When flowering begins, the
formation of new rootless spreads from the surface to the deep soil
layers. As the surface soil dries in March, the active roots on the
superficial system turn brown and die and this portion passes into a
dormant condition. From the middle of March to the break of the rains in
June, root absorption is confined entirely to the deeper layers of soil.
Thus on April 14th, 1921, when the trees were ripening their fruit and
making new growth during a period of intense heat and dryness, most of
the water, nitrogen, and minerals necessary for growth were absorbed from
a layer of moist fine sand between 10 feet 6 inches and 15 feet below the
surface. This state of affairs continues till the break of the rains in
June when a sudden change takes place. The moistening of the surface soil
rapidly brings the superficial root system into intense activity. These
hitherto dormant roots literally break into new active rootlets in all
directions, the process beginning about thirty hours after the first fall
of rain. In the early monsoon therefore the trees use the whole of the
root system, both superficial and deep. A change takes place during late
July as the level of the ground water rises. In early August active roots
are practically confined to the upper 2 feet of soil. Absorption is now
restricted to the surface system. At this period the active roots react
to the poor soil aeration due to the rise in the ground water-level by
growing towards the atmosphere and even out of the soil into the air,
particularly under the shade of the trees and where the soil is covered
by a layer of dead leaves (Plate V, Fig. 3). This aerotropism continues
till early October, when the growth above ground stops and the trees
ripen their wood preparatory to leaf fall and the cold weather rest.
During October, as the level of the ground water falls and air is drawn
into the soil, there is some renewal of root activity near the surface
and down to 3 feet.

One interesting exception to this periodicity in the root activity of the
plum occurs. Falls of rain, nearly an inch in amount, sometimes occur
during the hot season. The effect on the superficial root system of the
plum of three of these storms was investigated. When the rainfall was
0.75 of an inch or more, the surface roots at once responded and produced
a multitude of new absorbing roots. As the soil dried these ceased to
function and died. In one case, where the rainfall was only 0.23 inches,
no effect was produced. Irrigation during the hot weather acts in a
similar manner to these sudden falls of rain. It maintains the surface
root system in action during this period and explains why irrigation
during the hot months is necessary on the alluvium if really good quality
fruit is to be obtained. It is true that without artificial watering the
trees ripen a crop at Pusa, but in size and quality the crop is greatly
inferior to that obtained with the help of irrigation. Either root system
will produce a plum. High quality is obtained only when the surface
system functions; poor quality always results when the deep system only
is in action.

In the detailed examination of the active surface roots of the plum and
of the seven other species in this experiment, fresh fungous mycelium was
often observed running from the soil towards the growing roots. In the
deeper soil layers this was never observed. In all probability this
mycelium is connected with the mycorrhizal association so common in fruit
trees. This matter was not carried further at the time. It is, however,
more than probable that all the eight species of fruit trees in the Pusa
Experiment are mycorrhiza-formers and that the fungus observed round the
active roots was concerned with this association. The mycorrhizal
relationship in the surface roots is probably involved in the production
of high quality fruit. Plants with two root systems such as these are
therefore admirably adapted for the future study of the relation between
humus in the soil, the mycorrhizal association, and the development of
quality. It would not be difficult to compare plants grown side by side
on the sub-soil (to remove the humus occurring in the surface soil), the
one manured with complete artificials, the other with freshly prepared
humus. In the former there would be little or no mycorrhizal invasion; in
the latter it would probably be considerable. If, as is most likely, the
mycorrhizal association enables the tree to absorb nutrients in the
organic form by the digestion of fungous mycelium, this would explain why
quality only results when the surface roots are in action.

Support for the view of plant nutrition suggested in the preceding
paragraph was supplied by the custard apple, the root development of
which is similar to that of the plum and peach. In the custard apple new
shoots are formed in the hot weather when the water, nitrogen, and
nutrients are obtained from the deep soil layers only. After the break in
the rains and the resumption of root activity on the surface, the leaves
increase in size (from 5.8 x 2.6 cm. to 10.5 x 4.5 cm.), develop a deeper
and healthier green, while the internodes lengthen. The custard apple
records the results of these various factors in the size and colour of
its leaves and in this way acts as its own soil analyst.

While this book was being printed specimens of the young active roots of
the custard apple, mango, and lime were collected in Mr. Hiralal's
orchard, Tukoganj, Indore, Central India, on November 11th, 1939, by Mr.
Y. D. Wad. They were examined by Dr. Ida Levisohn on December 19th, 1939,
who reported that all three species showed typical endotrophic
mycorrhizal infection indicated macroscopic ally by the absence of root
hairs, or great reduction in their number, and, in the mango
particularly, by beading. The active hyphae in all three cases were of
large diameter, with thin walls and granular contents, the digestion
stages occurring in the inner cortex with clumping of mycelium, remains
of hyphae and homogeneous granular masses. Absorption of the fungus
appeared to be taking place with great rapidity. In the custard apple the
same kind of mycelium was found outside the roots and connected with
them.


THE ROOT SYSTEM OF EVERGREENS

The most interesting root system of the five evergreens studied--mango,
guava, litchi, sour lime, and loquat--was the guava.


PLATE VI. Guava (Psidium Guyava, L)
Fig. 1. Superficial and deep roots (November 23, 1921)
Fig. 2. The influence of soil texture on the formation of the rootlets
(March 29, 1921)
Fig. 3. The root-system under grass (April 21, 1921)
Fig. 4. Superficial rootlets growing to the surface (August 28, 1921)
Fig. 5. Formation of new rootletsin fine sand following the fall of
the ground water (November 20, 1921)
Fig. 6. Reduction in the size of leaves after 20 months under grass
(right).


The guava drops its foliage in early March, simultaneously producing new
leaves. It proved an excellent plant for the study of the root system, as
the reddish roots are strongly developed and easy to follow in a grey
alluvial soil like that of Pusa. There is an abundant superficial system
giving off numerous branches which grow downwards to the level of
permanent water (Plate VI, Fig. 1). The whole of the root system,
superficial and deep, was found to be active at the beginning of the hot
weather (March 21st, 1921), the chief zone of activity occurring in a
moist layer of fine sand 10 feet 4 inches to 14 feet 7 inches from the
surface. As the hot weather became established, the absorbing roots of
the guava near the surface dried up and root activity was confined to the
deeper layers of soil. In 1922 the monsoon started on June 3rd. An
exposure of the surface roots was made on June 5th, forty-eight hours
after the rains started. From 1 foot 5 inches to 12 feet new roots were
found in large numbers, the longest measuring I cm. As the soil became
moistened by the early rains, the dormant zone produced new roots from
above downwards till the whole root system became active. After July a
change takes place as the ground water rises, the deep roots becoming
dormant as immersion proceeds. On August 25th, 1922, root activity was
mainly confined to the surface system in the upper 29 inches of soil, the
last active root occurring at 40 inches. In the late rains the active
roots escape asphyxiation by becoming strongly aerotropic (Plate VI, Fig.
4). An interesting change takes place after the level of the sub-soil
water falls in October and the aeration of the lower soil layers is
renewed. The deep root system again becomes active in November, the
degree of activity depending on the monsoon rainfall (Plate VI, Fig. 5).
In 1921, a year of short rainfall when the rise of the ground water was
very small, the deep roots came into activity in November down to 15 feet
3 inches. The next year--November 1922--when the monsoon and the rise of
the ground water were both normal, root activity did not extend below 5
feet 7 inches.

Although the guava is able to make new growth during the hot season by
means of its deep root system it is a decided advantage if the surface
roots are maintained in action by means of irrigation. Surface watering
in the hot weather of 1921 increased the size of the leaves from 9.1 x
4.0 cm. to 11.6 x 5.0 cm. and greatly improved their colour.

The root system and the development of active roots in the mango, litchi,
lime, and loquat follow generally what has been described in the guava.
All these species give off vertical roots from the surface system, but in
the case of the litchi and the lime these did not penetrate to the deeper
layers. The roots of all four species exhibit marked aerotropism in the
late rains. The vertical roots of the lime were always unable to
penetrate the deeper layers of clay.


THE HARMFUL EFFECT OF GRASS

The harmful effect of grass on fruit trees varies with the species and
with the period in the life of the tree when the grass is planted. Young
trees are more adversely affected than fully developed individuals, which
contain large quantities of reserves in the wood. Deciduous species
suffer more than evergreens. These facts suggest that the harmful effect
of grass is a consequence of starvation.

The effect of grass on young trees was first studied. The custard apple
was the most sensitive. The trees were killed in 1916 within the first
two years after the grass was planted. Next in order of susceptibility
were the loquat (all died before the end of 1919), the plum, the lime,
and the peach. The litchi and the mango just managed to maintain
themselves. The guava was by far the least affected, the trees under
grass being almost half the height of those under clean cultivation.

Grass not only reduces the amount of new growth but affects the leaves,
branches, old wood, and fruit as well as the root system. The results
relating to the above ground portion of the trees closely follow those
described by the Woburn investigators. Compared with the foliage produced
under clean cultivation, the leaves from the trees under grass appear
later, are smaller and yellower and fall prematurely. The internodes are
short. The bark of the twigs is light coloured, dull, and unhealthy and
quite different from that of healthy trees. The bark of the old wood has
a similar appearance and attracts lichens and algae to a much greater
extent than that of the cultivated trees. The trees under grass flower
late and sparingly. The fruit is small, tough, very highly coloured, and
ripens earlier than the normal.

The effect of grass on the root system is equally striking. Except in the
guava, the effect of grass on the superficial system is to restrict the
amount of root development, to force the roots below the grass, and to
reduce the number of active roots during the monsoon. The guava is an
exception. The surface system is well developed, the roots are not driven
downwards by the grass while active rootless are readily formed in the
upper 4 inches of soil soon after the rains begin, very much as in the
cultivated trees. In August 1922, when the ground water had risen to its
highest point, the absorbing roots of the guava were found in the surface
film of soil, and also above the surface among the stems of the grass.
The grass carpet therefore acts as an asphyxiating agency in all these
species, the guava excepted.

The grass covering has no appreciable effect either on the development or
on the activity of the deep roots. This portion of the root system was
explored during the hot weather of 1921 in the case of the guava (Plate
VI, Fig. 3), mango, and litchi and results were obtained very similar to
those in the corresponding cultivated trees.

Grass not only affects the roots underneath but also the development of
those of the neighbouring trees under cultivation. Such roots either turn
away from the grass, as in the custard apple, or else turn sharply
downwards before they reach it.

A number of conclusions can be drawn from these root exposures. The
custard apple, loquat, peach, and lime are unable to maintain their
surface root systems under grass, but behave normally as regards the deep
root system. Only the guava is able to get its roots above those of the
grass during the rains.

The study of the harmful effect of grass on established trees also
yielded interesting results. In this case the trees carried ample
reserves in the wood and, as might be expected, the damage was less
spectacular than in the case of young trees with little or no reserves.
The order of susceptibility to grass, however, was very much the same in
the two cases. When the fully-grown trees were first put under grass in
August 1921, the grass at first grew poorly in tufts with bare ground
between. Even this imperfect covering soon affected the custard apples,
loquats, peaches, and litchis. By the rains of 1922 the grass became
continuous; the effect on the trees was then much more marked.

In the plum interesting changes occurred. In July 1922, less than a year
after planting the grass, the new shoots showed arrested growth and the
foliage was attacked by leaf-destroying insects, which, however, ignored
the leaves of the neighbouring cultivated plot. If the insects were the
real cause of the trouble, it is difficult to see why the infection did
not spread beyond the trees under grass. In January 1923 the average
length of the new wood in these trees was 1 foot 5 inches compared with 3
feet 7 inches in the controls. The twigs were dull and purplish, the
internodes were short (Plate V, Fig. 5). In February 1923 flowering was
restricted and in April only tufts of leaves were formed at the ends of
the branches instead of new shoots (Plate V, Fig. 8). Early in 1924, when
I left Pusa and had to discontinue the work, a great deal of die-back was
taking place.

Very similar results were obtained in all the species except the mango,
which resisted grass better than any of the others. No definite effect
was observed in this species till June 1923, when the foliage became
distinctly lighter than that of the cultivated trees. The general results
brought about by grass in all these cases suggested that the trees were
slowly dying from starvation.

A year after the grass was planted and the grass effect was becoming
marked, the root system of these established trees was examined. In
August 1922 the plums, peaches, custard apples, mangoes, litchis, and
loquats under grass were found to have produced very few active rootless
in the upper foot of soil compared with the controls. In the case of the
custard apples and the loquats, which suffered most from grass, there was
a marked tendency for the new roots to grow downwards and away from the
grass. No differences were observed in the dormancy or activity of the
deep root system as compared with the controls. The deep roots behaved
exactly like those under clean cultivation.


FIG. 4. The effect of burrowing rats on the growth of the plum under
grass (June 21st, 1923)


During these examinations two instances of the striking effect of
increased aeration on root development were observed. In July 1923
burrowing rats took up their quarters under one of the limes and one of
the loquats, in each case on the southern side. Shortly afterwards the
leaves just above the rat holes became very much darker in colour than
the rest. Examination of the soil immediately round the burrows showed a
copious development of new active rootless, far greater even than in the
surface soil of the cultivated plot. The extra aeration had a wonderfully
stimulating effect on the development of active roots, even under grass.
The appearance of the leaves suggested an application of nitrogenous
manure. Similar observations were made in the case of the plum (Fig. 4).
Here the burrows caused a dying tree to produce new growth.


THE EFFECT OF AERATION TRENCHES ON YOUNG TREES UNDER GRASS

The effect of aeration trenches in modifying the influence of grass
suggests that one of the factors at work is soil asphyxiation. In the
case of the custard apple and the lime the aeration trenches had no
effect; all the trees died. The death of the plums was delayed by the
aeration trenches. The loquats, litchis, and mangoes benefited
considerably. In the guavas the trees provided with aeration trenches
were indistinguishable from those under grass. The general results are
shown in Table 8, in which the measurements of a hundred fully-developed
leaves, made in March 1921, are recorded.


TABLE 8

The reduction in leaf size under grass

                    Grass     Grass with aeration     Cultivated
                    (cm.)       trenches (cm.)           (cm.)
Plum              3.2 x 1.1      4.6 x 1.7             7.1 x 2.9
Peach             7.1 x 1.8      8.2 x 2.3            11.4 x 3.1
Guava             8.1.x 3.2     10.6 x 4.4            11.3 x 4.4
Mango            11.2 x 2.9     13.7 x 3.8            20.9 x 5.5
Litchi            8.9 x 2.4     11.5 x 3.4            12.2 x 3.5
Lime              3.8 x 1.6      5.2 x 2.1             6.4 x 3.4
Loquat           Trees dead     16.4 x 4.6            22.1 x 5.9


At the end of 1920 the roots were exposed to a depth of 2 feet in order
to ascertain the effect of the extra aeration on the development of the
superficial system. The results were interesting. In all cases the
superficial roots were much larger and better developed than those under
grass, except in the guava where no differences in size could be detected.
The roots were attracted by the trenches, often branching considerably
in the soil at the side of the trenches themselves. The aeration
trenches are made use of only during the monsoon phase. After the
break of the rains, new active roots are always found in or near the
trenches first, after which a certain amount of development takes place
under the grass.

The deep root system of the trees provided with aeration trenches behaved
exactly like the controls.


THE RESULTS OBTAINED

The general results obtained with clean cultivation, grass, and grass
with aeration trenches are shown in Plate IV, in which representative
trees from the various plots have been drawn to scale. The drawings
give a good idea of the main results of the experiment, namely:
(1) the extremely deleterious effect of grass on young trees;
(2) the less harmful effect of the same treatment on mature trees;
(3) the partial recovery which sometimes takes place from the aeration
trenches; and (4) the exceptional nature of the results with the guava,
where the trees are able to grow under grass, but with reduced vigour,
and where the aeration trenches have had little or no effect.

As would be expected from these results even a temporary removal of the
grass cover has a profound effect. Whenever the roots of a tree under
grass are exposed (for which purpose the grass has to be removed for
a few days) there is an immediate increase in growth, accompanied by
the formation of larger and darker-coloured leaves. The effect is
clearly visible in the foliage above the excavation for as long as
two years, but the rest of the tree is not affected.


THE CAUSE OF THE HARMFUL EFFECT OF GRASS

The examination of the root system of these eight species suggested that
the first step in working out the cause of the harmful effect of grass
would be to make a periodical examination of the soil gases.
Determinations of the amount of CO2 in the soil-air at a depth of 9 to 12
inches were carried out during 1919 under grass, under grass with
aeration trenches, and under cultivated soil. About 10 litres of air
were drawn out of the soil at each determination and passed through
standard baryta which was afterwards titrated in the ordinary way.
The 1919 results are given in Table 9 and are set out graphically
in Fig. 5.


TABLE 9

Percentage by volume of carbon dioxide in the soil-gas
under grass and clean cultivation, Pusa, 1919

Date and month when    Plot no. 1   Plot no 2       Plot no 2     Rainfall
soil-gas was aspirated  grassed   grassed, but       surface     in inches
and analysed                    partially aerated  cultivated      since
                                   by trenches                    1/1/1919

January 13, 14 and 17    0.444       0.312           0.269           Nil
February 20 and 21       0.472       0.320           0.253          1.30
March 21 and 22          0.427       0.223           0.197          1.33
April 23 and 24          0.454       0.262           0.203          2.69
May 16 and 17            0.271       0.257           0.133          3.26
June 17 and 18           0.341       0.274           0.249          4.53
July 17 and 18           1.540       1.090           0.304         14.61
August 25 and 26         1.590       0.836           0.401         23.29
September 19 and 20      1.908       0.931           0.450         30.67
October 21 and 22        1.297       0.602           0.365         32.90
November 14 and 15       0.853       0.456           0.261         32.90
December 22 and 23       0.398       0.327           0.219         32.92


The results of 1920 and 1921 confirm these figures in all respects.
Table 9 shows that during the monsoon the volume of carbon dioxide in
the pore spaces under grass is increased about fivefold in comparison
with the soil-air of cultivated land. As this gas is far more soluble
in water than oxygen, the amounts of carbon dioxide actually dissolved
in the water-films in which the root-hairs work would be much higher
than the figures in the table suggest.

The production of large amounts of carbon dioxide in the soil-air during
the rains would also affect the formation of humus, nitrification, and
the mycorrhizal relationship, all of which depend on adequate aeration.
Considerable progress was made in the investigation of the supply of
combined nitrogen. At all periods of the year, except at the break of
the rains, the amount of nitric nitrogen in the upper 18 inches of soil
under grass varied from 10 to 20 per cent. of that met with in the
cultivated plots. When the shortage of nitrogen in the case of the
guava was made up by means of sulphate of ammonia during the rains
of 1923, the trees under grass at once responded and produced fruit
and foliage hardly distinguishable in size from the controls.


FIG. 5. Carbon dioxide in soil atmosphere, Pusa, 1919.


In the case of the litchi and loquat, the roots of which are unable
to aerate themselves in the rains by forcing their way through the grass
to the surface, heavy applications of combined nitrogen improved the
growth, but a distinctly harmful effect remained--the manured trees
as regards size and colour of the leaves, time of flowering, and
production of new shoots occupying an intermediate position between
the unmanured trees under grass and those under clean cultivation.
These results are very similar to those obtained with apples at Cornell.
At both places grass led to the disappearance of nitrates in the soil
and restricted root development. The effect was only partially removed
by the addition of nitrate of soda.; In the guava, however, combined
nitrogen removes the harmful effect because the roots of this tree are
able to obtain all the oxygen they need. The guava, therefore, suffers
from only one of the factors resulting from a grass carpet--lack of
nitrate. The litchi and the loquat suffer from another factor as
well--lack of oxygen.


FOREST TREES AND GRASS

Although the grass carpet acts as an asphyxiating agent to the roots
of all the fruit-trees investigated except the guava, the ordinary
Indian forest trees thrive under grass. Between the years 1921 and 1923
the relation between the grass carpet and the roots of the following
fifteen forest trees was investigated (Table 10). All thrive remarkably
well under grass and show none of the harmful effects exhibited by
fruit-trees.

Most of the forest trees in the plains of India flower and come into
new leaf in the hot season and then proceed to form new shoots. After
the early rains a distinct change is visible in the size, colour, and
appearance of the foliage. The leaves become darker and more glossy;
the story told by the young shoots of the custard apple is repeated.


TABLE 10

Forest trees under grass in the Botanical Area, Pusa

Species                    Time of flowering       Time of leaf-fall
Polyalthia longifolia
Benth. & Hook, f.             February-April              April
Melia Azadirachta L.          March-May                   March
Ficus bengalensis L.          April-May                   March
Ficus religosa L.             April-May                   December
Ficus infectoria Roxb.        February-May                December-January
Millingtonia hortensis
Linn., f.                     November-December           March
Butea frondosa Roxb.          March                       February
Phyllanthus Emblica L.        March-May                   February
Tamarindus indica L.          April-June                  March-April
Tectonia grandis Linn., f.    July-August                 February-March
Thespesia populnea Corr.      Throughout the year but
                              chiefly in the cold season  April
Pterospermum acerifolium
Willd.                        March-June                  January-Feburary
Wrightia tomentosa Roem.
& Schult.                     April-May                   January-February
Lagerstroemia Flos-Regina
Retz                          May                         December-January
Dalbergia Sissoo Roxb.        March                       December-January


Examination of the superficial root systems of the fifteen species
during the rains of 1922 and 1923 yielded remarkably uniform results.
All the trees produced abundant, normally developed active rootless in
the upper 2 or 3 inches of soil and also on the surface; they therefore
compete successfully with grass both for oxygen and nitrates. The large
superficial roots were also well developed and compared favourably with
the corresponding root system of fruit-trees under clean cultivation.
The grass carpet had apparently no harmful effect on the root system
near the surface.

Between the hot weather of 1921 and the early months of 1924 the
complete root systems of these fifteen species were investigated. In all
cases the large surface roots gave off thin branches which grew
vertically downwards to the cold-season level of the ground water. Root
activity in all cases was practically confined in the hot season to the
deep moist layers of sand between 10 and 20 feet below the surface, the
roots always making the fullest use of the tunnels of Termites and other
burrowing insects for passing easily through clay layers from one zone
of sandy soil to the next below. Cavities in the soil were always fully
used for root development. Soon after the rains the dormant surface
roots burst into activity. As the ground water rose the deep root system
became dormant; in August the active surface roots always showed marked
aerotropism. The formation of nitrates which takes place about the time
the cold-season crops are sown was followed by a definite burst of
renewed root activity in the surface soil, followed by the production of
new shoots and leaves. As the ground water falls in the autumn and the
soil draws in oxygen, the formation of active roots follows the
descending water-table exactly as has been described in the case of the
guava.

The facts of root distribution and periodicity in root activity in
forest trees explain why these trees do so well under grass and are able
to vanquish it if allowed free competition. The chief weapons which
enable forest trees to oust grasses and herbs from the habitat are the
following:

1. The deep root system admits of growth during the dry season when the
grass is dormant, thereby enabling the trees to utilize moisture and
food materials in the soil down to at least 20 feet. This markedly
extends the period of assimilation.

2. The habit of trees is a great advantage in the struggle for light.

3. The active roots of the surface system are resistant to poor soil
aeration, and are able to reach the surface and compete successfully
with the grass for oxygen and for minerals.

The character which distinguishes forest trees from fruit-trees is the
power possessed by the surface roots of the former to avoid the
consequences of poor soil aeration by forcing their way through a grass
carpet in active growth to the air and to obtain oxygen as well as a
share of the nitrates in the surface soil. The surface roots of most
fruit-trees are very susceptible to carbon dioxide and try to avoid it
by growing downwards. The trees are therefore deprived of oxygen and of
combined nitrogen during the rains, and slowly starve. The guava is an
exception among fruit-trees. Here the active roots reach the surface in
the rains and the trees are able to maintain themselves. This explains
why the pastures of Grenada and St. Vincent in the West Indies are so
rapidly invaded and destroyed by the wild guava. The hedgerows and
pastures of Great Britain if left to themselves behave in a similar way.
The hedgerows soon begin to invade the fields. Young trees make their
appearance; grass areas become woodland. The transformation, however, is
much slower in Great Britain than in the tropics.

These studies on the root development of tropical forest trees throw a
good deal of light on the soil aeration factor and the part the plant
can play in such investigations. The movement of the ground water
affects soil aeration directly. The two periods--the beginning and end
of the rainy season--when the surface soil contains abundant air and
ample moisture and when the temperature is favourable for nitrification,
correspond exactly with times when nitrates accumulate and when growth
is at its maximum. When soil aeration is interfered with during the
rains by two factors, (1) the rise of the ground water, and (2) the
formation of colloids in the surface soil, the plant roots respond by
growing to the surface. Root development, therefore, is an important
instrument in such an investigation when examined throughout the year.

The root development of trees influences the maintenance of soil
fertility in the plains of India and indeed in many other regions. The
dead roots provide the deeper layers of soil with organic matter and an
almost perfect drainage and aerating system. The living roots comb the
upper 20 feet of soil for such minerals as phosphates and potash which
are used in the green leaves. These leaves in due course are converted
into humus and help to enrich the surface soil. This explains why the
soils of North Bihar, although very low in total and available
phosphates, are so exceedingly fertile and yield heavy crops without any
addition of mineral manures. The figures given by the analysis of the
surface soil must be repeated in the lower layers and should be
interpreted not in terms of the upper 9 inches but of the upper 20 feet.

The tree is the most efficient agent available for making use of the
minerals in the soil. It can grow almost anywhere, it will vanquish most
of the other forms of vegetation, and it will leave the soil in a highly
fertile condition. It follows therefore that the trees and shrubs of the
hedgerows, parks, and woodlands of countries like Great Britain must
continue to be used for the maintenance of soil fertility. In Saxon
times most of our best land was under forest. The fertility stored in
the soil made the gradual clearing of this woodland worth while. In the
future, when agriculture comes into its own and when it is no longer
regarded solely as an industry, it may be desirable to embark on long
term rotations in which woods and park-land are turned into arable, and
worn-out arable back into woodland or into mixed grass and trees. In
this way the root system of the tree can be used to restore soil
fertility.


THE AERATION OF THE SUB-SOIL

One of the universal methods of improving aeration is subsoiling. The
methods adopted vary greatly according to the factor which has
interfered with aeration and the means available for improving the
air-supply.

In temperate regions the chief factor which cuts off the sub-soil from
the atmosphere is shortage of humus aggravated by impermeable pans
(produced by the plough and by the soil particles themselves) or a
permanent grass carpet accompanied by the constant treading of animals.
The result in all cases is the same--the supply of air to the sub-soil
is reduced.

In loamy soils plough-pans develop very rapidly if the content of
organic matter falls off and the earthworm population declines. A
well-defined zone of close and sticky soil is formed just under the
plough sole which holds up water, thereby partly asphyxiating the
sub-soil below and water-logging the soil above.

In sandy soils as well as in silts, pans are formed with the greatest
ease from the running together of the particles, particularly when
artificials take the place of farm-yard manure and the temporary ley is
not properly utilized. One of the most interesting cases of pan
formation that I have observed in Great Britain was on the permanent
manurial plots of the Woburn Experiment Station, where an attempt to
grow cereals year after year on the greensand by means of artificial
manures has been followed by complete failure of the crop. The soil has
gone on permanent strike. The destruction of the earthworm population by
the regular application of chemicals had deprived the land of its
natural aerating agencies. Failure to renew the organic matter by a
suitable rotation had resulted in a soil devoid of even a trace of
tilth. About 9 inches below the surface, a definite pan (made up of sand
particles loosely cemented together) occurred, which had so altered the
aeration of the sub-soil that the whole of these experimental plots were
covered with a dense growth of mares' tail (Equisetum arvense L.), a
perennial weed which always indicates a badly aerated sub-soil. Nature
as usual had summed up the position in her own inimitable fashion. There
was no need of tabulated yields, analyses, curves, and statistics to
explain the consequences of improper methods of agriculture.

The conventional method of dealing with arable pans in this country is
by means of some sub-soiling implement which breaks them up and restores
aeration. This should be accompanied whenever possible by heavy
dressings of farm-yard manure, so that the tilth can be improved and the
earthworm population restored. Some deep-rooted crop like lucerne, or
even a temporary fey, should be called in to complete the cure.
Sub-soiling heavy land under grass is proving even more advantageous
than on arable areas. This leads, as we have seen, to humus formation
under the turf and to an increase in the stock-carrying capacity of the
land.

In the East the ventilation of the sub-soil is perhaps even more
important than in the West. In India, for example, one of the common
consequences of the monsoon rainfall and of flooding the surface with
irrigation water is pan formation on a colossal scale due to the
formation of soil colloids--the whole of the surface soil tends to
become a pan. This has to be broken up. The cultivators of the Orient
set about this task in a very interesting way. Whenever they can use the
roots of a leguminous crop as a sub-soiler they invariably employ this
machine. It has the merit of costing nothing, of yielding essential food
and fodder, and of suiting the small field. In the Indo-Gangetic plain
the universal sub-soiler is the pigeon pea, the roots of which not only
break up soil pans with ease but also add organic matter at the same
time. On the Western frontier the sub-soiling of the dense loess soils
is always done by the roots of a lucerne crop. On the black cotton soils
of Peninsular India where the monsoon rainfall converts the whole of the
surface soil into a vast colloidal pan, the agricultural situation is
saved by the succeeding hot season which dries out this pan and reduces
its volume to such an extent that a multitude of deep fissures occur
right down to the sub-soil. The black soils of India plough and sub-soil
themselves. The moist winds, which precede the south-west monsoon in May
and early June, replace some of the lost moisture; the heavy clods break
down and when the early rains arrive a magnificent tilth can be prepared
for the cotton crop. The sub-soiling in this case is done by Nature; the
cultivators merely give a subsequent cultivation and then sow the crop.



BIBLIOGRAPHY

CLEMENTS, F. E. Aeration and Air Content: the Role of Oxygen in Root
Activity, Publication No. 315, Carnegie Institution of Washington, 1921.

HOWARD, A. Crop Production in India: A Critical Servey of its Problems,
Oxford University Press, 1924.

-------'The Effect of Grass on Trees', Proc. Royal Soc., Series B, xcvii,
1925, p. 284.

LYON, T. L., HEINICKE, A. J., and WILSON, D. D. The Relation of Soil
Moisture and Nitrates to the Effects of Sod on Apple Trees, Memoir 63,
Cornell Agricultural Expt. Station, 1923.

THE DUKE OF BEDFORD, and PICKERING, S. U. Science and Fruit-Growing,
London, 1919.

WEAVER, J. E., JEAN, F. C, and CRIST, J. W. Development and
Activities of Crop Plants, Publication No. 316, Carnegie Institution
of Washington, 1922.




CHAPTER X



SOME DISEASES OF THE SOIL


SOIL EROSION

Perhaps the most widespread and the most important disease of the soil
at the present time is soil erosion, a phase of infertility to which
great attention is now being paid.

Soil erosion in the very mild form of denudation has been in operation
since the beginning of time. It is one of the normal operations of
Nature going on everywhere. The minute soil particles which result from
the decay of rocks find their way sooner or later to the ocean, but many
may linger on the way, often for centuries, in the form of one of the
constituents of fertile fields. This phenomenon can be observed in any
river valley. The fringes of the catchment area are frequently
uncultivated hills through the thin soils of which the underlying rocks
protrude. These are constantly weathered and in the process yield a
continuous supply of minute fragments in all stages of decomposition.

The slow rotting of exposed rock surfaces is only one of the forms of
decay. The covering of soil is no protection to the underlying strata
but rather the reverse, because the soil water, containing carbon
dioxide in solution is constantly disintegrating the parent rock, first
producing sub-soil and then actual soil. At the same time the remains of
plants and animals are converted into humus. The fine soil particles of
mineral origin, often mixed with fragments of humus, are then gradually
removed by rain, wind, snow, or ice to lower regions. Ultimately the
rich valley lands are reached where the accumulations may be many feet
in thickness. One of the main duties of the streams and rivers, which
drain the valley, is to transport these soil particles into the sea
where fresh land can be laid down. The process looked at as a whole is
nothing more than Nature's method of the rotation, not of the crop, but
of the soil itself. When the time comes for the new land to be enclosed
and brought into cultivation agriculture is born again. Such operations
are well seen in England in Holbeach marsh and similar areas round the
Wash. From the time of the Romans to the present day, new areas of
fertile soil, which now fetch 100 pounds an acre or even more, have been
re-created from the uplands by the Welland, the Nen, and the Ouse. All
this fertile land, perhaps the most valuable in England, is the result
of two of the most widespread processes in Nature--weathering and
denudation.

It is when the tempo of denudation is vastly accelerated by human
agencies that a perfectly harmless natural process becomes transformed
into a definite disease of the soil. The condition known as soil
erosion--a man-made disease--is then established. It is, however, always
preceded by infertility: the inefficient, overworked, dying soil is at
once removed by the operations of Nature and hustled towards the ocean,
so that new land can be created and the rugged individualists--the
bandits of agriculture--whose cursed thirst for profit is at the root of
the mischief can be given a second chance. Nature is anxious to make a
new and better start and naturally has no patience with the inefficient.
Perhaps when the time comes for a new essay in farming, mankind will
have learnt a great lesson--how to subordinate the profit motive to the
sacred duty of handing over unimpaired to the next generation the
heritage of a fertile soil. Soil erosion is nothing less than the
outward and visible sign of the complete failure of a policy. The causes
of this failure are to be found in ourselves.

The damage already done by soil erosion all over the world looked at in
the mass is very great and is rapidly increasing. The regional
contributions to this destruction, however, vary widely. In some areas
like north-western Europe, where most of the agricultural land is under
a permanent or temporary cover crop (in the shape of grass or leys), and
there is still a large area of woodland and forest, soil erosion is a
minor factor in agriculture. In other regions like parts of North
America, Africa, Australia, and the countries bordering the
Mediterranean, where extensive deforestation has been practiced and
where almost uninterrupted cultivation has been the rule, large tracts
of land once fertile have been almost completely destroyed.

The United States of America is perhaps the only country where anything
in the nature of an accurate estimate of the damage done by erosion has
been made. Theodore Roosevelt first warned the country as to its
national importance. Then came the Great War with its high prices, which
encouraged the wasteful exploitation of soil fertility on an
unprecedented scale. A period of financial depression, a series of
droughts and dust-storms, emphasized the urgency of the salvage of
agriculture. During Franklin Roosevelt's Presidency, soil conservation
has become a political and social problem of the first importance. In
1937 the condition and needs of the agricultural land of the U.S.A. were
appraised. No less than 253,000,000 acres, or 61 per cent. of the total
area under crops, had either been completely or partly destroyed or had
lost most of its fertility. Only 161,000,000 acres, or 39 per cent. of
the cultivated area, could be safely farmed by present methods. In less
than a century the United States has therefore lost nearly three-fifths
of its agricultural capital. If the whole of the potential resources of
the country could be utilized and the best possible practices introduced
everywhere, about 447,466,000 acres could be brought into use--an area
somewhat greater than the present crop land area of 415,334,931 acres.
The position therefore is not hopeless. It will, however, be very
difficult, very expensive, and very time-consuming to restore the vast
areas of eroded land even if money is no object and large amounts of
manure are used and green-manure crops are ploughed under.

The root of this soil erosion trouble in the United States is misuse of
the land. The causes of this misuse include lack of individual knowledge
of soil fertility on the part of the pioneers and their descendants; the
traditional attitude which regarded the land as a source of profit;
defects in farming systems, in tenancy, and finance--most mortgages
contain no provisions for the maintenance of fertility; instability of
agricultural production (as carried out by millions of individuals),
prices and income in contrast to industrial production carried on by a
few large corporations. The need for maintaining a correct relation
between industrial and agricultural production so that both can develop
in full swing on the basis of abundance has only recently been
understood. The country was so vast, its agricultural resources were so
immense, that the profit seekers could operate undisturbed until soil
fertility--the country's capital--began to vanish at an alarming rate.
The present position, although disquieting, is not impossible. The
resources of the Government are being called up to put the land in
order. The magnitude of the effort, the mobilization of all available
knowledge, the practical steps that are being taken to save what is left
of the soil of the country and to help Nature to repair the damage
already done are graphically set out in Soils and Men, the Year Book of
the United States Department of Agriculture of 1938. This is perhaps the
best local account of soil erosion which has yet appeared.

The rapid agricultural development of Africa was soon followed by soil
erosion. In South Africa, a pastoral country, some of the best grazing
areas are already semi-desert. The Orange Free State in 1879 was covered
with rich grass, interspersed with reedy pools, where now only useless
gullies are found. Towards the end of the nineteenth century it began to
be realized all over South Africa that serious over-stocking was taking
place. In 1918 the Drought Investigation Commission reported that soil
erosion was extending rapidly over many parts of the Union, and that the
eroded material was silting up reservoirs and rivers and causing a
marked decrease in the underground water-supplies. The cause of erosion
was considered to be the reduction of vegetal cover brought about by
incorrect veld management--the concentration of stock in kraals,
over-stocking, and indiscriminate burning to obtain fresh autumn or
winter grazing. In Basutoland, a normally well-watered country, soil
erosion is now the most immediately pressing administrative problem. The
pressure of population has brought large areas under the plough and has
intensified over-stocking on the remaining pasture. In Kenya the soil
erosion problem has become serious during the last three years, both in
the native reserves and in the European areas. In the former, wealth
depends on the possession of large flocks and herds; barter is carried
on in terms of live stock; the bride price is almost universally paid in
animals; numbers rather than quality are the rule. The natural
consequence is over-stocking, over-grazing, and the destruction of the
natural covering of the soil. Soil erosion is the inevitable result. In
the European areas erosion is caused by long and continuous overcropping
without the adoption of measures to prevent the loss of soil and to
maintain the humus content. Locusts have of late been responsible for
greatly accelerated erosion; examples are to be seen where the combined
effect of locusts and goats has resulted in the loss of a foot of
surface soil in a single rainy season.

The countries bordering the Mediterranean provide striking examples of
soil erosion, accompanied by the formation of deserts which are
considered to be due to one main cause--the slow and continuous
deforestation of the last 3,000 years. Originally well wooded, no
forests are to be found in the Mediterranean region proper. Most of the
original soil has been washed away by the sudden winter torrents. In
North Africa the fertile cornfields, which existed in Roman times, are
now desert. Ferrari in his book on woods and pastures refers to the
changes in the soil and climate of Persia after its numerous and
majestic parks were destroyed; the soil was transformed into sand; the
climate became arid and suffocating; springs first decreased and then
disappeared. Similar changes took place in Egypt when the forests were
devastated; a decrease in rainfall and in soil fertility was accompanied
by loss of uniformity in the climate. Palestine was once covered with
valuable forests and fertile pastures and possessed a cool and moderate
climate; to-day its mountains are denuded, its rivers are almost dry,
and crop production is reduced to a minimum.

The above examples indicate the wide extent of soil erosion, the very
serious damage that is being done, and the fundamental cause of the
trouble--misuse of the land. In dealing with the remedies which have
been suggested and which are now being tried out, it is essential to
envisage the real nature of the problem. It is nothing less than the
repair of Nature's drainage system--the river--and of Nature's method of
providing the country-side with a regular water-supply. The catchment
area of the river is the natural unit in erosion control. In devising
this control we must restore the efficiency of the catchment area as a
drain and also as a natural storage of water. Once this is accomplished
we shall hear very little about soil erosion.

Japan provides perhaps the best example of the control of soil erosion
in a country with torrential rains, highly erodible soils, and a
topography which renders the retention of the soil on steep slopes very
difficult. Here erosion has been effectively held in check, by methods
adopted regardless of cost, for the reason that the alternative to their
execution would be national disaster. The great danger from soil erosion
in Japan is the deposition of soil debris from the steep mountain slopes
on the rice-fields below. The texture of the rice soils must be
maintained so that the fields will hold water and allow of the minimum
of through drainage. If such areas became covered with a deep layer of
permeable soil, brought down by erosion from the hill-sides, they would
no longer hold water, and rice cultivation--the mainstay of Japan's
food-supply--would be out of the question. For this reason the country
has spent as much as ten times the capital value of eroding land on soil
conservation work, mainly as an insurance for saving the valuable rice
lands below. Thus in 1925 the Tokyo Forestry Board spent 453 yen
(45 pounds) per acre in anti-erosion measures on a forest area, valued at
40 yen per acre, in order to save rice-fields lower down valued at 240
to 300 yen per acre.

The dangers from erosion have been recognized in Japan for centuries and
an exemplary technique has been developed for preventing them. It is now
a definite part of national policy to maintain the upper regions of each
catchment area under forest, as the most economical and effective method
of controlling flood waters and insuring the production of rice in the
valleys. For many years erosion control measures have formed an
important item in the national budget.

According to Lowdermilk, erosion control in Japan is like a game of
chess. The forest engineer, after studying his eroding valley, makes his
first move, locating and building one or more check dams. He waits to
see what Nature's response is. This determines the forest engineer's
next move, which may be another dam or two, an increase in the former
dam, or the construction of side retaining walls. After another pause
for observation, the next move is made and so on until erosion is
checkmated. The operation of natural forces, such as sedimentation and
re-vegetation, are guided and used to the best advantage to keep down
costs and to obtain practical results. No more is attempted than Nature
has already done in the region. By 1919 nearly 2,000,000 hectares of
protection forests were used in erosion control. These forest areas do
more than control erosion. They help the soil to absorb and maintain
large volumes of rain-water and to release it slowly to the rivers and
springs.

China, on the other hand, presents a very striking example of the evils
which result from the inability of the administration to deal with the
whole of a great drainage unit. On the slopes of the upper reaches of
the Yellow River extensive soil erosion is constantly going on. Every
year the river transports over 2,000 million tons of soil, sufficient to
raise an area of 400 square miles by 5 feet. This is provided by the
easily erodible loess soils of the upper reaches of the catchment area.
The mud is deposited in the river bed lower down so that the embankments
which contain the stream have constantly to be raised. Periodically the
great river wins in this unequal contest and destructive inundations
result. The labour expended on the embankments is lost because the
nature of the erosion problem as a whole has not been grasped, and the
area drained by the Yellow River has not been studied and dealt with as
a single organism. The difficulty now is the over-population of the
upper reaches of the catchment area, which prevents afforestation and
laying down to grass. Had the Chinese maintained effective control of
the upper reaches--the real cause of the trouble--the erosion problem in
all probability would have been solved long ago at a lesser cost in
labour than that which has been devoted to the embankment of the river.
China, unfortunately, does not stand alone in this matter. A number of
other rivers, like the Mississippi, are suffering from overwork,
followed by periodical floods as the result of the growth of soil
erosion in the upper reaches.

Although the damage done by uncontrolled erosion all over the world is
very great, and the case for action needs no argument, nevertheless
there is one factor on the credit side which has been overlooked in the
recent literature. A considerable amount of new soil is being constantly
produced by natural weathering agencies from the sub-soil and the parent
rock. This when suitably conserved will soon re-create large stretches
of valuable land. One of the best regions for the study of this question
is the black cotton soil of Central India, which overlies the basalt.
Here, although erosion is continuous, the soil does not often disappear
altogether, for the reason that as the upper layers are removed by rain,
fresh soil is re-formed from below. The large amount of earth so
produced is well seen in the Gwalior State, where the late Ruler
employed an irrigation officer, lent by the Government of India, to
construct a number of embankments, each furnished with spillways, across
many of the valleys, which had suffered so badly by uncontrolled
rain-wash in the past that they appeared to have no soil at all, the
scrub vegetation just managing to survive in the crevices of the bare
rock. How great is the annual formation of new soil, even in such
unpromising circumstances, must be seen to be believed. In a very few
years, the construction of embankments was followed by stretches of
fertile land which soon carried fine crops of wheat. A brief illustrated
account of the work done by the late Maharaja of Gwalior would be of
great value at the moment for introducing a much needed note of optimism
in the consideration of this soil erosion problem. Things are not quite
so hopeless as they are often made to appear.

Why is the forest such an effective agent in the prevention of soil
erosion and in feeding the springs and rivers? The forest does two
things: (1) the trees and undergrowth break up the rainfall into fine
spray and the litter on the ground protects the soil from erosion; (2)
the residues of the trees and animal life met with in all woodlands are
converted into humus, which is then absorbed by the soil underneath,
increasing its porosity and water-holding power. The soil cover and the
soil humus together prevent erosion and at the same time store large
volumes of water. These factors--soil protection, soil porosity, and
water retention--conferred by the living forest cover, provide the key
to the solution of the soil erosion problem. All other purely mechanical
remedies such as terracing and drainage are secondary matters, although
of course important in their proper place. The soil must have as much
cover as possible; it must be well stocked with humus so that it can
drink in and retain the rainfall. It follows, therefore, that in the
absence of trees there must be a grass cover, some cover-crop, and ample
provision for keeping up the supply of humus. Each field so provided
suffers little or no erosion. This confirms the view of Williams
(Timiriasev Academy, Moscow) who, before erosion became important in the
Soviet Union, advanced an hypothesis that the decay of past
civilizations was due to a decline in soil fertility, consequent on the
destruction of the soil's crumb structure when the increasing demands of
civilization necessitated the wholesale ploughing up of grass-land.
Williams regarded grass as the basis of all agricultural land
utilization and the soil's chief weapon against the plundering instincts
of humanity. His views are exerting a marked influence on soil
conservation policy in the U.S.S.R. and indeed apply to many other
countries.

Grass is a valuable factor in the correct design and construction of
surface drains. Whenever possible these should be wide, very shallow,
and completely grassed over. The run-off then drains away as a thin
sheet of clear water, leaving all the soil particles behind. The grass
is thereby automatically manured and yields abundant fodder. This simple
device was put into practice at the Shahjahanpur Sugar Experiment
Station in India. The earth service roads and paths were excavated so
that the level was a few inches below that of the cultivated area. They
were then grassed over, becoming very effective drains in the rainy
season, carrying off the excess rainfall as clear water without any loss
of soil.

If we regard erosion as the natural consequence of improper methods of
agriculture, and the catchment area of the river as the natural unit for
the application of soil conservation methods, the various remedies
available fall into their proper place. The upper reaches of each river
system must be afforested; cover crops including grass and leys must be
used to protect the arable surface whenever possible; the humus content
of the soil must be increased and the crumb structure restored so that
each field can drink in its own rainfall; over-stocking and over-grazing
must be prevented; simple mechanical methods for conserving the soil and
regulating the run-off, like terracing, contour cultivation and contour
drains, must be utilized. There is, of course, no single anti-erosion
device which can be universally adopted. The problem must, in the nature
of things, be a local one. Nevertheless, certain guiding principles
exist which apply everywhere. First and foremost is the restoration and
maintenance of soil fertility, so that each acre of the catchment area
can do its duty by absorbing its share of the rainfall.


THE FORMATION OF ALKALI LANDS

When the land is continuously deprived of oxygen the plant is soon
unable to make use of it: a condition of permanent infertility results.

In many parts of the tropics and sub-tropics agriculture is interfered
with by accumulations of soluble salts composed of various mixtures of
the sulphate, chloride, and carbonate of sodium. Such areas are known as
alkali lands. When the alkali phase is still in the mild or incipient
stage, crop production becomes difficult and care has to be taken to
prevent matters from getting worse. When the condition is fully
established, the soil dies; crop production is then out of the question.
Alkali lands are common in Central Asia, India, Persia, Iraq, Egypt,
North Africa, and the United States.

At one period it was supposed that alkali soils were the natural
consequences of a light rainfall, insufficient to wash out of the land
the salts which always form in it by progressive weathering of the rock
powder of which all soils largely consist. Hence alkali lands were
considered to be a natural feature of arid tracts, such as parts of
north-west India, Iraq, and northern Africa, where the rainfall is very
small. Such ideas on the origin and occurrence of alkali lands do not
correspond with the facts and are quite misleading. The rainfall of the
Province of Oudh, in India, for example, where large stretches of alkali
lands naturally occur, is certainly adequate to dissolve the
comparatively small quantities of soluble salts found in these infertile
areas, if their removal were a question of sufficient water only. In
North Bihar the average rainfall, in the sub-montane tracts where large
alkali patches are common, is about 50 to 60 inches a year. Arid
conditions, therefore, are not essential for the production of alkali
soils; heavy rainfall does not always remove them. What is a necessary
condition is impermeability. In India whenever the land loses its
porosity, by the constant surface irrigation of stiff soils with a
tendency to impermeability, by the accumulation of stagnant subsoil
water, or through some interference with the surface drainage, alkali
salts sooner or later appear. Almost any agency, even overcultivation
and over-stimulation by means of artificial manures, both of which
oxidize the organic matter and slowly destroy the crumb structure, will
produce alkali land. In the neighbourhood of Pusa in North Bihar, old
roads and the sites of bamboo clumps and of certain trees such as the
tamarind (Tamarindus indica L.) and the pipul (Ficus religiosa L.),
always give rise to alkali patches when they are brought into
cultivation. The densely packed soil of such areas invariably shows the
bluish-green markings which are associated with the activities of those
soil organisms which live in badly aerated soils without a supply of
free oxygen. A few inches below the alkali patches, which occur on the
stiff loess soils of the Quetta Valley, similar bluish-green and brown
markings always occur. In the alkali zone in North Bihar, wells have
always to be left open to the air, otherwise the water is contaminated
by sulphuretted hydrogen, thereby indicating a well-marked reductive
phase in the deeper layers. In a sub-soil drainage experiment on the
black soils of the Nira valley in Bombay where perennial irrigation was
followed by the formation of alkali land, Mann and Tamhane found that
the salt water which ran out of these drains soon smelt strongly of
sulphuretted hydrogen, and a white deposit of sulphur was formed at the
mouth of each drain, proving how strong were the reducing actions in
this soil. Here the reductive phase in alkali formation was
unconsciously demonstrated in an area where alkali salts were unknown
until the land was water-logged by over-irrigation and the oxygen-supply
of the soil was restricted.

The view that the origin of alkali land is bound up with defective soil
aeration is supported by the recent work on the origin of saltwater
lakes in Siberia. In Lake Szira-Kul, between Bateni and the mountain
range of Kizill Kaya, Ossendowski observed in the black ooze taken from
the bottom of the lake and in the water a certain distance from the
surface an immense network of colonies of sulphur bacilli which gave off
large quantities of sulphuretted hydrogen and so destroyed practically
all the fish in this lake. The great water basins in Central Asia are
being metamorphosed in a similar way into useless reservoirs of salt
water, smelling strongly of hydrogen sulphide. In the limans near Odessa
and in portions of the Black Sea, a similar process is taking place. The
fish, sensing the change, are slowly leaving this sea as the layers of
water, poisoned by sulphuretted hydrogen, are gradually rising towards
the surface. The death of the lakes scattered over the immense plains of
Asia and the destruction of the impermeable soils of this continent from
alkali salt formation are both due to the same primary cause--intense
oxygen starvation. Often this oxygen starvation occurs naturally; in
other cases it follows perennial irrigation.

The stages in the development of the alkali condition are somewhat as
follows. The first condition is an impermeable soil. Such soils--the
usar plains of northern India for example--occur naturally where the
climatic conditions favour those biological and physical factors which
destroy the soil structure by disintegrating the compound particles into
their ultimate units. These latter are so extremely minute and so
uniform in size that they form with water a mixture possessing some of
the properties of colloids which, when dry, pack into a hard dry mass,
practically impermeable to water and very difficult to break up. Such
soils are very old. They have always been impermeable and have never
come into cultivation.

In addition to the alkali tracts which occur naturally a number are in
course of formation as the result of errors in soil management, the
chief of which are:

(a) The excessive use of irrigation water. This gradually destroys the
binding power of the organic cementing matter which glues the soil
particles together, and displaces the soil air. Anaerobic changes,
indicated by blue and brownish markings, first occur in the lower layers
and finally lead to the death of the soil. It is this slow destruction
of the living soil that must be prevented if the existing schemes of
perennial irrigation are to survive. The process is taking place before
our eyes to-day in the Canal Colonies of India where irrigation is
loosely controlled.

(b) Over-cultivation without due attention to the replenishment of
humus. In those continental areas like the Indo-Gangetic plain, where
the risk of alkali is greatest, the normal soils contain only a small
reserve of humus, because the biological processes which consume organic
matter are very intense at certain seasons due to sudden changes from
low to very high temperatures and from intensely dry weather to periods
of moist tropical conditions. Accumulations of organic matter such as
occur in temperate zones are impossible. There is, therefore, a very
small margin of safety. The slightest errors in soil management will not
only destroy the small reserve of humus in the soil but also the organic
cement on which the compound soil particles and the crumb structure
depend.

The result is impermeability, the first stage in the formation of alkali
salts.

(c) The use of artificial manures, particularly sulphate of ammonia. The
presence of additional combined nitrogen in an easily assimilable form
stimulates the growth of fungi and other organisms which, in the search
for the organic matter needed for energy and for building up microbial
tissue, use up first the reserve of soil humus and then the more
resistant organic matter which cements the soil particles. Ordinarily
this glue is not affected by the processes going on in a normally
cultivated soil, but it cannot withstand the same processes when
stimulated by dressings of artificial manures.

Alkali land therefore starts with a soil in which the oxygen-supply is
permanently cut off. Matters then go from bad to worse very rapidly. All
the oxidation factors which are essential for maintaining a healthy soil
cease. A new soil flora--composed of anaerobic organisms which obtain
their oxygen from the substratum--is established. A reduction phase
ensues. The easiest source of oxygen--the nitrates--is soon exhausted.
The organic matter then undergoes anaerobic fermentation. Sulphuretted
hydrogen is produced as the soil dies, just as in the lakes of Central
Asia. The final result of the chemical changes that take place is the
accumulation of the soluble salts of alkali land--the sulphate,
chloride, and carbonate of sodium. When these salts are present in
injurious amounts they appear on the surface in the form of snow-white
and brownish-black incrustations. The former (white alkali) consists
largely of the sulphate and chloride of sodium, and the latter (the
dreaded black alkali) contains sodium carbonate in addition and owes its
dark colour to the fact that this salt is able to dissolve the organic
matter in the soil and produce physical conditions which render drainage
impossible. According to Hilgard, sodium carbonate is formed from the
sulphate and chloride in the presence of carbon dioxide and water. The
action is reversed in the presence of oxygen. Subsequent investigations
have modified this view and have shown that the formation of sodium
carbonate in soil takes place in stages. The appearance of this salt
always marks the end of the chapter. The soil is dead. Reclamation then
becomes difficult on account of the physical conditions set up by these
alkali salts and the dissolved organic matter.

The occurrence of alkali land, as would be expected from its origin, is
extremely irregular. When ordinary alluvial soils like those of the
Punjab and Sind are brought under perennial irrigation, small patches of
alkali first appear where the soil is heavy; on stiffer areas the
patches are large and tend to run together. On open permeable stretches,
on the other hand, there is no alkali. In tracts like the Western
Districts of the United Provinces, where irrigation has been the rule
for a long period, zones of well-aerated land carrying fine irrigated
crops occur alongside the barren alkali tracts. Iraq also furnishes
interesting examples of the connexion between alkali and poor soil
aeration. Intensive cultivation under irrigation is only met with in
that country where the soils are permeable and the natural drainage is
good. Where the drainage and aeration are poor, the alkali condition at
once becomes acute. There are, of course, a number of irrigation
schemes, such as the staircase cultivation of the Hunzas in northwest
India and of Peru, where the land has been continually watered from time
immemorial without any development of alkali salts. In Italy and
Switzerland perennial irrigation has been practiced for long periods
without harm to the soil. In all such cases, however, careful attention
has been paid to drainage and aeration and to the maintenance of humus;
the soil processes have been confined by Nature or by man to the
oxidative phase; the cement of the compound particles has been protected
by keeping up a sufficiency of organic matter.

Every possible gradation in alkali land is met with. Minute quantities
of alkali salts in the soil have no injurious effect on crops or on the
soil organisms. It is only when the proportion increases beyond a
certain limit that they first interfere with growth and finally prevent
it altogether. Leguminous crops are particularly sensitive to alkali
especially when this contains carbonate of soda. The action of alkali
salts on the plant is a physical one and depends on the osmotic pressure
of solutions, which increases with the amount of the dissolved
substance. For water to pass readily from the soil into the roots of
plants, the osmotic pressure of the cells of the root must be
considerably greater than that of the soil solution outside. If the soil
solution became stronger than that of the cells, water would pass
backwards from the roots to the soil and the crops would dry up. This
state of affairs naturally occurs when the soil becomes charged with
alkali salts beyond a certain point. The crops are then unable to take
up water and death results. The roots behave like a plump strawberry
when placed in a strong solution of sugar. Like the strawberry they
shrink in size because they have lost water to the stronger solution
outside. Too much salt in the water therefore makes irrigation water
useless and destroys the canal as a commercial proposition.

The reaction of the crop to the first stages in alkali production is
interesting. For twenty years at Pusa and eight years in the Quetta
Valley I had to farm land, some of which hovered, as it were, on the
verge of alkali. The first indication of the condition is a darkening of
the foliage and the slowing down of growth. Attention to soil aeration,
to the supply of organic matter, and to the use of deep-rooting crops
like lucerne and pigeon pea, which break up the sub-soil, soon sets
matters right. Disregard of Nature's danger signals, however, leads to
trouble--a definite alkali patch is formed. When cotton is grown under
canal irrigation on the alluvial soils of the Punjab, the reaction of
the plant to incipient alkali is first shown by the failure to set seed,
on account of the fact that the anther, the most sensitive portion of
the flower, fails to function and to liberate its pollen. The cotton
plant naturally finds it difficult to obtain from mild alkali soil all
the water it needs--this shortage is instantly reflected in the
breakdown of the floral mechanism.

The theory of the reclamation of alkali land is very simple. All that is
needed, after treating the soil with sufficient gypsum (which transforms
the sodium clays into calcium clays), is to wash out the soluble salts,
to add organic matter, and then to farm the land properly. Such
reclaimed soils are then exceedingly fertile and remain so. If
sufficient water is available it is sometimes possible to reclaim alkali
soils by washing only. I once confirmed this. The berm of a raised water
channel at the Quetta Experiment Station was faced with rather heavy
soil from an alkali patch. The constant passage of the irrigation water
down the water channel soon removed the alkali salts. This soil then
produced some of the heaviest crops of grass I have ever seen in the
tropics. When, however, the attempt is made to reclaim alkali areas on a
field scale, by flooding and draining, difficulties at once arise unless
steps are taken first to replace all the sodium in the soil complex by
calcium and then to prevent the further formation of sodium clays. Even
when these reclamation methods succeed, the cost is always considerable;
it soon becomes prohibitive; the game is not worth the candle. The
removal of the alkali salts is only the first step; large quantities of
organic matter are then needed; adequate soil aeration must be provided;
the greatest care must be taken to preserve these reclaimed soils and to
see that no reversion to the alkali condition occurs. It is exceedingly
easy under canal irrigation to create alkali salts on certain areas. It
is exceedingly difficult to reverse the process and to transform alkali
land back again into a fertile soil.

Nature has provided, in the shape of alkali salts, a very effective
censorship for all schemes of perennial irrigation. The conquest of the
desert, by means of the canal, by no means depends on the mere provision
of water and arrangements for the periodical flooding of the surface.
This is only one of the factors of the problem. The water must be used
in such a manner and the soil management must be such that the fertility
of the soil is maintained intact. There is obviously no point in
creating, at vast expense, a Canal Colony and producing crops for a
generation or two, followed by a desert of alkali land. Such an
achievement merely provides another example of agricultural banditry. It
must always be remembered that the ancient irrigators never developed
any efficient method of perennial irrigation, but were content with the
basin system, a device by which irrigation and soil aeration can be
combined. (The land is embanked; watered once; when dry enough it is
cultivated and sown. In this way water can be provided without any
interference with soil aeration.) In his studies on irrigation and
drainage, King concludes an interesting discussion of this question in
the following words, which deserve the fullest consideration on the part
of the irrigation authorities all over the world:


'It is a noteworthy fact that the excessive development of alkalis in
India, as well as in Egypt and California, is the result of irrigation
practices modern in their origin and modes and instituted by people
lacking in the traditions of the ancient irrigators, who had worked
these same lands thousands of years before. The alkali lands of to-day,
in their intense form, are of modern origin, due to practices which are
evidently inadmissible, and which in all probability were known to be
so by the people whom our modern civilization has supplanted.'



BIBLIOGRAPHY


SOIL EROSION

GORRIE, R. M. 'The Problem of Soil Erosion in the British Empire,
with special reference to India', Journal of the Royal Society
of Arts, lxxxvi, 1938, p. 901.

HOWARD, SIR ALBERT. 'A Note on the Problem of Soil Erosion', Journal
of the Royal Society of Arts, lxxxvi, 1938, p.
926.

JACKS, G. V., and WHYTE, R. O. Erosion and Soil Conservation, Bulletin 25,
Imperial Bureau of Pastures and Forage Crops, Aberystwyth, 1938.

------The Rape of the Earth: A World Survey of Soil Erosion, London, 1939.

Soils and Men, Year Book of Agriculture, 1938, U.S. Dept. of Agr.,
Washington, D.C., 1938.


ALKALI SOILS

HILGARD, E. W. Soils, New York, 1906.

HOWARD, A. Crop Production in India, Oxford University Press, 1924.

KING, F. H. Irrigation and Drainage, London, 1900.

OSSENDOWSKI, F. Man and Mystery in Asia, London, 1924.

RUSSELL, SIR JOHN. Soil Conditions and Plant Growth, London, 1937.




CHAPTER XI



THE RETREAT OF THE CROP AND THE ANIMAL BEFORE THE PARASITE


In the previous chapter we have seen how Nature, by means of soil
erosion, removes any area of worn-out land and recreates new soil in a
fresh place. Mismanagement of the land is followed later on by a New
Deal, as it were, somewhere else. A similar rule applies to crops: the
diseased crop is quietly but effectively labelled prior to removal for
the manufacture of humus, so that the next generation of plants may
benefit.

Mother earth has provided a vast organization for indicating the
inefficient crop. Where the soil is infertile, where an unsuitable
variety is being grown, or where some mistake has been made in
management, Nature at once registers her disapproval through her
Censors' Department. One or more of the groups of parasitic insects and
fungi--the organisms which thrive on unhealthy living matter--are told
off to point out that farming has failed. In the conventional language
of to-day the crop is attacked by disease. In the writings of the
specialist, a case has arisen for the control of a pest: a crop must be
protected.

In recent years another form of disease--known as virus disease--has
made its appearance. There is no obvious parasite in virus diseases, but
insects among other agencies are able to transmit the trouble from
diseased to apparently healthy plants in the neighbourhood. When the
cell contents of affected plants are examined, the proteins exhibit
definite abnormalities, thereby suggesting that the work of the green
leaf is not effective; the synthesis of albuminoids seems to be
incomplete. With the development of special research laboratories, like
that at Cambridge, more and more of these diseases are being discovered
and a considerable literature on the subject has arisen.

The virus diseases do not complete the story. A certain number of
maladies occur in which the apparent cause is neither a fungus, an
insect, nor a virus. These are grouped under the general
title--physiological diseases: troubles arising from the collapse of the
normal metabolic processes.

How has agricultural science dealt with the diseases of crops? The
answer is both interesting and illuminating. The subject has been
approached in a variety of ways, which can be briefly summed up under
the following four heads:

1. The study of the life history of the pest, including the general
relation of the parasite to the crop and the influence of the
environment on the struggle for supremacy between the two. The main
object of these investigations has been to discover some possible
weakness in the life history of the pest which can be utilized to
destroy it or to protect the plant from infection. An impressive volume
of specialist literature has resulted. As the number of investigators
grows and as their inquiries become more exhaustive and tend to cover a
rapidly increasing proportion of the earth's surface, there is a
corresponding increase in the volume of print. It is now almost
impossible to take up any of the periodicals dealing with agricultural
research without finding at least one long illustrated article
describing some new disease. So vast has the literature become that the
specialists themselves are unable to cope with it. Most of it can only
be read by the workers in abstract, for which again new agencies have
been created in the British Empire--the Imperial Bureaux of Entomology
and Mycology--bodies which act as clearing-houses of information and
deal with the published papers in a way reminiscent of the methods of
the Banker's Clearing House in dealing with cheques.

2. The study of the natural parasites of insect pests, the breeding of
these animals, and their actual introduction whenever this procedure
promises success. A separate institution for this purpose has been
founded at Farnham Royal in Buckinghamshire.

3. The protection of the crop from the inroads of the parasite. As a
rule this takes two forms: (1) the discovery of insecticides and
fungicides and the design of the necessary machinery for covering the
crop with a thin film of poison which will destroy the parasite in the
resting stage or before it can gain entry to the host; (2) the
destruction of the parasite by burning, by the use of corrosive liquids
like strong sulphuric acid, or by germicides added to the soil so that
the amount of infecting material will be negligible.

4. The framing and conduct of regulations to protect an area from some
foreign pest which has not yet made its appearance. These follow the
usual methods of quarantine. Importation of plants and seeds is
prohibited altogether, introduction is permitted under licence, or the
plant material is inspected and fumigated at the port of entry. The
principle in all cases is the same--the crops must be protected from
chance infection by some foreign parasite which might cause untold
damage. As traffic by land, sea, and air grows in volume and becomes
speeded up, it will be increasingly difficult to enforce these
regulations. It is impossible even now to inspect all luggage and all
merchandise and to prevent the smuggling of small packets of seed or
cuttings of living plants. Indeed, if an investigation were to be made
of the personal effects of the coolies passing backwards and forwards
between India and Burma, India and the Federated Malay States and
Ceylon, it would be seen what an extraordinary collection of articles
these men and women carry about and how frequently plants and seeds are
included. Enthusiasts in gardening often collect plants on their travels
which interest them. The population, live stock, and factories of Great
Britain are partly supplied with seeds from all over the world. By one
or other of these agencies a few new pests are almost certain from time
to time to enter the country. These quarantine methods therefore can
never succeed.

More than fifty years have passed since the modern work on the diseases
of plants first began. What has been the general result of all this
study of vegetable pathology? Has it provided anything of permanent
value to agriculture? Is the game worth the candle? Must agricultural
science go on discovering more and more new pests and devising more and
more poison sprays to destroy them or is there any alternative method of
dealing with the situation? Why is there so much of this disease? Can
the growing tale of the pests of Western agriculture be accounted for by
some subtle change in practice? Can the cultivators of the East, for
example, teach us anything about diseases and their control?

In this chapter an attempt will be made to answer these interesting
questions.

It is a well-understood principle in business that any organization like
agricultural research, which has grown by accretion rather than by the
development of a considered plan, stands in need of a periodical
critical examination to ascertain whether the results obtained
correspond with the cost and whether any modifications are needed in the
light of new knowledge and experience. I began such an investigation of
the plant and animal disease section of agricultural science in 1899 and
have steadily pursued it since. After forty years' work I feel
sufficiently confident of my general conclusions to place them on
record, and to ask for them to be considered on their merits.

I took up research in agriculture as a mycologist in the West Indies in
1899, where I specialized in the diseases of sugar-cane and cacao and
became interested in tropical agriculture. Almost at once I discerned a
fundamental weakness in the research organization: the mycologist had no
land on which he could take his own advice about remedies before asking
planters to adopt them.

My next post was botanist at Wye College in Kent, where I was in charge
of the experiments on hops and had ample opportunities for studying the
insect and fungous diseases of this interesting crop. But again I had no
land on which I could try out certain ideas that were fermenting in my
mind about the prevention of hop diseases. I observed one interesting
thing: the increase in the resisting power to infection of the young hop
flower which resulted from pollination. This observation has since
brought about a change in the local practice: the male hop is now
cultivated and ample pollination of the female flowers--the hops of
commerce--occurs.

In 1905 I was appointed Imperial Economic Botanist to the Government of
India. At the Pusa Agricultural Research Institute, largely through the
support of the Director, the late Mr. Bernard Coventry, I had for the
first time all the essentials for work--interesting problems, money,
freedom, and, last but nit least, 75 acres of land on which I could grow
crops in my own way and study their reaction to insect and fungous pests
and other things. My real training in agricultural research then
began--six years after leaving the University and obtaining all the
paper qualifications and academic experience then needed by an
investigator.

At the beginning of this second and intensive phase of my training, I
resolved to break new ground and try out an idea (which first occurred
to me in the West Indies), namely, to observe what happened when insect
and fungous diseases were left alone and allowed to develop unchecked,
and where indirect methods only, such as improved cultivation and more
efficient varieties, were employed to prevent attack. This point of view
derived considerable impetus from a preliminary study of Indian
agriculture. The crops grown by the cultivators in the neighbourhood of
Pusa were remarkably free from pests of all kinds; such things as
insecticides and fungicides found no place in this ancient system of
agriculture. I decided that I could not do better than watch the
operations of these peasants, and acquire their traditional knowledge as
rapidly as possible. For the time being, therefore, I regarded them as
my professors of agriculture. Another group of instructors were
obviously the insects and fungi themselves. The methods of the
cultivators if followed would result in crops practically free from
disease; the insects and fungi would be useful for pointing out
unsuitable varieties and methods of farming inappropriate to the
locality.

It was possible for me to approach the subject of plant diseases in this
unorthodox manner for two reasons. In the first place the Agricultural
Research Institute at Pusa was little more than a name when I arrived in
India in 1905. Everything was fluid; there was nothing in the nature of
an organized system of research in existence. In the second place, my
duties, fortunately for me, had not been clearly defined. I was
therefore able to break new ground, to widen the scope of economic
botany until it became crop production, to base my investigations on a
first-hand knowledge of Indian agriculture, and to take my own advice
before offering it to other people. In this way I escaped the fate of
the majority of agricultural investigators--the life of a laboratory
hermit devoted to the service of an obsolete research organization.
Instead, I spent my first five years in India ascertaining by practical
experience the principles underlying health in crops.

In order to give my crops every chance of being attacked by parasites,
nothing was done in the way of prevention; no insecticides and
fungicides were used; no diseased material was ever destroyed. As my
understanding of Indian agriculture progressed, and as my practice
improved, a marked diminution of disease occurred. At the end of five
years' tuition under my new professors--the peasants and the pests--the
attacks of insects and fungi on all crops, whose root systems were
suitable to the local soil conditions, became negligible. By 1910 I had
learnt how to grow healthy crops, practically free from disease, without
the slightest help from mycologists, entomologists, bacteriologists,
agricultural chemists, statisticians, clearing-houses of information,
artificial manures, spraying machines, insecticides, fungicides,
germicides, and all the other expensive paraphernalia of the modern
Experiment Station.

I then posed to myself the principles which appeared to underlie the
diseases of plants:

1. Insects and fungi are not the real cause of plant diseases but only
attack unsuitable varieties or crops imperfectly grown. Their true role
is that of censors for pointing out the crops that are improperly
nourished and so keeping our agriculture up to the mark. In other words,
the pests must be looked upon as Nature's professors of agriculture: as
an integral portion of any rational system of farming.

2. The policy of protecting crops from pests by means of sprays,
powders, and so forth is unscientific and unsound as, even when
successful, such procedure merely preserves the unfit and obscures the
real problem--how to grow healthy crops.

3. The burning of diseased plants seems to be the unnecessary
destruction of organic matter as no such provision as this exists in
Nature, in which insects and fungi after all live and work.

This preliminary exploration of the ground suggested that the birthright
of every crop is health, and that the correct method of dealing with
disease at an Experiment Station is not to destroy the parasite, but to
make use of it for tuning up agricultural practice.

Steps were then taken to apply these principles to oxen, the power unit
in Indian agriculture. For this purpose it was necessary to have the
work cattle under my own charge, to design their accommodation, and to
arrange for their feeding, hygiene, and management. At first this was
refused, but after persistent importunity, backed by the powerful
support of the Member of the Viceroy's Council in charge of agriculture
(the late Sir Robert Carlyle, K.C.S.I.), I was allowed to have charge of
six pairs of oxen. I had little to learn in this matter as I belong to
an old agricultural family and was brought up on a farm which had made
for itself a local reputation in the management of cattle. My work
animals were most carefully selected and everything was done to provide
them with suitable housing and with fresh green fodder, silage, and
grain, all produced from fertile land. I was naturally intensely
interested in watching the reaction of these well-chosen and well-fed
oxen to diseases like rinderpest, septicaemia, and foot-and-mouth
disease which frequently devastated the countryside. These epidemics are
the result of starvation, due to the intense pressure of the bovine
population on the limited food-supply. None of my animals were
segregated; none were inoculated; they frequently came in contact with
diseased stock. As my small farm-yard at Pusa was only separated by a
low hedge from one of the large cattle-sheds on the Pusa estate, in
which outbreaks of foot-and-mouth disease often occurred, I have several
times seen my oxen rubbing noses with foot-and-mouth cases. Nothing
happened. The healthy well-fed animals reacted to this disease exactly
as suitable varieties of crops, when properly grown, did to insect and
fungous pests--no infection took place.

As the factors of time and place are important when testing any
agricultural innovation, it now became necessary to try out the three
principles referred to above over a reasonably long period and in new
localities. This was done during the next twenty-one years at three
centres: Pusa (1910-24), Quetta (summers of 1910-18), and Indore
(1924-31).

At Pusa, during the years 1910 to 1924, outbreaks of plant diseases were
rare, except on certain cultures with deep root systems which were grown
chiefly to provide a supply of infecting material for testing the
disease resistance of new types obtained by plant-breeding methods. Poor
soil aeration always encouraged disease at Pusa. The unit species of
Lathyras sativus provided perhaps the most interesting example of the
connexion between soil aeration and insect attack. These unit species
fell into three groups: surface-rooted types always immune to green-fly;
deep-rooted types always heavily infected; types with intermediate root
system always moderately infected. These sets of cultures were grown
side by side year after year in small oblong plots about 10 feet wide.
The green-fly infection repeated itself each year and was determined not
by the presence of the parasite, but by the root development of the
host. Obviously the host had to be in a certain condition before
infection could take place. The insect, therefore, was not the cause but
the consequence of something else.

One of the crops under study at Pusa was tobacco. At first a great many
malformed plants--since proved to be due to virus--made their appearance
in my cultures. When care was devoted to the details of growing tobacco
seed, to the raising of the seedlings in the nurseries, to transplanting
and general soil management, this virus disease disappeared altogether.
It was very common during the first three years; it then became
infrequent; between 1910 and 1924 I never saw a single case. Nothing was
done in the way of prevention beyond good farming methods and the
building up of a fertile soil. I dismissed it at the time as one of the
many mare's nests of agricultural science--things which have no real
existence.

For a period of eight years, I was provided with a subsidiary experiment
station on the loess soils of the Quetta valley for the study of the
problems underlying fruit-growing and irrigation. I observed no fungous
disease of any importance in the dry climate of the Quetta valley during
the eight summers I spent there. In the grape gardens, run by the
tribesmen on the well-drained slopes of the valley, I never observed any
diseases--insect or fungous--on the grapes or on the vines, although
they were planted on the floors of deep trenches, allowed to climb up
the earth walls and were frequently irrigated. At first sight, all the
conditions for mildew seemed to have been provided, yet I never saw a
single speck. Three favourable factors probably accounted for this
result. The climate was exceedingly dry, with considerable air movement
and cloudless skies; the soil made use of by the roots of the vine was
open, well drained, and exceptionally well aerated; the only manure used
was farm-yard manure. Growth, yield, quality, and disease resistance
left nothing to be desired.

The chief pest of fruit-trees at Quetta was green-fly soon after the
young leaves appeared. This could be produced or avoided at will by
careful attention to cultivation and irrigation. Any interference with
soil aeration brought on this trouble; anything which promoted soil
aeration prevented it. I frequently produced a strong attack of
green-fly on peaches and almonds by over-irrigation during the winter
and spring, and then stopped it dead by deep cultivation. The young
shoots were covered with the pest below, but the upper portions of the
same shoots were completely healthy. The green-fly never spread from the
lower to the upper leaves on the same twig. The tribesmen got over the
tendency of these loess soils to pack under irrigation in a very simple
way. Lucerne was always grown in the fruit orchards, and regularly
top-dressed with farm-yard manure. In this way the porosity of the soil
was maintained and the green-fly kept in check.

At the Institute of Plant Industry, Indore, only two cases of disease
occurred during the eight years I was there. The first occurred on a
small field of gram (Cicer arietinum), about two-thirds of which was
flooded for a few days one July, due to the temporary stoppage of one of
the drainage canals which took storm water from adjacent areas through
the estate. A map of the flooded area was made at the time. In October,
about a month after sowing, this plot was heavily attacked by the gram
caterpillar, the insectinfected area corresponding exactly with the
inundation area. The rest of the plot escaped infection and grew
normally. The insect did not spread to the other 50 acres of gram grown
that year alongside. Some change in the food of the caterpillar had
obviously been brought about by the alteration in the soil conditions
caused by the temporary flooding. The second case of disease occurred in
a field of san hemp (Crotalaria juncea L.) intended for green-manuring;
however, this was not ploughed in but was kept for seed. After flowering
the crop was smothered by a mildew; no seed was harvested. To produce a
crop of seed of san on the black soils, it is necessary to manure the
land with humus or farm-yard manure, when no infection takes place and
an excellent crop of seed is obtained.

One experiment with cotton unfortunately could not be arranged in spite
of all my efforts. At Indore there was a remarkable absence of all
insect and fungous diseases of cotton. Good soil management, combined
with dressings of humus, produced crops which were practically immune to
all the pests of cotton. When the question of protecting India from the
various cotton boll-worms and boll-weevils from America was discussed, I
offered to have these let loose among my cotton cultures at Indore in
order (1) to settle the question whether these troubles in the U.S.A.
were due to the insect or to the way the cotton was grown, and (2) to
subject my farming methods to a crucial test. I am pretty certain the
insects would have found my cotton cultures very indifferent
nourishment. My proposal, however, did not find favour with the
entomological advisers of the Indian Cotton Committee and the matter
dropped.

At Quetta and Indore there was no case of infectious disease among the
oxen. The freedom from disease observed at Pusa was again experienced in
the new localities--the Western Frontier and Central India.

It was soon discovered in the course of this work that the thing that
matters most in crop production is a regular supply of well-made
farm-yard manure and that the maintenance of soil fertility is the basis
of health.


HUMUS AND DISEASE RESISTANCE

Even on the Experiment Stations the supply of farm-yard manure was
always insufficient. The problem was how to increase it in a country
where a good deal of the cattle-dung has to be burnt for fuel. The
solution of this problem was suggested by the age-long practices of
China. It involved the study of how best to convert the animal and
vegetable wastes into humus, so that every holding in India could become
self-supporting as regards manure. Such a problem did not fall within my
sphere of work--the improvement of crops. It obviously necessitated a
great deal of chemical work under my personal control. The organization
of research at Pusa had gradually become more rigid; the old latitude
which existed in the early days became a memory. That essential freedom,
without which no progress is possible, had been gradually destroyed by
the growth of a research organization based on fragments of science
rather than on the practical problems which needed investigation. The
instrument became more important than its purpose. Such organizations
can only achieve their own destruction. This was the reason why I
decided to leave Pusa and found a new centre where I should be free to
follow the gleam unhampered and undisturbed. After a delay of six years,
1918 to 1924, the Indore Institute was founded. In due course a simple
method, known as the Indore Process, of composting vegetable and animal
wastes was devised, tested, and tried out on the 300 acres of land at
the disposal of the Institute of Plant Industry, Indore. In a few years
production more than doubled: the crops were to all intents and purposes
immune from disease.

Since 1931 steps have been taken to get the Indore Process taken up in a
number of countries, especially by the plantation industries such as
coffee, tea, sugar, sisal, maize, cotton, tobacco, and rubber. The
results obtained have already been discussed. In all these trials the
conversion of vegetable and animal wastes into humus has been followed
by a definite improvement in the health of the crops and of the live
stock. My personal experience in India has been repeated all over the
world. At the same time a number of interesting problems have been
unearthed. One example will suffice. In Rhodesia humus protects the
maize crop from the attacks of the witchweed (Striga lutea). Is this
infestation a consequence of malnutrition? Is immunity conferred by the
establishment of the mycorrhizal association? Answers to these questions
would advance our knowledge and would suggest a number of fascinating
problems for investigation.


THE MYCORRHIZAL ASSOCIATION AND DISEASE

Why is humus such an important factor in the health of the crop? The
mycorrhizal association provides the clue. The steps by which this
conclusion was reached in the case of tea have already been stated.

This association is not confined to one particular forest crop. It
occurs in most if not all our cultivated plants. During 1938 Dr. Rayner
and Dr. Levisohn examined and reported on a large number of my
samples--rubber, coffee, cacao, leguminous shade trees, green-manure
crops, coco-nuts, lung, cardamons, vine, banana, cotton, sugar-cane,
hops, strawberries, bulbs, grasses and clovers and so forth. In all of
these the mycorrhizal association occurs. It is probably universal. We
appear to be dealing with a very remarkable example of symbiosis in
which certain soil fungi directly connect the humus in the soil with the
roots of the crop. This fungous tissue may contain as much as 10 per
cent. of nitrogen in the form of protein, which is digested in the
active roots and probably carried by the transpiration current to the
seat of carbon assimilation in the green leaves. Its effective presence
in the roots of the plant is associated with health; its absence is
associated with diminished resistance to disease. Clearly the first step
in investigating any plant disease in the future will be to see that the
soil is fertile and that this fungous association is in full working
order. If it is as important as is now suggested, there will be a marked
improvement in the behaviour of the host once the fertility of the soil
is restored. If it has no significance, a fertile soil will make no
difference.

I have just obtained confirmatory results which prove how important
humus is in helping a mycorrhiza-former--the apple--to throw off
disease. In 1935 I began the restoration, by means of humus, of my own
garden, the soil of which was completely worn-out when I acquired it in
the summer of 1934. The apple trees were literally smothered with
American blight, green-fly, and fruit-destroying caterpillars like the
codlin moth. The quality of the fruit was poor. Nothing was done to
control these pests beyond the gradual building up of the humus content
of the soil. In three years the parasites disappeared; the trees were
transformed; the foliage and the new wood now leave nothing to be
desired; the quality of the fruit is first class. These trees will now
be used for infection experiments in order to ascertain whether the
fertility of the soil has been completely restored or not. The reaction
of the trees to the various pests of the apple will answer this
question. No soil analysis can tell me as much as the trees will.

The meaning of all this is clear. Nature has provided a marvellous piece
of machinery for conferring disease-resistance on the crop. This
machinery is only active in soil rich in humus; it is inactive or absent
in infertile land and in similar soils manured with chemicals. The fuel
needed to keep this machinery in motion is a regular supply of freshly
prepared humus, properly made. Fertile soils then yield crops resistant
to disease. Worn-out soils, even when stimulated with chemical manures,
result in produce which needs the assistance of insecticides and
fungicides to yield a crop at all. These in broad outline are the facts.

The complete scientific explanation of the working of this remarkable
example of symbiosis remains to be provided. It would appear that in the
mycorrhizal association Nature has given us a mechanism far more
important and far more universal than the nodules on the roots of the
clover family. It reconciles at one bound science and the age-long
experience of the tillers of the soil as to the supreme importance of
humus. There has always been a mental reservation on the part of the
best farmers as to the value of artificial manures compared with good
old-fashioned muck. The effect of the two on the soil and on the crop is
never quite the same. Further, there is a growing conviction that the
increase in plant and animal diseases is somehow connected with the use
of artificials. In the old days of mixed farming the spraying machine
was unknown, the toll taken by troubles like foot-and-mouth disease was
insignificant compared with what it is now. The clue to all these
differences--the mycorrhizal association--has been there all the time.
It was not realized because the experiment stations have blindly
followed the fashion set by Liebig and Rothamsted in thinking only of
soil nutrients and have forgotten to look at the way the plant and the
soil come into gear. An attempt has been made to apply science to a
biological problem by means of one fragment of knowledge only.


THE INVESTIGATIONS OF TO-MORROW

The next step in this investigation is to test the soundness of the
views put forward. This has been started by composting diseased material
and then using the humus to grow another crop on the same land. Diseased
tomatoes have been converted into humus by one of the large growers in
the south of England and the compost has been used to grow a second crop
in the same greenhouses. No infection occurred.

The final proof that insects, fungi, viruses and so forth are not the
cause of disease will be provided when the infection experiments of
to-morrow are undertaken. Instead of conducting these trials on plants
and animals grown anyhow, the experimental material will be plants and
animals, properly selected, efficiently managed, and nourished by or on
the produce of a fertile soil. Such plants can be sprayed with active
fungous and insect material without harm. Among such herds of cattle,
cases of foot-and-mouth disease can be introduced without any danger of
serious infection. The afflicted animals themselves will recover. When
some audacious innovator of the Hosier type, who has no interest in the
maintenance of the existing research structure, conducts such
experiments, the vast fabric of disease-control which has been erected
in countries like Great Britain will finally collapse. Farmers will
emancipate themselves from the thralldom created by the fear of the
parasite. Another step forward will be taken which will not stop at
farming.

My self-imposed task is approaching completion. I have examined in great
detail for forty years the principles underlying the treatment of plant
and animal diseases, as well as the practice based on these principles.
It now remains to sum up this experience and to offer suggestions for
the future.

There can be no doubt that the work in progress on disease at the
Experiment Stations is a gigantic and expensive failure, that its
continuance on present lines can lead us nowhere and that steps must be
taken without delay to place it on sounder lines.

The cause of this failure is not far to seek. The investigations have
been undertaken by specialists. The problems of disease have not been
studied as a whole, but have been divorced from practice, split up,
departmentalized and confined to the experts most conversant with the
particular fragment of science which deals with some organism associated
with the disease.

This specialist approach is bound to fail. This is obvious when we
consider: (1) the real problem--how to grow healthy crops and how to
raise healthy animals, and (2) the nature of disease--the breakdown of
a complex biological system, which includes the soil in its relation to
the plant and the animal. The problem must include agriculture as an
art. The investigator must therefore be a farmer as well as a scientist,
and must keep simultaneously in mind all the factors involved. Above all
he must be on his guard to avoid wasting his life in the study of a
mare's nest: in dealing with a subject which owes its existence to bad
farming which will disappear the moment sound methods of husbandry are
employed.

The problems presented by the retreat of the crop and of the animal
before the parasite and the conventional methods of investigation of
these questions are clearly out of relation. It follows therefore that a
research organization which has lost direction and has permitted such a
state of things to arise and to develop must itself be in need of
overhaul. This task has been attempted; the existing structure of
agricultural research has been subjected to a critical examination; the
results are set out in Chapter XIII.



BIBLIOGRAPHY

HOWARD, A. Crop Production in India, Oxford University Press,
1924, p. 176.

-------'The Role of Insects and Fungi in Agriculture', Empire Cotton
Growing Review, xiii, 1936, p. 186.

-------'Insects and Fungi in Agriculture', Empire Cotton Growing Review,
xv, 1938, p. 215.

TIMSON, S. D. 'Humus and Witchweed', Rhodesia Agricultural Journal,
xxxv, 1938, p. 805.




CHAPTER XII



SOIL FERTILITY AND NATIONAL HEALTH


In the last chapter the retreat of the crop and the animal before the
parasite was discussed. Disease was regarded as Nature's verdict on
systems of agriculture in which the soil is deprived of its manurial
rights. When the store of humus is used up and not replenished, both
crops and animals first cease to thrive and then often fall a prey to
disease. In other words, one of the chief causes of disease on the farm
is bad soil management.

How does the produce of an impoverished soil affect the men and women
who have to consume it? This is the theme of the present chapter. It is
discussed, not on the basis of complete results, but from the point of
view of a very promising hypothesis for future work. No other
presentation is possible because of the paucity, for the moment, of
direct evidence and the natural difficulties of the subject.

In the case of crops and live stock, experiments are easy. The
investigator is not hampered in any way; he has full control of his
material and freedom in experimentation. He cannot experiment on human
beings in the same way. The only subjects that might conceivably be used
for nutrition experiments on conventional lines are to be found in
concentration camps, in convict prisons, and in asylums. Objections to
using them for such purposes would almost certainly be raised. Even if
they were not, the investigator would be dealing with life in captivity
and with abnormal conditions. Any results obtained would not necessarily
apply to the population as a whole.

Perhaps the chief difficulty at the moment in following up the possible
connexion between the produce of a fertile soil and the health of the
people who have to consume it, is to obtain from well-farmed land
regular supplies of such produce in a perfectly fresh condition. Except
in a few cases, food is not marketed according to the way it is grown.
The buyer knows nothing of how it was manured. The only way to obtain
suitable material would be for the investigator to take up a piece of
land and grow the food itself. This, so far as my knowledge goes, has
not been done. This omission explains the scarcity of direct results and
why so little real progress has been made in human nutrition. Most of
the work of the past has been founded on the use of food material very
indifferently grown. Moreover, no particular care has been taken to see
that the food has been eaten fresh from its source. Such investigations
therefore can have no solid foundation.

Apart from the evidence that can be gathered from nutrition experiments,
is there anything to be learnt about health from agriculture itself? Can
the East which, long before the Roman Empire began or America was
discovered, had already developed the systems of good farming which are
in full swing to-day, throw any light on the relation between a fertile
soil and a healthy population? It is well known that both China and
India can show large areas of well-farmed land, which for centuries have
carried very large populations. Unfortunately two factors--overpopulation
and periodic crop failures due to irregular rainfall--make it almost
impossible to draw any general lessons from these countries. The
population, looked at in the mass, is always recovering from one
catastrophe after another. Over-population introduces a disturbing
factor--long-continued semi-starvation--so powerful in its effects
on the race and on the individual that any benefits arising from a
fertile soil are entirely obscured.

When, however, the population of the various parts of India is examined,
very suggestive differences between the races which make up its 350
million inhabitants are disclosed. The physique seen in the northern
area is strikingly superior to that of the southern, eastern, and
western tracts. We owe the investigation of the causes of these
differences to McCarrison, who found that they corresponded with the
food consumed. There is a gradually diminishing value in the food from
the north to the east, south and west in respect of the amount and
quality of the proteins, the quality of the cereal grains forming the
staple article of diet, the quantity and quality of the fats, the
mineral and vitamin content, as well as in the balance of the food as a
whole.

Generally speaking the people of northern India, which include some of
the finest races of mankind, are wheat eaters, the wheat being consumed
in the form of thin, flat cakes made from flour, coarse but fresh-ground
in a quern. All the proteins, vitamins, and mineral salts in the grain
are consumed. The second most important article of diet is fresh milk
and milk products--clarified butter, curds, and buttermilk; the third
item is the seed of pulse crops; the fourth vegetables and fruit. Meat,
as a rule, is very sparingly eaten except by the Pathans.

Turn now to the other parts of India, east, west, and south, in which
the rice tracts provide the staple food. This cereal--a relatively poor
grain at best--is parboiled, milled or polished, washed in many changes
of water, and finally boiled. It is thereby deprived of much of its
protein and mineral salts and of almost all its vitamins. In addition,
very little milk or milk products are consumed, while the protein
content of the diet is low both in amount and quality. Vegetables and
fruit are only sparingly eaten. It is these shortcomings in their food
that explain the poor physique of the peoples of the rice areas.

In order to prove that these bodily differences were due to food,
McCarrison carried out experiments on young growing rats. When young
growing rats of healthy stock were fed on diets similar to those of the
races of northern India, the health and physique of the rats were good;
when they were fed on the diets in vogue in the rice areas, the health
and physique of the rats were bad; when they were fed on the diets of
races with middling physique, the health and physique of the rats were
middling. Other things being equal, good or bad diet led to good or bad
health and physique.

When the health and physique of the various northern Indian races were
studied in detail the best were those of the Hunzas, a hardy, agile, and
vigorous people, living in one of the high mountain valleys of the
Gilgit Agency, where an ancient system of irrigated terraces has been
maintained for thousands of years in a high state of fertility. There is
little or no difference between the kinds of food eaten by these hillmen
and by the rest of northern India. There is, however, a great difference
in the way these foods are grown. The total area of the irrigated
terraces of the Hunzas is small; ample soil aeration results from their
construction; the irrigation water brings annual additions of fine silt
produced by the neighbouring glacier; the very greatest care is taken to
return to the soil ail human, animal, and vegetable wastes after being
first composted together. Land is limited: upon the way it is looked
after life depends. A perfect agriculture, in which all the factors that
combine to produce high quality in food, naturally results.

What of the people who live upon this produce? In The WHEEL OF HEALTH,
Wrench has gathered together all the information available and has laid
stress on their marvellous agility and endurance, good temper and
cheerfulness. These men think nothing of covering the 60 miles to Gilgit
on foot in one stretch, doing their business and then returning.

There is one point about the Hunza agriculture which needs further
investigation. The staircase cultivation of these hillmen receives
annual dressings of fresh rock-powder, produced by the grinding effect
of the glacier ice on the rocks and carried to the fields in the
irrigation water. Is there any benefit conferred on the soil and on the
plant by these annual additions of finely divided materials? We do not
know the composition of this silt. If it contains finely divided
limestone its value is obvious. If it is made up for the most part of
crushed silicates, its possible significance awaits investigation. Do
the mineral residues in the soil need renewal as humus does? If so, then
Nature has provided us with an Experiment Station ready-made and with
results that cannot be neglected. Perhaps in the years to come, some
heaven-sent investigator of the Charles Darwin type will go thoroughly
into this Hunza question on the spot, and will set out clearly all the
factors on which their agriculture and their marvellous health depend.

A study of the races of India and of their diet, coupled with the
experimental work on rats carried out by McCarrison, leaves no doubt
that the greatest single factor in the production of good health is the
right kind of food and the greatest single factor in the production of
bad health is the wrong kind of food. Further, the very remarkable
health and physique enjoyed by the Hunza hillmen appears to be due to
the efficiency of their ancient system of farming.

These results suggest that the population of Great Britain should be
studied and the efficiency of our food supply investigated. If the
physique and health of a nation ultimately depend on the fresh produce
of well-farmed land, if bad farming is a factor in the production of
poor physique and bad health, we must set about improving our
agriculture without delay.

Two very different methods have recently been employed for testing the
efficiency of the food supply of this country. In the first case
(Cheshire) the population of a whole county, which includes both rural
and urban areas, has been studied in the mass for a period of
twenty-five years and the general results have been recorded. In the
second case (Peckham) a number of families have been periodically
examined with a view to throwing light on the general health and
efficiency of a group of comparatively well-to-do workers in a city like
London.

The methods adopted in the study of the population of Cheshire and in
the publication of the results are highly original. About twenty-five
years ago, the National Health Insurance Act for the Prevention and Cure
of Sickness came into force. This measure has brought the population
under close medical observation for a quarter of a century. If the
experience of the Panel and family doctors of the county could be
synthesized, valuable information as to the general health of the
community would be available. This has been accomplished. The local
Medical and Panel Committee of Cheshire, which is in touch with the 600
family doctors of the county, has recorded its experience in the form of
a Medical Testament. They find it possible to report definite progress
in the 'Cure of Sickness'--the second part of the objective framed by
the National Health Insurance Act. There is no doubt that we have learnt
to 'postpone the event of death' and this is the more remarkable in view
of the rise in sickness, in short the failure of the first part of the
Act's objective. On this latter count there is no room for complacency.

'Our daily work brings us repeatedly to the same point--this illness
results from a life-time of wrong nutrition.' They then examine the
consequences of wrong nutrition under four heads--bad teeth, rickets,
anaemia, and constipation--and indicate how all this and much other
trouble can be prevented by right feeding. For example, in dealing with
the bad teeth of English children some striking facts are emphasized. In
1936 out of 3,463,948 schoolchildren examined, no less than 2,425,299
needed dental treatment. That this reproach can be removed has been
shown by Tristan da Cunha, where the population is fed on the fresh
produce of sea and soil--fish, potatoes, and seabirds' eggs are the
staple diet with sufficient milk and butter, meat occasionally and some
vegetables--all raised naturally without the help of artificial manures
and poison sprays. In 1932, 156 persons examined had 3,181 permanent
teeth of which 74 were carious. Imported flour and sugar have been
brought in to a greater extent of late, which may account for the
tendency of the teeth to deteriorate observed in 1937.

The Testament then goes on to the work of McCarrison (referred to above)
'whose experiments afford convincing proof of the effects of food and
guidance in the application of the knowledge acquired'. This has been
applied in local practice in Cheshire and the results have been amazing.
Two examples will suffice.

1. In a Cheshire village the nutrition of expectant mothers is
supervised by the local doctor once a month. The food of the mother is
whole-meal bread, raw milk, butter, Cheshire cheese, oatmeal porridge,
eggs, broth, salads in abundance, green leaf vegetables, liver and fish
weekly, fruit in abundance and a little meat. The whole-meal bread is
made from a mixture of two parts locally grown wheat, pulverized by a
steel fan revolving 2,500 times a minute, and one part of raw wheat-germ
(fresh off the rollers of a Liverpool mill). The flour is baked within
thirty-six hours at most--a point to be rigidly insisted upon--and a
rather close but very palatable bread is obtained. With rare exceptions
the mothers feed their infants at the breast--nine months is advised and
then very slow weaning finishing at about a year. The nursing mother's
food continues as in pregnancy; the infants are fed five times a day
with four-hour intervals beginning at 6 a.m. The children are splendid;
perfect sets of teeth are now more common; they sleep well; pulmonary
diseases are almost unknown; one of their most striking features is
their good humour and happiness. They are sturdy-limbed, beautifully
skinned, normal children. This was not a scientific experiment. It was
part of the work of family practice. The human material was entirely
unselected and the food was not specially grown; but that, in spite of
these imperfections, the practical application of McCarrison's work
should yield recognizable results shows that in a single generation
improvement of the race can be achieved.

2. A young Irishman aged 23, with a physique and an alertness of mind
and body it was a delight to behold, was found to be suffering from
catarrhal jaundice after two months' residence in England, where he had
been living on a diet mostly composed of bacon, white bread, meat
sandwiches and tea, with a little meat and an occasional egg. In Ireland
his food had consisted of the fresh natural products of the
soil--potatoes, porridge, milk and milk products, broth (made from
vegetables) and occasional meat, eggs, and fish. The change over to a
diet of white bread and sophisticated food was at once followed by
disease. This case shows how quickly good health can be lost by improper
feeding.

The Testament then leaves the purely medical domain and deals with that
principle or quality in the varied diets which produces the same
result--health and freedom from disease (such as the Esqulmaux on flesh,
liver, blubber, and fish; the Hunzas and Sikhs on wheaten chappattis,
fruit, milk, sprouted legumes and a little meat; the islanders of
Tristan on potatoes, seabirds' eggs, fish, and cabbage). In all these
cases the diets have one thing in common--the food is fresh and little
altered by preparation. The harvest of the sea is a natural product.
When the foods are based on agriculture, the natural cycle from soil to
plant, animal and man is complete without the intervention of any
chemical or substitution phase. In other words, when the natural produce
of sea and soil has escaped the attention of agricultural science and
the various food preservation processes, it would seem that health
results and that there is a marked absence of disease.

The last part of the Medical Testament deals with my own work on the
connexion between a fertile soil and healthy plants and animals; with
the means by which soil fertility can be restored and maintained; with a
number of examples in which this has been done. These have already been
described and need not be repeated.

This remarkable document concludes with the following words:


'The better manuring of the home land so as to bring an ample succession
of fresh food crops to the tables of our people, the arrest of the
present exhaustion of the soil and the restoration and permanent
maintenance of its fertility concern us very closely. For nutrition and
the quality of food are the paramount factors in fitness. No health
campaign can succeed unless the materials of which the bodies are built
are sound. At present they are not.

'Probably hall our work is wasted' since our patients are so fed from
the cradle, indeed before the cradle, that they are certain
contributions to a C3 nation. Even our country people share the white
bread, tinned salmon, dried milk regime. Against this the efforts of the
doctor resemble those of Sisiphus.

'This is our medical testament, given to all whom may concern--and whom
does it not concern?'


The Testament was put to a public meeting held at Crewe on March 22nd,
1939, by the Lord Lieutenant of Cheshire, Sir William
Bromley-Davenport, and carried by a unanimous vote. More than five
hundred persons representing the activities of the County of Cheshire
were present. The Medical Testament was published in full in the issue
of the British Medical Journal of April 15th, 1939. It has been widely
noticed in the press all over the Empire.

The experience of the Cheshire doctors is supported by the work of
Doctors Williamson and Pearse at the Peckham Health Centre in South
London. In connexion with the study of families whose average wage is
between 3 pounds 15s. and 4 pounds 10s. a week, about 20,000 medical
examinations have been recorded. The results have recently been published
in book form under the title BIOLOGISTS IN SEARCH OF MATERIAL
(Faber & Faber). It was found that no less than 83 per cent. of apparently
normal people had something the matter with them, ranging from some minor
maladjustment to incipient disease. One of the most important
contributions of these Peckham pioneers has been to unearth the
beginnings of a C3 population. The next step will be to see how far
these early symptoms of trouble can be removed by fresh food grown on
fertile soil. For this the Centre must have: (1) a large area of land of
its own on which vegetables, milk, and meat can be raised, and (2) a
mill and bakehouse in which whole-meal bread, produced on Cheshire lines
from English wheat grown on fertile soil, can be prepared. In this way a
large amount of food resembling that of the Hunza hillmen can be
obtained. The medical records of the families which consume this
produce, after the change over from the canned stuffof the shops and the
semi-carrion of the cold stores has been made, will form interesting
reading.

The health of our population has been studied by these two very
different methods. Both lead to the same conclusion, namely, that all is
not well: that there is an enormous amount of indisposition,
inefficiency, and actual disease. The Medical Testament boldly suggests
that want of freshness in the food and improper methods of agriculture
are at the root of the mischief. This provides a stimulating hypothesis
for future work. A case for action has been established. The basis of
the public health system of the future has been foreshadowed.

A certain amount of supporting evidence is already available. Two recent
examples can be quoted, the first dealing with live stock, the second
with schoolboys.

At Marden Park in Surrey, Sir Bernard Greenwell has found that a change
over to a ration of fresh home-grown food (raised on soil manured with
humus) fed to poultry and pigs has been followed by three important
results: (1) the infantile mortality has to all intents and purposes
disappeared; (2) the general health and well-being of the live stock has
markedly improved; (3) a reduction of about lo per cent. in the ration
has been obtained because such home-grown produce possesses an
extra-satisfying power.

At a large preparatory school near London, at which both boarders and
day-boys are educated, the change over from vegetables, grown with
artificial manures, to produce grown on the same land with Indore
compost has been accompanied by results of considerable interest to
parents and to the medical profession. Formerly, in the days when
artificials were used, cases of colds, measles, and scarlet fever used
to run through the school. Now they tend to be confined to the single
case imported from outside. Further, the taste and quality of the
vegetables have definitely improved since they were raised with humus.

Much more work on these lines is needed. A search will have to be made
throughout Great Britain and Northern Ireland for resident communities
such as boarding-schools, training centres, the resident staff of
hospitals and convalescent homes which satisfy the following four
conditions: (1) the control of sufficient fertile and well-farmed land
for growing the vegetables, fruit, milk and milk products, and meat
required by the residents; (2) a mill and bakehouse for producing
wholemeal bread with the new Cambridge wheats grown on fertile soil
without the assistance of artificial manures; (3) the medical
supervision of the community by a carefully chosen disciple of
preventive medicine; (4) a man or woman in control who is keenly
interested in putting the findings of the Medical Testament to the test
and who is prepared to surmount any difficulties that may arise. In a
very few years it is more than probable that islands of health will
arise in an ocean of indisposition. No controls will be necessary--these
will be provided by the country-side round about. Elaborate statistics
will be superfluous as the improved health of these communities will
speak for itself and will need no support from numbers, tables, curves,
and the higher mathematics. Mother earth in the appearance of her
children will provide all that is necessary. The materials for Medical
Testament No. 2 will then be available. Cheshire no doubt will again
take the lead and provide a second milestone on the long road which must
be traversed before this earth can be made ready to receive her
children.

In this work research can assist. Medical investigations should be
deflected from the sterile desert of disease to the study of health--to
mankind in relation to his environment. Agricultural search, after
reorganization on the lines suggested in the next chapter, should start
afresh from a new base-line--soil fertility--and so provide the raw
material for the nutritional studies of the future--fresh produce from
fertile soil. The agricultural colleges with their farms should devote
some of their resources to feeding themselves, and so demonstrating what
the products of well-farmed land can accomplish. They should strive to
equal and then to surpass what a tribe of northern India has already
achieved.



BIBLIOGRAPHY

SCOTT WILLIAMSON, G., and INNES PEARSE, H. Biologists in Search of
Material, Faber & Faber, London, 1938.

HOWARD, SIR ALBERT. 'Medical Testament on Nutrition', British Medical
Journal, May 27th, 1939, p. 1106.

MCCARRISON, SIR ROBERT. 'Nutrition and National Health' (Cantor Lectures),
Journal of the Royal Society of Arts, lxxxiv, 1936, pp. 1047, 1067,
and 1087.

-------'Medical Testament on Nutrition', Supplement to the British
Medical Journal, April 15th, 1939, p. 157; Supplement to the New English
Weekly, April 6th, 1939.

WRENCH, G. T. The Wheel of Health, London, 1938.





PART IV  AGRICULTURAL RESEARCH




CHAPTER XIII



A CRITICISM OF PRESENT-DAY AGRICULTURAL RESEARCH


A want of relation between the conventional methods of investigation and
the nature of disease in plants and animals has been shown to exist. The
vast fabric of agricultural research must now be examined in order to
determine whether effective contact has been maintained with the
problems of farming. This is the theme of the present chapter.

The application of science to agriculture is a comparatively modern
development, which began in 1834 when Boussingault laid the foundations
of agricultural chemistry. Previously all the improvements in farming
practice resulted from the labours of a few exceptional men, whose
innovations were afterwards copied by their neighbours. Progress took
place by imitation. After 1834 the scientific investigator became a
factor in discovery. The first notable advance by this new agency
occurred in 1840, when Liebig's classical monograph on agricultural
chemistry appeared. This at once attracted the attention of
agriculturists. Liebig was a great personality, an investigator of
genius endowed with imagination, initiative, and leadership and was
exceptionally well qualified for the scientific side of his task--the
application of chemistry to agriculture. He soon discovered two
important things: (1) that the ashes of plants gave useful information
as to the requirements of crops, and (2) that a watery extract of humus
gave little or no residue on evaporation. As the carbon of the plant was
obtained from the atmosphere by assimilation in the green leaf,
everything seemed to point to the supreme importance of the soil and the
soil solution in the raising of crops. It was only necessary to analyse
the ashes of plants, then the soil, and to apply to the latter the
necessary salts to obtain full crops. To establish the new point of view
the humus theory, which then held the field, had to be demolished.
According to this theory the plant fed on humus. Liebig believed he had
shown that this view was untenable; humus was insoluble in water and
therefore could not influence the soil solution.

In all this he followed the science of the moment. In his onslaught on
the humus theory he was so sure of his ground that he did not call in
Nature to verify his conclusions. It did not occur to him that while the
humus theory, as then expressed, might be wrong, humus itself might be
right. Like so many of his disciples in the years to come, he failed to
attach importance to the fact that the surface soil always contains very
active humus, and did not perceive that critical field experiments,
designed to find out if chemical manures were sufficient to supply all
the needs of crops, should always be done on the sub-soil, after
removing the top 9 inches or so. If this is not arranged for, the yield
of any crop may be influenced by the humus already in the soil. Failure
to perceive this obvious fact is the main reason why Liebig and his
disciples went astray.

He also failed to realize the supreme importance to the investigator of
a first-hand knowledge of practical-agriculture, and the significance of
the past experience of the tillers of the soil. He was only qualified
for his task on the scientific side; he was no farmer; as an
investigator of the ancient art of agriculture he was only half a man.
He was unable to visualize his problem from two very different points of
view at one and the same moment--the scientific and the practical. His
failure has cast its shadow on much of the scientific investigation of
the next hundred years. Rothamsted, which started in 1843, was
profoundly influenced by the Liebig tradition. The celebrated
experiments on Broadbalk Field caught the fancy of the farming world.
They were so telling, so systematic, so spectacular that they set the
fashion till the end of the last century, when the great era of
agricultural chemistry began to wane. During this period (1840-1900),
agricultural science was a branch of chemistry; the use of artificial
manures became firmly welded into the work and outlook of the Experiment
Stations; the great importance of nitrogen (N), phosphorus (P), and
potash (K) in the soil solution was established; what may briefly be
described as the NPK mentality was born.

The trials of chemical manures, however, brought the investigators from
the laboratory to the land; they came into frequent contact with
practice; their outlook and experience gradually widened. One result was
the discovery of the limitations of chemical science; the deficiencies
of the soil, suggested by chemical analysis, were not always made up by
the addition of the appropriate artificial manure; the problems of crop
production could not be dealt with by chemistry alone. The physical
texture of the soil began to be considered; the pioneering work of
Hilgard and King in America led to the development of a new branch of
the subject--soil physics--which is still being explored. Pasteur's work
on fermentation and allied subjects, by drawing attention to the fact
that the soil is inhabited by bacteria and other forms of life,
disclosed a new world. A notable elucidation of the complex life of the
soil was contributed by Charles Darwin's fascinating account of the
earthworm. The organisms concerned with the nitrification of organic
matter were discovered by Winogradsky and the conditions necessary for
their activity in pure cultures were determined. Another branch of
agricultural science--soil bacteriology--arose. While the biology and
physics of the soil were being studied, a new school of soil science
arose in Russia. Soils began to be regarded as independent natural
growths: to have form and structure due to climate, vegetation, and
geological origin. Systems of soil classification, based primarily on
the soil profile, with an appropriate nomenclature developed in harmony
with these views, which, for the moment, have been widely accepted. A
new branch of soil science--pedology--arose. The Liebig conception of
soil fertility was thus gradually enlarged and it became clear that the
problem of increasing the produce of the soil did not lie within the
domain of any one science but embraced at least four--chemistry,
physics, bacteriology, and geology.

At the beginning of the present century, the investigators began to pay
more attention to what is after all the chief agent in crop
production--the plant itself. The rediscovery of Mendel's law by
Correns, the conception of the unit species which followed the work of
Johannsen and the recognition of its importance in improvement by
selection have led directly to the modern studies of cultivated crops,
in which the Russians have made such noteworthy contributions. The whole
world is now being ransacked to provide the plant breeders with a wide
range of raw material. These botanical investigations are constantly
broadening and now embrace the root system, its relation to the soil
type, the resistance of the plant to disease, as well as the internal
mechanism by which inheritance takes place. The practical results of the
last forty years which have followed the application of botanical
science to agriculture are very considerable. In wheat, for example, the
labours of Saunders in Canada led to the production of Marquis, an early
variety with short straw, which soon covered 20,000,000 acres in Canada
and the neighbouring States of the Union. This is the most successful
wheat-hybrid yet produced. In Australia the new wheats raised by Farrer
were soon widely cultivated. In England the new hybrids raised at
Cambridge established themselves in the wheat-growing areas of this
country. In India the Pusa wheats covered several million acres of land.
By 1915 the total area of the new varieties of wheat had reached over
25,000,000 acres. When the annual dividend, in the form of increased
wealth, was compared with the capital invested in these investigations,
it was at once evident that the return was many times greater than that
yielded by the most successful industrial enterprise. Similar results
have been obtained with other crops. The new varieties of malting
barley, raised by Beaven, have for years been a feature of the English
country-side; the new varieties of sugarcane produced by Barber at
Coimbatore in South India soon replaced the indigenous types of cane in
northern India. In cotton, jute, rice, grasses, and clovers and many
other crops new varieties have been obtained; the old varieties are
being systematically replaced. Nevertheless the gain per acre obtained
by changing the variety is as a rule small. As will be seen in the next
chapter, the great problem of agriculture at the moment is the intensive
cultivation of these new types; how best to arrange a marriage between
the new variety and a fertile soil. Unless this is done, the value of a
new variety can only be transient; the increased yield will be obtained
at the expense of the soil capital; the labours of the plant breeders
will have provided another boomerang.

A number of other developments have taken place which must briefly be
mentioned. Since the Great War the factories then engaged in the
fixation of atmospheric nitrogen for the manufacture of the vast
quantities of explosives, needed to defend and to destroy armies well
entrenched, have had to find a new market This was provided by the large
area of land impoverished by the over-cropping of the war period. A
demand was created by the low price at which the mass-produced unit of
nitrogen could be put on the market and by the reliability of the
product. Phosphates and potash fell into line Ingenious mixtures of
artificial manures, containing everything supposed to be needed by the
various crops, could be purchased all over the world. Sales increased
rapidly; the majority of farmers and market gardeners soon based their
manurial programme on the cheapest forms of nitrogen, phosphorus, and
potash or on the cheapest mixtures. During the last twenty years the
progress of the artificial manure industry has been phenomenal; the age
of the manure bag has arrived; the Liebig tradition returned in full
force.

The testing of artificial manures and new varieties has necessitated
innumerable field experiments, the published results of which are
bewildering in their volume, their diversity, and often in the
conclusions to be drawn from them. By a judicious selection of this
material, it is possible to prove or disprove anything or everything.
Something was obviously needed to regulate the torrent of field results
and to ensure a greater measure of reliability. This was attempted by
the help of mathematics. The technique was overhauled; the field plots
were 'replicated' and 'randomized'; the figures were subjected to a
rigid statistical scrutiny. Only those results which are fortunate
enough to secure what has been described as the fastidious approval of
the higher mathematics are now accepted. There is an obvious weakness in
the technique of these field experiments which must be mentioned. Small
plots and farms are very different things. It is impossible to manage a
small plot as a self-contained unit in the same way as a good farm is
conducted. The essential relation between live stock and the land is
lost; there are no means of maintaining the fertility of the soil by
suitable rotations as is the rule in good farming. The plot and the farm
are obviously out of relation; the plot does not even represent the
field in which it occurs. A collection of field plots cannot represent
the agricultural problem they set out to investigate. It follows that
any findings based on the behaviour of these small fragments of
artificially manured land are unlikely to apply to agriculture. What
possible advantage therefore can be obtained by the application of the
higher mathematics to a technique which is so fundamentally unsound?

With the introduction of artificials there has been a continuous
increase in disease, both in crops and in live stock. This subject has
already been discussed. It is mentioned again to remind the reader of
the vast volume of research on this topic completed and in progress.

Side by side with the intrusion of mathematics into agriculture, another
branch of the subject has grown up--economics. The need for reducing
expenditure so that farming could yield a profit has brought every
operation, including manuring and the treatment of disease, under
examination in order to ascertain the cost and what profit, if any,
results. Costings are everywhere the rule; the value of any experiment
and innovation is largely determined by the amount of profit which can
be wrung from Mother earth. The output of the farm and of the factory
have been looked at from the same standpoint--dividends. Agriculture
joined the ranks of industry.

Agricultural science, like Topsy, has indeed grown. In little more than
forty years a vast system of research institutes, experimental farms,
and district organizations (for bringing the results of research to the
farming community) has been created all over the world. As this research
structure has grown up in piecemeal fashion as a result of the work of
the pioneers, it will be interesting to examine it and to ascertain
whether or not direction has been maintained. Has the present
organization any virtue in itself or does it merely crystallize the
stages reached in the scientific exploration of a vast biological
complex? If it is useful it will be justified by results; if its value
is merely historical, its reform can only be a question of time.

In Great Britain two documentas have recently appeared (Constitution and
Functions of the Agricultural Research Council, H.M. Stationery Office
London, 1938; Report on Agricultural Research in Great Britain, PEP., 16
Queen Anne's Gate, London, S.W. 1, 1938.) which make it easy to conduct
an inquest on agricultural research in this country. They describe fully
the structure and working of the offficial machine which controls and
finances research, the organization of the work itself, and the methods
of making the results known to farmers. In addition to the Treasury and
the Committee of the Privy Council, official control is exercised by no
less than three other organizations: (1) The Ministry of Agriculture
(which administers the grants); (2) the Development Commission (which
awards funds from grants placed at its disposal by the Treasury); and
(3) the Agricultural Research Council (which reviews and advises on
applications for grants, and also coordinates State-aided agricultural
research in Great Britain). Eventually the Research Institutes, which
carry out the work, are reached.

These Research Institutes are fifty in number and are of three types:

(a) Government laboratories or research stations;

(b) Institutes attached to universities or university colleges;

(c) Independent institutes.

Most of these institutes were set up in 1911 to provide for basic
research in each of the agricultural sciences: agricultural economics,
soil science, plant physiology, plant breeding, horticulture and fruit
research, plant pathology, animal heredity and genetics, animal
physiology and nutrition, animal diseases, dairy research, food
preservation and transport, agricultural engineering and agricultural
meteorology. These groups can again be divided into four classes:
background research (dealing with fundamental scientific principles);
basic research (the recognized sphere of the research institute); ad hoc
research (the study of specific practical problems, as they arise, such
as the control of foot-and-mouth disease); pilot or development research
(such as the growing on of new strains of plants).

After research proper, the organization then deals with the results of
its investigations. The first stage in this process is the Provincial
Advisory Service which operates in sixteen provinces. From one to seven
Advisory Officers are stationed at each centre, their specialized
knowledge being at the disposal of County Organizers and farmers. The
final link in the long chain from the Treasury to the soil is provided
by the Agricultural Organizers of the County Councils, who act as a free
Scientific Information Bureau for farmers and market gardeners. Most
counties also support farm institutes-which provide technical education
and also have experimental farms of their own. Appended to this research
structure are two Imperial Institutes and nine Imperial Bureaux, which
provide an information and abstracting service in entomology, mycology,
soil science, animal health, animal nutrition and genetics, plant
genetics, fruit production, agricultural parasitology, and dairying. The
number of agricultural research workers in Great Britain is about 1,000.
The total State expenditure on agricultural research amounted in 1938 to
about 700,000 pounds. This is about 90 per cent. of the total cost, the
remaining 10 per cent. being met by local authorities, universities,
marketing boards, private companies and individuals, agricultural
societies, fees, and sales of produce. The farmers, even when organized
as marketing boards, have shown little recognition of the value of
research and make no serious contribution to its cost.

A formidable, complex, and costly organization has thus grown up since
1911. No less than seven organs of the Central Government have to do
with agricultural research, the personnel of which has to be fed with a
constant stream of reports, memoranda, and information which must absorb
a large amount of the time and energy of the men who really matter--the
investigators. A feature of the official control is the committee, a
device which has developed almost beyond belief since the Agricultural
Research Council came into being in 1934. Six standing committees were
first formed to carry out a survey of existing research. These led to a
crop of new committees to go farther into matters disclosed by this
preliminary survey. In addition to the six standing committees, no less
than fifteen scientific committees are dealing with the most important
branches of research. Twelve of these fifteen committees are considering
the diseases of crops and live stock--the main preoccupation of the
Council at the present time.

Is so much machinery necessary? Between the Treasury (which decides what
sum can be granted) and the Research Institutes, would not a single
agency such as the Ministry of Agriculture be all that is needed in the
way of control? This would appear likely when it is remembered that
there is one thing only in research that matters--the man or woman who
is to undertake it. Once these are found and provided with the means,
nothing else is necessary. The best service the official organization
can then perform is to remain in the background, ready to help when the
workers need assistance. It follows then that simplicity and modesty
must always be the keynote of the controlling authority.

A serious defect in the research organization proper is encountered at
the very beginning. The Research Institutes are organized on the basis
of the particular science, not on recognized branches of farming. The
instrument (science) and the subject (agriculture) at once lose contact.
The workers in these institutes confine themselves to some aspect of
their specialized field; the investigations soon become
departmentalized; the steadying influence of firsthand practical
experience is the exception rather than the rule. The reports of these
Research Institutes describe the activities of large numbers of workers
all busy on the periphery of the subject and all intent on learning more
and more about less and less. Looked at in the mass, the most striking
feature of these institutions is the fragmentation of the subject into
minute units. It is true that attempts are made to co-ordinate this
effort by such devices as the formation of groups and teams, but as will
be shown later this rarely succeeds. Another disquieting feature is the
gap between science and practice. It is true that most, if not all, of
these establishments possess a farm, but this is mostly taken up with
sets of permanent experiments. I know of no research institute in Great
Britain besides Aberystwyth where a scientific worker has under his
personal control an area of land with his own staff where he can follow
the gleam wheresoever it may lead him. Even Aberystwyth stops short
before the animal is reached. The improved strains of herbage plants and
the method of growing them are not followed to their logical
conclusion--a flock of healthy sheep ready for the market and a supply
of well-nourished animals by which the breed can be continued.

Has the official machine ever posed to itself such questions as these?
What would be the reaction of some Charles Darwin or Louis Pasteur of
the future to one or other of these institutes? What would have been
their fate if circumstances had compelled them to remain in such an
organization, working at some fragment of science? How can the excessive
departmentalization of research provide that freedom without which no
progress has ever been made in science? Is it rational in such a subject
as agriculture to attempt to separate science and practice? Will not the
organization of such research always be a contradiction in terms,
because the investigator is born not made? The official reply to these
questions would form interesting reading.

How does this research organization strike the tillers of the soil for
whose benefit it has been created? The farmers complain that the
research workers are out of touch with farming needs and conditions;
that the results of research are buried in learned periodicals and
expressed in unintelligible language; that these papers deal with
fragments of the subject chosen haphazard; that the organization of
research. is so cumbersome that the average farmer cannot obtain a
prompt answer to an inquiry and that there are no demonstration farms at
which practical solutions of local problems are to be seen.

There seems to be only one effective answer to these objections. The
experiment station workers should take their own advice and try out
their results. The fruits of this research should be forthcoming on the
land itself. All the world over this simple method of publication never
fails to secure the respect and attention of the farming community;
their response to such messages is always generous and immediate. In
Great Britain, however, the retort of the administration takes another
line. The idea is fostered that the experiment stations are arsenals of
scientific knowledge which actually needs explanation and dilution for
the farmer and his land to benefit. Thus in dealing with this point the
PEP Report states: 'One of the principal tasks of the administrator is
to ensure that the general body of scientific knowledge, including
recent results of the research workers' efforts, is brought to the
farmer in such a way that he can understand it and apply it on his
farm.' The most effective way of doing this is for the organization to
demonstrate, in a practical way for all to see, the value of some, at
any rate, of these researches. This simple remedy will silence the
critics and scoffers; any delay in furnishing it will only add fuel to
the fire. After all, a research organization which costs the nation
700,000 pounds a year cannot afford to have its operations called in
question by the very men for whose benefit it has been designed. The
complaints of the farming community must be removed.

A system not unlike that just described in Great Britain has been
adopted in the Empire generally. There is, however, one interesting
difference. The official machinery is comparatively simple; the
multiplication of agencies and supervisory committees is not so
pronounced; the step from the Treasury to the farmer is much shorter.
When, however, we come to the research proper, the system is very
similar to that which obtains in Great Britain. There is the same
tendency to divide research into two groups--fundamental and local; to
rely on the piecing together of fragments of science; to extol the
advantages of co-operation; to adopt the team rather than the
individual. It is the exception rather than the rule to find an
investigation in the hands of one competent investigator, provided with
land, ample means, and complete freedom.

The completion of an imperial chain of experiment stations for
fundamental research was emphasized by a Conference (Report of the
Imperial Agricultural Research Conference, H.M. Stationery Office,
London, 1927) which met in London in 1927. The financial depression,
which set in soon after the Report appeared, interfered with this
scheme. No additions to the two original links of the chain of five or
six super-Research Institutes contemplated--sometimes irreverently
referred to as the 'chain of pearls'--have been added to the one in the
West Indies (Trinidad) and the other in East Africa (Amani).

Two examples will suffice to illustrate the methods now being employed
in this fundamental research work. These are taken from a recent paper
by Sir Geoffrey Evans, C.I.E., entitled 'Research and Training in
Tropical Agriculture', which appeared in the Journal of the Royal
Society of Arts of February 10th, 1939. Sir Geoffrey selected the
current work on cacao and bananas when explaining how research is
conducted at the Imperial College of Tropical Agriculture in Trinidad.
He laid great stress on the merits of team work, a method of
investigation which we must now examine. These Trinidad examples of
research do not stand alone. They resemble what is going on all over the
Empire, including India. Similar work can be collected by the basketful.

In 1930 a study of cacao was commenced in Trinidad in two
directions--botanical and chemical. After a preliminary examination of
the crop, which is made up of a bewildering number of types, varying
widely in fruitfulness and quality, a hundred special trees were
selected as a basis for improvement. As cacao does not breed true from
seed, methods of vegetative reproduction by means of cuttings and bud
wood were first studied. The mechanism of pollination, however, showed
that cacao is frequently self-sterile and that many of the special trees
required to be cross-pollinated before they could set seed. Suitable
pollen parents had then to be found. Manurial experiments on
conventional lines led to numerous field experiments all over the island
as well as to a detailed soil survey. The biochemical study of the cacao
bean produced results described as intricate and baffling; no
correlation between the tannin content and quality emerged. The
Economics Department of the College investigated the decline of the
industry since the War, and established the interesting fact that a
cacao plantation reaches its peak in about twenty-five years and then
begins to decline. The causes of this decline have been studied and the
system of regenerating old plantations by supplying vacancies with
high-yielding types has been devised. As, however, the decline of these
cacao estates is more likely to be due to wornout soil than anything
else, this method by itself is not likely to succeed. Pests and diseases
take their toll of cacao, so the entomologists and mycologists were
called in to deal with thrips--the most serious insect pest--and the
witch-broom disease--a fungous pest which has done great damage in the
West Indies.

The Trinidad investigations on the banana owe their origin to the
outbreak of the Panama disease (Fusarium cubense) all over the West
Indies and the Central American Republics. When the nature of the
trouble was established by the mycologists, a search for immune and
resistant varieties followed. This included plant breeding, the
investigation of the causes of seedlessness, the raising of numerous
seedlings, and the search for the ideal parent from which to breed a new
commercial banana which is disease-resistant, seedless, of good quality,
and capable of standing up to transport conditions. In this work the
assistance Or the Royal Botanic Gardens at Kew was enlisted; it involved
the problem of protecting the banana in the West Indies from disease,
including virus, when importing from Malaya (the home of the chief
banana of commerce--the Gros Michel) and other places the material
needed for the plant-breeding work. The problems of ripening during
transport, including a study of the respiration processes during gas
storage and the effect of humidity, and the reason for chilling also
received attention.

These interesting investigations, which have as their aim the production
of higher yields of better cacao and better bananas, have been carried
on by what is known as team work. They have necessitated the services of
botanists, chemists, mycologists, entomologists and economists, and both
have involved considerable expense and much time.

As examples of the way in which the more difficult problems of tropical
agriculture are now approached by a number of workers, they are typical
of the methods of research everywhere. Many aspects of the cacao and
banana problems have been studied; the methods of research have been
clearly set out. The workers have evidently spared no pains to achieve
success. Nevertheless, the results are negative. The paper under review
suggests that matters are still very much in the programme stage; few if
any tangible results have been obtained; neither the cacao nor the
banana industry has been set on its feet.

If we take a wide view of these two problems and consider: (1) the
present methods by which cacao and bananas are grown in the West Indies;
(2) the indications furnished by disease that all is not well with these
plantations, and (3) the best examples of cacao and banana cultivation
to be found in the East where, by means of farm-yard manure only, heavy
crops of fine, healthy produce are obtained, the suspicion grows that at
least some vital factors have been forgotten in these Trnidad
investigations. The spectacular response of cacao trees to humus seems
to have been missed altogether and no attention has been given to the
significance of the mycorrhizal association in the roots of both cacao
trees and bananas. In the cacao and banana plantations in the West
Indies, there is a want of balance between the crop and the animal.
There is insufficient live stock. There is a disquieting amount of
disease and general unthriftiness, which is associated with the absence
of conditions suitable for mycorrhizal formation.

Practical experience of the best banana and cacao cultivation in India
and Ceylon proves beyond all doubt that the two factors which are
essential, if satisfactory yields of high quality are to be obtained and
the plantations are to be kept healthy, are: (1) good soil aeration, and
(2) supplies of freshly prepared humus from animal and vegetable wastes,
which are needed to maintain in effective operation the mycorrhizal
association. Want of attention to either of these factors is at once
followed by loss of quality, by diminished returns, and finally by
disease. A better way of dealing with these West Indian problems would
have been by good farming methods, including a proper balance between
crops and live stock, and by the conversion of all available vegetable
and animal wastes into humus.

The Trinidad investigations are quoted as 'an example which can hardly
fail to impress the student investigator with the necessity for
co-operation'. In reality all they show is how employment can be found
for a number of specialists for quite a long time, and indeed what a lot
of scientific work can be done by competent workers with purely negative
results as far as the yield and the quality of the crop are concerned.

It is not difficult to see the weakness of this method of approach. The
problem is never envisaged as a whole and studied in the field from
every angle before research on some branch of science is undertaken.
Methods of crop improvement are now expected to come from the laboratory
and not from the field as they have always done throughout farming
history. The control of the team is of necessity very loose. It is
normally placed in the hands of persons of administrative rather than
practical experience and of limited training in research methods. Often
they have other important duties and cannot give the time and thought
required. Unable themselves to make a correct diagnosis of the case in
the field, their only resource is to go on adding specialist after
specialist to their staff in the hope that the study of a fresh fragment
of the subject will lead them to some solution. It is almost certain
that had the West Indian problems been tackled by one investigator with
a real knowledge of farming combined with a wide training in science,
and had he been provided with the necessary land, money, and facilities
and with complete freedom in conducting the investigation, Sir Geoffrey
Evans would have told a very different story. From the point of view of
the students at the Trinidad College, it would have been still better to
have used these crops for illustrating both methods simultaneously--the
banana studied by a single investigator, adequately equipped; cacao by
means of a team. In this way the relative merits of the two methods
could have been settled for all time. In all probability, two results
would have been obtained: (1) the principle that the researcher is the
only thing that matters in research would have been established; (2)
team work would have ceased to be considered as an effective instrument
of investigation.

Team work offers no solution for the evils which result from
fragmentation of a research problem. The net woven by the team is often
full of holes. Is the fragmentation of the problem accompanied by any
other disadvantages? This question is at once answered if we examine any
of the major problems of presentday farming. Two British examples will
suffice to prove that an inevitable consequence of fragmentation and
specialization is loss of direction. Science then loses itself in a maze
of detail.

The retreat of the potato crop before blight, eelworm, and virus is one
of the most disquieting incidents in British agriculture. One of our
most important food crops cannot now be grown successfully on a field
scale without a thin film of copper salts; a new rotation of crops from
which the potato is omitted until the cysts of the eelworm disappear
from the soil; a frequent change of seed from Scotland, Wales, or
Northern Ireland. Evidently something is very wrong somewhere, because
this crop, when grown in thousands of fertile kitchen gardens throughout
the country, is healthy, not diseased. Agricultural science began by
fragmenting this potato problem into a number of parts. Potato blight
fell within the province of the mycologist; a group of investigators
dealt with eelworm; a special experiment station was created for virus
disease; the breeding and testing of disease resistant varieties was
again a separate branch of the work; the manuring and general agronomy
of the crop fell within the province of the agriculturist. The
multiplication of workers obscures rather than clarifies this wide
biological problem. The fact that these potato diseases exist at all
implies that some failure in soil management has occurred. The obvious
method of dealing with a collapse of this kind should have been to
ascertain the causes of failure rather than to tinker with the
consequences of some mistake in management. The net result has been that
all this work on the periphery of the subject has not solved the problem
of how to grow a healthy potato. This is because direction has been
completely lost.

The same story is repeated in manuring: fragmentation has again been
followed by loss of direction. Notwithstanding the fact that in the
forest Nature has provided examples to copy and in the peat-bog examples
to avoid, when devising any rational system of manuring, agricultural
science at once proceeded to fragment the subject. For nearly a hundred
years some of the ablest workers have devoted themselves to a study of
soil nutrients, including trace elements like boron, iron, and cobalt.
Green-manuring is a separate subject, so is the preparation of
artificial farm-yard manure and the study of the ordinary manure heap.
The weight of produce and the cost of manuring overshadow questions of
quality. The two subjects which really matter in manuring--the
preservation of soil fertility and the quality of the produce--escape
attention altogether, mainly because direction has been so largely lost.

The insistence on quantitative results is another of the weaknesses in
scientific investigation. It has profoundly influenced agricultural
research. In chemistry and physics, for example, accurate records are
everything: these subjects lend themselves to exact determinations which
can be recorded numerically. But the growing of crops and the raising of
live stock belong to biology, a domain where everything is alive and
which is poles asunder from chemistry and physics. Many of the things
that matter on the land, such as soil fertility, tilth, soil management,
the quality of produce, the bloom and health of animals, the general
management of live stock, the working relations between master and man,
the esprit de corps of the farm as a whole, cannot be weighed or
measured. Nevertheless their presence is everything: their absence
spells failure. Why, therefore, in a subject like this should there be
so much insistence on weights and measures and on the statistical
interpretation of figures? Are not the means (quantitative results and
statistical methods) and the subject investigated (the growth of a crop
or the raising of live stock) entirely out of relation the one to the
other? Can the operations of agriculture ever be carried out, even on an
experiment station, so that the investigator is sure that everything
possible has been done for the crop and for the animal? Can a mutually
interacting system, like the crop and the soil, for example, dependent
on a multitude of factors which are changing from week to week and year
to year, ever be made to yield quantitative results which correspond
with the precision of mathematics?

The invasion of economics into agricultural research naturally followed
the use of quantitative methods. It was an imitation of the successful
application of coatings to the operations of the factory and the general
store. In a factory making nails, for example, it is possible, indeed
eminently desirable, to compare the cost of the raw material and the
operations of manufacture, including labour, fuel, overhead expenses,
wear and tear and so forth, with the output, and to ascertain how and
where savings in cost and general speeding up can be achieved. Raw
materials, output, and stocks can all be accurately determined. In a
very short time a manufacturer with brains and energy will know the cost
of every step in the process to the fourth place of decimals. This is
because everything is computable. In a similar manner the operations of
the general store can be reduced to figures and squared paper. The men
in the counting-house can follow the least falling-off in efficiency and
in the winning of profit. How very natural it was some thirty years ago
to apply these principles to Mother earth and to the farmer! The result
has been a deluge of coatings and of agricultural economics largely
based on guess-work, because the machinery of the soil will always
remain a closed book. Mother earth does not keep a pass-book. Almost
every operation in agriculture adds or subtracts an unknown quantity to
or from the capital of the soil--fertility--another unknown quantity.
Any experimental result such as a crop is almost certain to be partly
due to the transfer of some of the soil's capital to the profit and loss
account of the farmer. The economics of such operations must therefore
be based on the purest of guess-work. The results can hardly be worth
the paper they are written on. The only things that matter on a farm are
these: the credit of the farmer--that is to say what other people,
including his labour force and his bank manager, think of him; the total
annual expenditure; the total annual income and the annual
valuation--the condition of the land and of the live and dead stock at
the end of the year. If all these things are satisfactory nothing else
matters. If they are not, no amount of coatings will avail. Why,
therefore, trouble about anything beyond these essentials?

But economics has done a much greater disservice to agriculture than the
collection of useless data. Farming has come to be looked at as if it
were a factory. Agriculture is regarded as a commercial enterprise; far
too much emphasis has been laid on profit. But the purpose of
agriculture is quite different from that of a factory. It has to provide
food in order that the race may flourish and persist. The best results
are obtained if the food is fresh and the soil is fertile. Quality is
more important than weight of produce. Farming is therefore a vital
matter for the population and ranks with the supply of drinking water,
fresh air, and protection from the weather. Our water supplies do not
always pay their way; the provision of green belts and open spaces does
not yield a profit; our housing schemes are frequently uneconomic. Why,
then, should the quality of the food on which still more depends than
water, oxygen, or warmth be looked at in a different way? The people
must be fed whatever happens. Why not, then, make a supreme effort to
see that they are properly fed? Why neglect the very foundation-stone of
our efficiency as a nation? The nation's food in the nature of things
must always take the first place. The financial system, after all, is
but a secondary matter. Economics therefore, in failing to insist on
these elementary truths, has been guilty of a grave error of judgement.

In allowing science to be used to wring the last ounce from the soil by
new varieties of crops, cheaper and more stimulating manures, deeper and
more thorough cultivating machines, hens which lay themselves to death,
and cows which perish in an ocean of milk, something more than a want of
judgement on the part of the organization is involved. Agricultural
research has been misused to make the farmer, not a better producer of
food, but a more expert bandit. He has been taught how to profiteer at
the expense of posterity--how to transfer capital in the shape of soil
fertility and the reserves of his live stock to his profit and loss
account. In business such practices end in bankruptcy; in agricultural
research they lead to temporary success. All goes well as long as the
soil can be made to yield a crop. But soil fertility does not last for
ever; eventually the land is worn out; real farming dies.

In the following chapter an example of the type of research needed in
the future will be described.



BIBLIOGRAPHY

CARREL, ALEXIS. Man, the Unknown, London, 1939.

Constitution and Functions of the Agricultural Research Council, H.M.
Stationery Office, London, 1938.

DAMPER, SIR WILLIAM C. 'Agricultural Research and the Work of the
Agricultural Research Council', Journal of the Farmers' Club, 1938, p. 55.

EVANS, SIR GEOFFREY. 'Research and Training in Tropical Agriculture',
Journal of the Royal Society of Arts, lxxxvii, 1939, p. 332.

LIEBIG, J. Chemistry in its Applications to Agriculture and Physiology,
London, 1840.

Report of the Imperial Agricultural Research Conference, H.M. Stationery
Office, London, 1927.

Report on Agricultural Research in Great Britain, PEP, 16 Oueen
Anne's Gate, London, 1938.




CHAPTER XIV



A SUCCESSFUL EXAMPLE OF AGRICULTURAL RESEARCH


In the last chapter the agricultural research of to-day was severely
criticized; its many shortcomings were frankly set out; suggestions were
made for its gradual amendment. That these strictures are justified will
be evident if we examine in detail a piece of successful research
carried out on the sugar-cane crop in India during a period of nearly
twenty-seven years: 1908-35.

In 1910 the investigations on sugar-cane in Northern India were mainly
concentrated in the United Provinces, where a considerable local
industry was already in existence. Narrow-leaved, thin canes were
planted under irrigation at the beginning of the hot season in March;
the crop was crushed by bullock power during the cold weather (January
to March); the juice was converted into crude sugar in open pans. The
yield was low, a little over one ton to the acre on the average. It was
decided to develop this primitive industry and the work, at first purely
chemical, was placed in the hands of Mr. George Clarke, the Agricultural
Chemist. The choice proved to be a happy one. Clarke combined a
first-class knowledge of chemistry and general science with considerable
experience of research methods, obtained under Professors Kipping and
Pope at Nottingham University College and the School of Technology,
Manchester. The son of a south Lincolnshire farmer, he had all his life
been familiar with good agricultural practice and had inherited a marked
aptitude for farming from a long line of yeomen ancestors. He had
therefore acquired the three preliminary qualifications essential for an
investigator in agriculture, namely, the makings of a good farmer, a
sound training in science, and a first-hand acquaintance with methods of
research. It will be seen from what follows that he also possessed the
gift of correct diagnosis, the capacity to pose to himself the problems
to be investigated, the persistence to solve them, and the drive needed
to get the results taken up by the people and firmly welded into the
practice of the country-side.

Clarke was most fortunate in the choice of his staff. He had associated
with him throughout two Indian officers--S. C. Banerji (afterwards Rai
Bahadur) and Sheikh Mahomed Naib Husain (afterwards Khan Bahadur).
Banerji, who possessed the dignity and repose of his race, was in charge
of the laboratories--always a model of order and efficiency--and was
accurate and painstaking almost beyond belief. Naib Husain was of a very
different temperament--hot-tempered and full of the energy and drive
needed to break new ground in crop production. His absorbing interest in
life was the Shahjahanpur farm and the condition of his crops and he
never spared himself to make all he undertook a success. Both these men
gave their lives to their work and both lived to see their efforts
crowned with success, and the Shahjahanpur farm the centre of perhaps
the most remarkable example of rural development so far achieved. No
European officer in India has ever had more loyal assistants; Indian
agriculture has never been served with more devotion. I saw much of
their work and watched the growth of the modest but efficient
organization they helped to build. It is a great regret to me that they
are not here to read this genuine tribute of admiration and respect from
a fellow worker of another race.

It had been the custom till 1912 in the United Provinces to keep their
scientific officers isolated from the practical side of agricultural
improvement, and there were no clear ideas how the combined scientific
and practical problems connected with cane cultivation should be
tackled. It did not strike any one that it would be necessary for the
scientific investigator to grow the crop and master the local
agriculture before any improvement could be devised and tried. When
therefore in 1911 Clarke asked to be provided with a farm, there was a
good deal of discussion and some amazement. The matter was referred to
the All-India Board of Agriculture in 1911, where the proposal was
severely criticized. The agricultural members did not like the idea of
scientific men having land of their own; the representatives of science
considered they would lose caste if another of their number took up
farming.

In 1912 I happened to be on tour in the United Provinces when the matter
came up for final decision. The Director of Agriculture asked my advice.
I strongly supported Clarke's proposal and assured the authorities that
great things would result if they gave their agricultural chemist the
best farm they could, and then left him alone to work out his own
salvation. This carried the day; a special sugar-cane farm was
established in 1912 near Shahjahanpur on the bank of the Kanout river
and on one of the main roads leading into the town. From 1912 to 1931,
an unbroken period of nineteen years, Clarke remained in charge of
Shahjahanpur in addition to the three posts he held: Agricultural
Chemist (1907-21), Principal of the Agricultural College (1919-21), and
Director of Agriculture (1921-31). From 1912 to 1921 he was there nearly
every week-end. Until he became Director of Agriculture in 1921, he was
at Shahjahanpur every year from Christmas until March for the sugar-cane
harvest and the planting of the next year's crop. It was during these
periods that he gained a first-hand knowledge of the Indian village, its
people, its fields, and its agricultural problems, which was to stand
him in such good stead when he was called upon to direct the
agricultural development of the Provinces in the early years of the
Montagu-Chelmsford Reforms.

The sugar-growing tract of northern India, the most important in the
country, is a broad strip of deep alluvial land about 500 miles in
length skirting the Himalayas. It begins in Bihar; it ends in the
Punjab, and reaches its greatest development in the Revenue Divisions of
Gorakhpur, Meerut, and Rohilkhand of the United Provinces. The soil is
easily cultivated and is particularly suitable for the root development
of the sugar-cane. The climate, however, is not particularly favourable
as the growing period is so short and confined to the rainy season--the
last half of June, July, August, and September--when the moist tropical
conditions created by the south-west monsoon are established. The rains
are followed by the cold season (October 15th to March 15th) during
which very little rain is received. After the middle of March the
weather again changes, becoming very hot and dry till the break of the
rains in June. During the hot weather the cane, which is usually planted
towards the end of February, has to be irrigated.

When work was started in 1912, the yield of stripped cane on 95 per
cent. of the sugar-cane area of the United Provinces was only 13 tons to
the acre, producing just over 1 ton of crude sugar (gur). The land was
fallowed during the previous rains and was well prepared for the crop by
15 to 20 shallow ploughings with the native plough. As in many other
Indian crops a good balance has been established, as a result of
age-long experience, between the methods of cultivation and the economic
capacity of the indigenous varieties. The methods of cultivation, the
nitrogen supply, and the kinds grown were all in correct relation the
one to the other. These varieties had been cultivated for at least
twenty centuries and were thin, short, and very fibrous with juice rich
in sugar in good seasons. They remind one more of the wild species of
the genus Saccharum than of the thick sugar-canes found in tropical
countries. Five or six varieties are grown together, each with a name,
usually of Sanskrit origin, denoting their qualities, and each is
readily recognized by the people.

The types of cane grown by the cultivators in the Rohilkhand Division
were first separated and an attempt was made to intensify the
cultivation of the best. The yield of cane was raised from 13 to 16 tons
per acre without deterioration in the quality of the juice, but further
intensification did not succeed. As much as 27 tons to the acre was
obtained, but the thin, watery juice contained so little sugar that it
was not worth extracting. The variety and the improved soil conditions
were not in correct relation. The leaf area developed by the indigenous
varieties was insufficient, in the short growing period of North India,
to manufacture the cellulose required for the fibre and other tissue of
so large a crop, and enough sugar to make the juice of economic value.
This was a most important experiment as it defined the general problem
and showed definitely what had to be done. To raise the out-turn of
sugar in the United Provinces, a combination of intensive methods of
cultivation with more efficient varieties, adapted to the very special
climatic conditions, would be necessary. These two problems were taken
up simultaneously: in all the subsequent work the greatest care was
taken to avoid the fragmentation of the factors, a rock on which so much
of the agricultural research of the present day founders.

Attention was then paid to the two chief factors underlying the problem:
(1) the discovery of a suitable cane, and (2) the study of intensive
cane growing with the object of finding out the maximum yield that could
be obtained.

The collection of cane varieties at Shahjahanpur included a Java
seedling--POJ 213 which was exactly suited to the local soil and climate
and which responded to intensive cultivation. This Java cane was a
hybrid. Its pollen parent was the Rohilkhand variety Chunni, which had
been given to the Dutch experts, who visited India twenty years earlier,
by the Rosa Sugar Factory. Chunni was immune to sereh--a serious disease
then threatening the sugar industry in Java--and, when crossed with rich
tropical canes, produced immune or very resistant seedlings of good
quality, widely known throughout the world as POJ (Passoerean Ost-Java)
seedlings. POJ 213 proved invaluable during the early stages of the
Shahjahanpur work. It was readily accepted by the cultivators among whom
it was known as 'Java'. A large area was soon grown in Rohilkhand and it
saved the local sugar industry then on the verge of extinction. Most
important of all it created an interest in new kinds of sugar-cane and
prepared the ground for the great advance, which came a few years later
when a Coimbatore seedling--Co 213--raised by the late Dr. Barber,
C.I.E.--replaced it.

Clarke had not been long in the United Provinces before he noticed that
the soil of the Gangetic plain could be handled in much the same way as
that of the Holland Division of Lincolnshire, where the intensive
cultivation of potatoes had been introduced sixty or seventy years
before and brought to a high state of perfection. Both soils are
alluvial though of widely different date. The problems connected with
the intensive cultivation of potatoes in Lincolnshire and sugar-cane in
the United Provinces have a great deal in common. Both crops are
propagated vegetatively, and in both it is a most important point to
produce the soil conditions necessary to develop the young plant
quickly, so that it is ready to manufacture and store a large quantity
of carbohydrate in a short period of favourable climatic conditions.
When the intensification of sugar-cane cultivation was begun at
Shahjahanpur, the lessons learnt in the potato fields of Lincolnshire
were at once applied. During the fallow which preceded the crop the land
was cultivated and, as soon as possible after the retreat of the
monsoon, the farm-yard manure was put on and ploughed in. This gave the
time necessary for a valuable supply of humus to be formed in the top
layer of the soil. The sugar-cane was planted in shallow trenches 2 feet
wide, 4 feet from centre to centre. The soil from each trench was
removed to a depth of 6 inches and piled on the 2 feet space left
between each two trenches, the whole making a series of ridges as
illustrated in Fig. 6.


FIG. 6. Trench System at Shahjahanpur


As soon as the trenches are made in November, they are dug with a local
tool (kasi) to a further depth of 9 inches, and the oilcake, or whatever
concentrated organic manure is available, is thoroughly mixed with the
soil of the floor of the trenches and allowed to remain, with occasional
digging, till planting time in February. The thorough cultivation and
manuring of the trenches at least two months, and preferably three,
before the canes are planted, proved to be essential if the best results
were to be obtained. Readers familiar with the methods of sugar-cane
cultivation in Java will at once realize that this Shahjahanpur method
is a definite advance on that in use in Java, in that the use of
artificials is entirely unnecessary. Hand-made trenches always give
better yields than those made by mechanical means--an interesting
result, which has often been obtained elsewhere, but which has never
been adequately explained. It may be that speed in cultivation is an
adverse factor in the production of tilth.

At first heavy dressings of organic manures like castor cake meal at the
rate of about 2,870 lb. to the acre were used in the trenches. This
contains about 4.5 per cent. of nitrogen, so that 2,870 lb. is
equivalent to 130 lb. of nitrogen to the acre. This heavy manuring,
however, was soon reduced after the introduction of the method of
green-manuring described below. When green-manuring was properly carried
out, the dung applied before making the trenches could be reduced to
half or even less.

At first the trenches were irrigated about a month before planting and
lightly cultivated when dry enough. These operations promoted the decay
of the manure, and allowed for abundant soil aeration. The canes were
planted in the freshly dug moist rich earth towards the end of February.
Later this preliminary watering was dispensed with. The cuttings were
planted in the dry earth, and lightly watered the next day. This saved
one irrigation and proved to be an effective protection from white ants
(Termites), which often attacked the cane cuttings unless these started
growth at once and the young plants quickly established themselves. Four
light waterings, followed in every case by surface cultivation, were
necessary before the break of the monsoon in June. As soon as the young
canes were about 2 feet high, and were filtering vigorously, the
trenches were gradually filled in, beginning about the middle of May and
completing the operation by the end of the month. Before the rains
began, the earthing up of the canes commenced. It was completed by about
the middle of July (Fig. 7).


FIG. 7. Earthing up sugar-cane at Shahjahanpur, July 10th, 1919


One of the consequences of earthing up canes, grown in fertile soil,
observed by Clarke was the copious development of fungi which were
plainly visible as threads of white mycelium all through the soil of the
ridges, and particularly round the active roots. As the sugar-cane is a
mycorrhiza-former there is little doubt that the mycelium, observed in
such quantities, was connected with the mycorrhizal association. The
provision of all the factors needed for this association--humus,
aeration, moisture, and a constant supply of active roots--probably
explains why such good results have always followed this method of
growing the cane and why the crops are so healthy. When grown on the
flat, want of soil aeration would always be a limiting factor in the
full establishment of the mycorrhiza.

The operation of earthing up serves four purposes: (1) the succession of
new roots, arising from the lower nodes, thoroughly combs the highly
aerated and fertile soil of the ridges; (2) the conditions suitable for
the development of the mycorrhizal association are provided; (3) the
standing power of the canes during the rains is vastly improved; and (4)
the excessive development of colloids in the surface soil is prevented.
If this earthing up is omitted, a heavy crop of cane is almost always
levelled by the monsoon gales; crops which fall down during the rains
never give the much-prized light coloured crude sugar. The production of
colloids in the surface soil, when the canes are grown on the flat,
always interferes with soil aeration during the period when sugar is
being formed; crops which ripen under conditions of poor soil aeration
never give the maximum yield.

An essential factor in obtaining the highest efficiency in this ridging
system is good surface drainage. This was achieved by lowering the earth
roads and paths which, when grassed over, acted as very efficient drains
for carrying off the excess rainfall during the monsoon. The surface
water collected in the trenches which were suitably connected with the
system of lowered paths and roads. By this means the drainage crept
away, in thin sheets of clear water, to the river without any loss of
organic matter or of fine soil particles. The grass carpet acted as a
most efficient filter and was at the same time manured. The roads
yielded good crops of grass for the work cattle. This simple device
should be utilized wherever possible to prevent both water-logging and
soil erosion.

The results of this intensive method of cane cultivation--based on the
growth of efficient varieties, proper soil aeration, good surface
drainage, carefully controlled irrigation, and an adequate supply of
organic matter--were astounding. In place of 13 tons of cane and just
over a ton of sugar per acre, a yield of just over or just under 36 tons
of cane and 3-1/2 tons of sugar per acre was obtained for a period of
twenty years--year in and year out. These are the figures for the farm
as a whole. The yield of sugar had been trebled. Such a result has
rarely been obtained for any crop in so short a time and by such simple
means. In a few cases yields as high as 44 tons of cane and 4-1/2 tons
of sugar were obtained, figures which probably represent the highest
possible production in the climate of the United Provinces.

In working out this method of cane growing in northern India, two
critical periods in sugar production were observed: (1) May and early
June when the tillers and root system are developing, and (2) August and
September when the main storage of sugar takes place. A check received
at either of these periods permanently reduces the yield. The acre yield
of sugar is positively and closely correlated with the amount of nitrate
nitrogen in the soil during the first period and with soil moisture,
soil aeration, and atmospheric humidity in the second period. Any
improvement in cane growing must therefore take into account these two
principles.

A new method of intensive cane cultivation had been devised and put into
successful practice on a field scale at a State Experiment Station; the
first step in improving sugar production had been taken. It was now
necessary to fit this advance into a system of agriculture made up of a
multitude of small holdings, varying from an average of 4 acres in the
eastern districts to 8 acres in the western half of the province. Each
holding is not only minute but it is divided into tiny fields, scattered
over the village area, which is by no means uniform in fertility.
Moreover, the farmers of these small holdings possess practically no
capital for investment in intensive agriculture. How could the average
cultivator obtain the necessary manure? The solution of this problem
entailed a detailed study of the nitrogen cycle on the Gangetic
alluvium, the relation between climate, methods of cultivation, and the
accumulation of soil nitrate as well as the discovery of what amounts to
a new method of green-manuring for sugar-cane. These investigations were
set in motion the moment the possibilities of intensive cane growing
became apparent.

The study of the nitrogen cycle, in any locality, naturally includes an
intimate acquaintance with the local agriculture. The outstanding
feature of the agricultural year in the United Provinces is the rapidity
with which the seasons change, and the wide variation in their
character. The most important of these abrupt transitions are: (1)
change from the excessive dryness and high temperatures of April, May,
and early June to the moist tropical conditions which set in when the
summer crops are sown at the end of June, immediately after the break of
the southwest monsoon, and (2) the sudden transition from high humidity,
high temperature, and a saturated condition of the soil, at the end of
the monsoon in September, to the dry temperate conditions which obtain
when the autumn sowings of food crops take place in October. These
sudden seasonal changes impose definite limits on what can be done to
increase production. There is very little time for the preparation of
the land, or for the manufacture of plant food by biological agencies;
the period of active growth of the crop is severely limited. The former
influences the methods of cultivation and manuring; the latter the
selection of varieties. The wide difference between the two agricultural
seasons in the United Provinces is best realized in the autumn (November
and December), when crops of ripening cane and growing wheat are to be
seen side by side in adjacent fields.

How do the summer and autumn crops, often raised in this area under
extensive methods, manage to obtain a supply of nitrate without any
added manure, and how is it that the soil fertility of the Gangetic
alluvium remains so constant? To begin to answer these questions, soil
borings from a typical unmanured area--fallowed after the wheat crop
which was removed in April--were systematically examined and the nitric
nitrogen estimated directly by Schloesing's method.


PLATE VII. Nitrate Accumulation in the Gangetic Alluvium


The results, as well as the details of temperature and rainfall, are
given in Plate VII. The curve brings out clearly: (1) the large and
rapid formation of nitrate as the temperature rises in February and
March, just at the time when the young sugar-cane plant takes in its
supply of nitrogen, (2) the almost complete disappearance of nitrates
from the soil after the first falls of heavy rain--these are partly
washed out and partly immobilized by fungous growth, provided the humus
content of the soil has been maintained, (3) the absence of
nitrification in the saturated soil during the monsoon, (4) another
accumulation of nitrate (less rapid and less in quantity than in the
spring) which occurs in the autumn, following the drying of the soil at
the end of the rains, combined with improved aeration, the result of
frequent surface cultivation. Five ploughings to a depth of 3 inches,
followed by the levelling beam, were given between September 25th and
November 31st. These accumulations, obviously the result of biological
processes, fit in with the quantitative requirements of the summer and
autumn crops, which need immediate supplies of nitrogen as soon as the
seed germinates.

When we compare these results on nitrate accumulation with what the
Indian cultivator is doing, we are lost in admiration of the way he sets
about his task. With no help from science, and by observation alone, he
has in the course of ages adjusted his methods of agriculture to the
conservation of soil fertility in a most remarkable manner. He is by no
means the ignorant and backward villager he is sometimes represented to
be, but among the most economical farmers in the world as far as the
management of the potent element of fertility--combined nitrogen--goes,
and tropical agriculture all over the world has much to learn from him.
The sugar grower of the great plains of India cannot take a heavy
overdraft of nitrogen from his soil. He has only a limited store--the
small current account provided by non-symbiotic nitrogen fixation and
the capital stock of humus needed to maintain the crumb structure and
the general life of the soil. He must make the most of his current
account; he dare not utilize any of his capital. He has in the course of
ages instinctively devised methods of management which furfil these
conditions. He does not over-cultivate or cultivate at the wrong time.
Nothing is done to over-oxidize his precious floating nitrogen or to
destroy his capital of humus. He probably does more with a little
nitrogen than any farmer in the world outside China. For countless ages
he has been able to maintain the present standard of fertility.

If the production of sugar was to be raised, obviously the first step
was to provide more nitrate for the critical growth period of May and
June, when the tillers and root system are developing. The conventional
method would be to stimulate the crop by the addition of factory-made
and imported fertilizers such as sulphate of ammonia. There are weighty
objections to such a course. The cultivator could not afford them; the
supply might be cut off in time of war; the effect of adding these
substances to the soil would be to upset the balance of soil
fertility--the foundation of the Indian Empire--by setting in motion
oxidation processes which would eat into India's capital, and burn up
the vital store of soil humus. Increased crops would indeed be obtained
for a few years, but at what a cost--lowered soil fertility, lowered
production, inferior quality, diseases of crops, of animals, and of the
population, and finally diseases of the soil itself, such as soil
erosion and a desert of alkali land! To place in the hands of the
cultivator such a means of temporarily increasing his crops would be
more than a mere error of judgement: it would be a crime. The use of
artificials being ruled out altogether, some alternative source of
nitrogen had to be found.

Any intensive method of sugar growing in the United Provinces must
accomplish two things: (1) the normal accumulations of nitrates in the
soil at the beginning of the rains must be fully utilized, and (2) the
content of soil organic matter must be raised and the biological
processes speeded up so that these natural accumulations can be
increased.

The problem of making use of the nitrate naturally formed in order to
raise the content of organic matter was solved in a very neat
fashion--by a new method of green-manuring. The fallow, which ordinarily
precedes cane, was used to grow a crop of san hemp with the help of
about 4 tons of farm-yard manure to the acre. This small dressing of
cattle manure had a remarkable effect on the speed of growth and also on
the way the green crop decayed when it was ploughed in. Yields of 8 tons
of green-manure were produced in about 60 days which added nearly 2 tons
of organic matter, or 75 lb. of nitrogen, to each acre. In this way the
nitrates accumulated at the break of the rains were absorbed and
immobilized; a large mass of crude organic material was provided by the
green manure itself and by the small dressing of farm-yard manure
applied before sowing. Sheet composting took place in the surface soil.

The early stages of decomposition need ample moisture. The rainfall
after the green crop was ploughed in was carefully watched. If it was
less than 5 inches in the first fortnight in September, the fields were
irrigated. In this way an abundant fungous growth was secured on the
green-manure as the land slowly dried. The conversion of the whole of
the green crop into humus was not complete until the end of November.
Nitrification then began, slowly, owing to the low temperatures of the
cold weather in North India and at a season when there is little risk of
loss. It was not until the newly planted canes were watered at the end
of February and the temperature rose at the beginning of the hot weather
that all the available nitrogen in the freshly prepared humus was
rapidly nitrified to meet the growing needs of the developing root
system of the cane. This means simply that a definite time is required
for the formation of humus, whether it takes place in the soil by sheet
composting or in the compost heap, a longer period being required in the
soil than in the heap. The gradual filling of the trenches and the
watering of the canes during the hot weather continued the nitrification
process, which was carried a stage farther by the earthing up of the
canes. The provision of drainage trenches between the rows reduced to a
minimum any losses of nitrogen due to poor soil aeration following the
formation of soil colloids. The canes were thus provided with ample
nitrate throughout the growth period. The conditions necessary for the
mycorrhizal association were also established.


PLATE VIII. Nitrate Accumulation, Green-Manure Experiement,
Shahjahanpur, 1928-9


The effects of green-manuring on the nitrate supply is shown in Plate
VIII. It will be seen that the enrichment of the soil with humus has
markedly increased the amount of nitrate formed during the crucial
period (March to June) when the rapidly growing cane absorbs most of its
supplies.

The yields of cane and of raw sugar of twenty-seven randomized plots in
the green-manured and control plots are given below:


TABLE II

Effect of green manuring on sugar-cane

                 Sugar-cane maunds   Raw sugar maunds,   Dry matter maunds,
              (82-2/7 lb.), per acre      per acre            per acre

Green-manure      847.0                     87.0                246.0
Control           649.0                     67.2                200.1


These control plots are representative of the fertile plots of the
Shahjahanpur Experiment Station, not of the fields of the cultivators.

The crop in the field is shown in Plate IX. The practical result of this
simple method of intensive cane growing worked out at a profit of 6 pounds
an acre. These satisfactory results were reflected in the annual statement
of income and expenditure of the Shahjahanpur Experiment Station. For
many years income exceeded expenditure by about 50 per cent.


PLATE IX. Green-manure Experiment, Shahjahanpur, 1928-9


The question therefore of the practical value of the work done at this
Station needed no argument. It was obvious. By the help of green-manure
alone, supplemented by a small dressing of cattle dung, the yield of
cane was raised from 13 to over 30 tons to the acre; the yield of sugar
from 1 ton to over 3 tons.

The effect of the intensive cultivation of sugar-cane is not confined to
that crop. The residual fertility and the deep cultivation of the
trenches enabled bumper crops of Pusa wheat and gram--the two rotation
crops grown with cane at Shahjahanpur--to be obtained. These were more
than three times the average yields obtained by the cultivators. In one
case in a field of 31 acres, Pusa 12 wheat gave 35 maunds to the acre
with one irrigation of 4 inches in November. The preceding cane crop was
Ashy Mauritius, which yielded 34.7 tons to the acre.

In the early days of the Shahjahanpur farm the effect of the cane
trenches on the following wheat crop was very pronounced. The surface of
the wheat fields resembled a sheet of corrugated iron, the ridges
corresponding to the trenches. After a few sugar crops this condition
passed off, and the wheat appeared uniform; all the land had been raised
to the new level of fertility.

It is now possible to record the various stages passed through in this
study of intensive sugar production:

1. The unimproved crop in an average year yielded 350 maunds per acre (1
maund = 82-1/7 lb.; 27.2 maunds = 1 ton).

2. The best indigenous varieties, grown at their maximum capacity with
slightly deeper ploughing than the cultivator gives and a small quantity
of manure, gave 450 maunds per acre.

3. The introduction of new varieties like POJ 213 and Co 213, grown on
the flat with the same cultivation as (2) above, gave 600 maunds per
acre. The increment due to variety was therefore 150 mounds per acre
(600-450).

The use of new varieties plus green-manure on the flat without trenches
yielded 800 maunds per acre. The increment due to green-manure was
therefore 200 maunds per acre (800-600).

Intensive cultivation in trenches, with green-manure plus the manuring
of the trenches with castor cake meal at the rate of 1,640 lb. per acre,
yielded 1,000 maunds per acre. The increment due to improved soil
aeration and an adequate supply of humus in the trenches was therefore
200 maunds per acre (1,000-800).

The very highest yield ever obtained at Shahjahanpur by the use of (5)
above was 1,200 maunds per acre. The additional increment, when all the
factors were functioning at or near their optima was 200 maunds per acre
(1,200--1,000).

It will be seen that a combination of variety, green manuring, and
correct soil management, including the manuring of the trenches, added
650 maunds per acre (1,000-350) and that increases of 850 maunds per
acre are possible (1,200-350). In the intensive trench method the plant
attains an exceptionally high efficiency in the synthesis of
carbohydrates. In an out-turn test at Shahjahanpur 1,200 maunds of
stripped cane per acre contained 17 per cent. of fibre (mostly pure
cellulose), 12 per cent. of sucrose, and 1 per cent. of invert sugar.
The total quantity of carbohydrate synthesized per acre in about four
months of active growth was 204 maunds of cellulose, 144 maunds of
sucrose, and 12 maunds of invert sugar; in all 360 maunds (13.2 tons)
per acre of carbohydrates. This means 3.3 tons per acre during the
period of active growth when every assistance as regards choice of
variety, soil fertility, and soil management had been provided.

We have in these Shahjahanpur results a perfect example of the
manufacture of humus by means of a green-manure crop and its utilization
afterwards. Success depends on two things: (1) a knowledge of the
nitrogen cycle and of the conditions under which humus is manufactured
and utilized, and (2) an effective agricultural technique based on these
biological principles.

The stage was now set for getting the Shahjahanpur results taken up by
the cultivators. Two questions had to be settled:

1. Should an attempt be made to introduce the full Shahjahanpur
methods--improved green-manuring, manured trenches, and new
varieties--or should a beginning be made with green-manuring plus new
varieties with or without trenches according to circumstances? It was
finally decided to introduce the new variety along with the new method
of green-manuring and to omit the trenches. This decision was made
because of the scarcity of manure for the full Shahjahanpur method. This
difficulty, however, was removed in 1931, the year Clarke left India,
with the introduction of the Indore Process, which could have provided
every village with an adequate supply of manure for intensive methods.

2. Should a large organization be created for bringing the results to
the notice of the villagers? At this point the Agricultural Department
was transferred to the control of an Indian Minister, and Clarke became
Director of Agriculture in the United Provinces and a member of the
Legislative Council, offices which he held with short temporary breaks
for ten years. He was thus provided with administrative powers for
developing to the full the results of his work as a scientific
investigator. The first two Ministers under whom he served, Mr. C. Y.
Chintamani (now Sir Chirravoori) and the Nawab of Chhatari, though of
widely different political views, were in complete agreement regarding
the necessity of agricultural development and both gave their
unqualified support to the proposals which were placed before them,
while in the Council itself members of every shade of opinion, from the
extreme Left to the extreme Right, demanded a large extension of
agricultural work. The annual debate on the agricultural budget was one
of the events of the year. From 1921 to 1931 the financial proposals of
Government for agricultural improvement were passed without an adverse
vote of any kind. This was incidentally an example of the success that
can be obtained under a popular Government in India by a Department when
it is backed by efficient technical work. A large number of Members of
the Council were influential landlords, deeply interested in the
development of the country-side, and they, and many others outside the
Council, were anxious to take up something of practical value. It was
therefore decided to start, in the main sugar-growing areas, State-aided
private farms for the purpose of demonstrating the new methods of
growing cane and providing the large quantity of planting material
required for the extension of the area under the new varieties.

The amount of aid given by the State was small, about Rs. 2,000 to Rs.
3,000 for every farm. An agreement was entered into, between the
landlords and the Agricultural Department, by which the former agreed to
put down a certain area under Co 213, to green-manure the land and to
conduct the cultivation on Shahjahanpur lines. Cuttings were to be
supplied to the locality at a certain fixed rate. In this way the
example and influence of the landlords was secured at very small cost.
At the same time the hold of the Agricultural Department on the
country-side was increased and strengthened--the landlords became to all
intents and purposes an essential portion of the higher staff of the
Agricultural Department. They differed, however, from the ordinary
District staff in two important respects: (1) they possessed an
influence far surpassing that of the ablest members of the Agricultural
Department; (2) they were unofficial and unpaid.

The contribution of the Indian landowners to this work was of the
greatest importance. Without their active support and their public
spirit in opening farms, and thus setting up a multitude of local
centres for demonstrating on a practical scale the new method of sugar
production, and at the same time providing the material for planting at
a low rate, the Agricultural Department would have had to fall back on
itself for getting the improvements taken up. In place of the
demonstration farms, provided by the landlords at an exceedingly low
cost, the Government would have had to acquire land and start local
farms for advertising the new method and for the supply of plant
material. The cost would have been colossal and quite beyond the
resources of Government. In place of the influence and personal interest
of the natural leaders of the country-side, the Agricultural Department
would have had to rely on the work of a host of low-paid subordinates,
and would have had to increase its inspecting staff out of all
knowledge. An unwieldy and expensive organization would have been the
result. All this was rendered unnecessary by the admirable system of
private farms. The idea of using the landlords in agriculture began in
Oudh in 1914, when a number of private farms were started on the estates
of the Talukdars for demonstrating the value of the new Pusa wheats and
for producing the large quantities of seed needed. Clarke extended this
idea to all parts of the Provinces, and showed how the results obtained
at one experimental farm could be expanded rapidly and effectively by
enlisting the active help of the landowners. He provided them with an
opportunity, eagerly taken up, of showing their value to the
community--that of leadership in developing the country-side by
practical examples of better agriculture which their tenants and
neighbours could copy. Landlords all the world over will act in a
similar way once the Agricultural Departments can provide them with
results of real value.

The magnitude of these operations and the speed with which they were
conducted will be obvious from the following summary of the final
results. In 1916-17 Clarke received about 20 lb. of cuttings of Co 213
from Coimbatore for trial. In 1934-5, 33,000,000 tons of this variety
were produced in the United Provinces. The value of the crop of Co 213
cane to the cultivator, at the low minimum rate fixed by Government for
sugar-cane under the Sugar-Cane Act of 1934, was over 20,000,000 pounds,
more than half of which was entirely new wealth. The value of the sugar
which could be manufactured from this was 42,000,000 pounds. A large sum
was distributed in factory wages, salaries, and dividends, to say nothing
of the benefit to the British engineering trade and the effect on
employment in Great Britain of orders for over 10,000,000 pounds worth of
machinery for new factories. There was no question of glutting an
over-stocked market in India. All the additional sugar and sugar
products were readily absorbed by the local markets.

Here we have a successful effort in directed economy--the development of
imperial resources by simple technical improvements in agriculture,
rendered possible by the protection of a valuable imperial market by a
straight tariff.

Since Clarke retired from the Indian Agricultural Department, two new
factors--both favourable--have been in operation, which make it easy to
follow up this initial success. The difficulty of producing enough humus
in the villages for the trench system has been removed by the Indore
system of composting. Irrigation has been improved in the sugar-growing
tracts by the completion of the Sarda Canal and the provision of cheap
electric power for raising water from wells. The two essentials for
intensive agriculture--humus and water--are now available. Before long a
detailed account of the progress made by the introduction of the full
Shahjahanpur method will no doubt be available. The story begun in this
chapter can then be carried on another stage. It will make interesting
and stimulating reading.



BIBLIOGRAPHY

CLARKE, G., BAYERJEE, S. C., NAIB HUSAIN, M., and QAYUM, A.
'Nitrate Fluctuations in the Gangetic Alluvium,
and Some Aspects of the Nitrogen Problem in India', Agricultural Journal
of India, xvii, 1922, p. 463.

CLARKE, G. 'Some Aspects of Soil Improvement in Relation to Crop
Production', Proc. of The Seventeenth Indian Science Congress,
Asiatic Society of Bengal, Calcutta, 1930, p. 23.





PART V CONCLUSIONS AND SUGGESTIONS




CHAPTER XV



A FINAL SURVEY


The capital of the nations which is real, permanent, and independent of
everything except a market for the products of farming, is the soil. To
utilize and also to safeguard this important possession the maintenance
of fertility is essential.

In the consideration of soil fertility many things besides agriculture
proper are involved--finance, industry, public health, the efficiency of
the population, and the future of civilization. In this book an attempt
has been made to deal with the soil in its wider aspects, while devoting
due attention to the technical side of the subject.

The Industrial Revolution, by creating a new hunger--that of the
machine--and a vast increase in the urban population, has encroached
seriously on the world's store of fertility. A rapid transfer of the
soil's capital is taking place. This expansion in manufacture and in
population would have made little or no difference had the waste
products of the factory and the town been faithfully returned to the
land. But this has not been done. Instead, the first principle of
agriculture has been disregarded: growth has been speeded up, but
nothing has been done to accelerate decay. Farming has become
unbalanced. The gap between the two halves of the wheel of life has been
left unbridged, or it has been filled by a substitute in the shape of
artificial manures. The soils of the world are either being worn out and
left in ruins, or are being slowly poisoned. All over the world our
capital is being squandered. The restoration and maintenance of soil
fertility has become a universal problem.

The outward and visible sign of the destruction of soil is the speed at
which the menace of soil erosion is growing. The transfer of capital, in
the shape of soil fertility, to the profit and loss account of
agriculture is being followed by the bankruptcy of the land. The only
way this destructive process can be arrested is by restoring the
fertility of each field of the catchment area of the rivers which are
afflicted by this disease of civilization. This formidable task is going
to put some of our oversea administrations to a very severe test.

The slow poisoning of the life of the soil by artificial manures is one
of the greatest calamities which has befallen agriculture and mankind.
The responsibility for this disaster must be shared equally by the
disciples of Liebig and by the economic system under which we are
living. The experiments of the Broadbalk field showed that increased
crops could be obtained by the skilful use of chemicals. Industry at
once manufactured these manures and organized their sale.

The flooding of the English market with cheap food, grown anywhere and
anyhow, forced the farmers of this country to throw to the winds the old
and well-tried principles of mixed farming, and to save themselves from
bankruptcy by reducing the cost of production. But this temporary
salvation was paid for by loss of fertility. Mother earth has recorded
her disapproval by the steady growth of disease in crops, animals, and
mankind. The spraying machine was called in to protect the plant;
vaccines and serums the animal; in the last resort the afflicted live
stock are slaughtered and burnt. This policy is failing before our eyes.
The population, fed on improperly grown food, has to be bolstered up by
an expensive system of patent medicines, panel doctors, dispensaries,
hospitals, and convalescent homes. A C3 population is being created.

The situation can only be saved by the community as a whole. The first
step is to convince it of the danger and to show the road out of this
impasse. The connexion which exists between a fertile soil and healthy
crops, healthy animals and, last but not least, healthy human beings
must be made known far and wide. As many resident communities as
possible, with sufficient land of their own to produce their vegetables,
fruit, milk and milk products, cereals, and meat, must be persuaded to
feed themselves and to demonstrate the results of fresh food raised on
fertile soil. An important item in education, both in the home and in
the school, must be the knowledge of the superiority in taste, quality,
and keeping power of food, like vegetables and fruit, grown with humus,
over produce raised on artificials. The women of England--the mothers of
the generations of the future--will then exert their influence in food
reform. Foodstuffs will have to be graded, marketed, and retailed
according to the way the soil is manured. The urban communities (which
in the past have prospered at the expense of the soil) will have to join
forces with rural England (which has suffered from exploitation) in
making possible the restitution to the country-side of its manurial
rights. All connected with the soil--owners, farmers, and
labourers--must be assisted financially to restore the lost fertility.
Steps must then be taken to safeguard the land of the Empire from the
operations of finance. This is essential because our greatest possession
is ourselves and because a prosperous and contented country-side is the
strongest possible support for the safeguarding of the country's future.
Failure to work out a compromise between the needs of the people and of
finance can only end in the ruin of both. The mistakes of ancient Rome
must be avoided.

One of the agencies which can assist the land to come into its own is
agricultural research. A new type of investigator is needed. The
research work of the future must be placed in the hands of a few men and
women, who have been brought up on the land, who have received a
first-class scientific education, and who have inherited a special
aptitude for practical farming. They must combine in each one of them
practice and science. Travel must be included in their training because
a country like Great Britain, for instance, for reasons of climate and
geology, cannot provide examples of the dramatic way in which the growth
factors operate.

The approach to the problems of farming must be made from the field, not
from the laboratory. The discovery of the things that matter is
three-quarters of the battle. In this the observant farmer and labourer,
who have spent their lives in close contact with Nature, can be of the
greatest help to the investigator. The views of the peasantry in all
countries are worthy of respect; there is always good reason for their
practices; in matters like the cultivation of mixed crops they
themselves are still the pioneers. Association with the farmer and the
labourer will help research to abandon all false notions of prestige;
all ideas of bolstering up their position by methods far too reminiscent
of the esoteric priesthoods of the past. All engaged on the land must be
brother cultivators together; the investigator of the future will only
differ from the farmer in the possession of an extra implement--
science--and in the wider experience which travel confers. The future
standing of the research worker will depend on success: on ability
to show how good farming can be made still better. The illusion
that the agricultural community will not adopt improvements will
disappear, once the improver can write his message on the land itself
instead of in the transactions of the learned societies. The natural
leaders of the country-side, as has been abundantly proved in rural
India, are only too ready to assist in this work as soon as they are
provided with real results. No special organization, for bringing the
results of the experiment stations to the farmer, is necessary.

The administration of agricultural research must be reformed. The vast,
top-heavy, complicated, and expensive structure, which has grown up by
accretion in the British Empire, must be swept away. The time-consuming
and ineffective committee must be abolished. The vast volume of print
must be curtailed. The expenditure must be reduced. The dictum of Carrel
that 'the best way to increase the intelligence of scientists would be
to reduce their number' must be implemented. The research applied to
agriculture must be of the very best. The men and women who are capable
of conducting it need no assistance from the administration beyond the
means for their work and protection from interference. One of the chief
duties of the Government will be to prevent the research workers
themselves from creating an organization which will act as a bar to
progress.

The base line of the investigations of the future must be a fertile
soil. The land must be got into good heart to begin with. The response
of the crop and the animal to improved soil conditions must be carefully
observed. These are our greatest and most profound experts. We must
watch them at work; we must pose to them simple questions; we must build
up a case on their replies in ways similar to those Charles Darwin used
in his study of the earthworm. Other equally important agencies in
research are the insects, fungi, and other micro-organisms which attack
the plant and the animal. These are Nature's censors for indicating bad
farming. To-day the policy is to destroy these priceless agencies and to
perpetuate the inefficient crops and animals they are doing their best
to remove. To-morrow we shall regard them as Nature's professors of
agriculture and as an essential factor in any rational system of
farming. Another valuable method of testing our practice is to observe
the effect of time on the variety. If it shows a tendency to run out,
something is wrong. If it seems to be permanent, our methods are
correct. The efficiency of the agriculture of the future will therefore
be measured by the reduction in the number of plant breeders. A few only
will be needed when soils become fertile and remain so.

Nature has provided in the forest an example which can be safely copied
in transforming wastes into humus--the key to prosperity. This is the
basis of the Indore Process. Mixed vegetable and animal wastes can be
converted into humus by fungi and bacteria in ninety days, provided they
are supplied with water, sufficient air, and a base for neutralizing
excessive acidity. As the compost heap is alive, it needs just as much
care and attention as the live stock on the farm; otherwise humus of the
best quality will not be obtained.

The first step in the manufacture of humus, in countries like Great
Britain, is to reform the manure heap--the weakest link in Western
agriculture. It is biologically unbalanced because the micro-organisms
are deprived of two things needed to make humus--cellulose and
aufficient air. It is chemically unstable because it cannot hold itself
together--valuable nitrogen and ammonia are being lost to the
atmosphere. The urban centres can help agriculture, and incidentally
themselves, by providing the farmers with pulverized town wastes for
diluting their manure heaps and, by releasing, for agriculture and
horticulture, the vast volumes of humus lying idle in the controlled
tips.

The utilization of humus by the crop depends partly on the mycorrhizal
association--the living fungous bridge which connects soil and sap.
Nature has gone to great pains to perfect the work of the green leaf by
the previous digestion of carbohydrates and proteins. We must make the
fullest use of this machinery by keeping up the humus content of the
soil. When this is done, quality and health appear in the crop and in
the live stock.

Evidence is accumulating that such healthy produce is an important
factor in the well-being of mankind. That our own health is not
satisfactory is indicated by one example. Carrel states that in the
United States alone no less than 700,000,000 pounds a year is spent in
medical care. This sum does not include the loss of efficiency resulting
from illness. If the restitution of the manurial rights of the soils of
the United States can avoid even a quarter of this heavy burden, its
importance to the community and to the future of the American people
needs no argument. The prophet is always at the mercy of events;
nevertheless, I venture to conclude this book with the forecast that at
least half the illnesses of mankind will disappear once our food
supplies are raised from fertile soil and consumed in a fresh condition.





APPENDIXES




APPENDIX A



COMPOST MANUFACTURE ON A TEA ESTATE IN BENGAL


The Gandrapara Tea Estate is situated about 5 miles south of the
foothills of the Himalayas in North-East India in the district called
the Dooars (the doors of Bhutan). The Estate covers 2,796 acres, of
which 1,242 are under tea, and it includes 10 acres of tea seed bushes.
There are also paddy or rice land, fuel reserve, thatch reserves,
bamboos, tuna oil, and grazing land. The rainfall varies from 85 to 160
inches and this amount falls between the middle of April and the middle
of October, when it is hot and steamy and everything seems to grow.

The cold-weather months are delightful, but from March till the monsoon
breaks in June the climate is very trying.

There are approximately 2,200 coolies housed on the garden; most of
these originally came from Nagpur, but have been resident for a number
of years. The Estate is a fairly healthy one, being on a plateau between
large rivers; and there are no streams of any kind near or running
through the property. All drainage is taken into a near-by forest and
into waste land. The coolies are provided with houses, water-supply,
firewood, medicines, and medical attention free, and when ill they are
cared for in the hospital freely. Ante-natal and post-natal cases
receive careful attention and are inspected by the European Medical
Officer each week and paid a bonus; careful records of babies and their
weights are kept and their feeding studied; the Company provides
feeding-bottles, 'Cow and Gate' food, and other requirements to build up
a coming healthy labour force. As we survey all living things on the
earth to-day we have little cause to be proud of the use to which we
have put our knowledge of the natural sciences. Soil, plant, animal, and
man himself--are they not all ailing under our care?

The tea plant requires nutrition and Sir Albert Howard not only wants to
increase the quality of human food, but in order that it may be of
proper standard, he wants to improve the quality of plant food. That is
to say, he considers the fundamental problem is the improvement of the
soil itself--making it healthy and fertile. 'A fertile soil,' he says,
'rich in humus, needs nothing more in the way of manure: the crop
requires no protection from pests: it looks after itself.' . . .

In 1934 the manufacture of humus on a small scale was instituted under
the 'Indore method' advocated by Sir Albert Howard. The humus is
manufactured from the waste products of tea estates. All available
vegetable matter of every description, such as Ageratum, weeds, thatch,
leaves, and so forth, are carefully collected and stacked, put into pits
in layers, sprinkled with urinated earth to which a handful of wood
ashes has been added, then a layer of broken-up dung, and soiled
bedding; the contents are then watered with a fine spray--not too much
water but well moistened. This charging process is continued till the
pit is full to a depth of from 3 to 4 feet, each layer being watered
with a fine spray as before.


PLATE X: Plan of the Compost Factory, Gandrapara Tea Estate


To do all this it was most necessary to have a central factory, so that
the work could be controlled and the cost kept as low as possible. A
central factory was erected; details are given in the plan (Plate X);
there are 41 pits each 31 x 15 x 3 feet deep; the roofs over these pits
are 33 by 17 feet, space between sheds 12 feet and between lines of
sheds 30 feet; also between sheds to fencing 30 feet; this allows
materials to be carted direct to the pits and also leaves room for
finished material. Water has been laid on, a 2-inch pipe with l-inch
standards and hydrants 54 feet apart, allowing the hose to reach all
pits. A fine spreaderjet is used; rain-sprinklers are also employed with
a fine spray. The communal cow-sheds are situated adjacent to the humus
factory and are 50 by 15 feet each and can accommodate 200 head of
cattle: the enclosure, 173 by 57 feet, is also used to provide outside
sleeping accommodation; there is a water trough 11 feet 6 inches long by
3 feet wide to provide water for the animals at all times; the living
houses of the cowherds are near to the site. An office, store, and
chowkidar's house are in the factory enclosure. The main cart-road to
the lines runs parallel with the enclosure and during the cold weather
all traffic to and from the lines passes over this road, where material
that requires to be broken down is laid and changed daily as required.
Water for the factory has a good head and is plentiful, the main cock
for the supply being controlled from the office on the site. All pits
are numbered, and records of material used in each pit are kept,
including cost; turning dates and costs, temperatures, watering and
lifting, etc., are kept in detail; weighments are only taken when the
humus is applied so as to ascertain tasks and tons per acre of
application to mature tea, nurseries, tung berees, seed-bearing bushes,
or weak plants.

The communal cow-sheds and enclosure are bedded with jungle and this is
removed as required for the charging of the pits. I have tried out pits
with brick vents, but I consider that a few hollow bamboos placed in the
pits give a better aeration and these vents make it possible to increase
the output per pit, as the fermenting mass can be made 4 to 5 feet deep.
Much care has to be taken at the charging of the pits so that no
trampling takes place and a large board across the pits saves the
coolies from pressing down the material when charging. At the first turn
all woody material that has not broken down by carts passing over it is
chopped up by a sharp hoe, thus ensuring that full fermentation may act,
and fungous growth is general.


PLATE XI: Above, Covered and uncovered pits. Middle, Roofing a pit.
Below, Cutting Ageratum.


With the arrangement of the humus factory compost can be made at any
time of the year, the normal process taking about three months. With the
central factory much better supervision can be given, and a better class
of humus is made. That made outside and alongside the raw material and
left for the rains to break down acts quite well, but the finished
product is not nearly so good. It therefore pays to cut and wither the
material and transport it to the central factory as far as possible.

In the cold weather, a great deal of sheet-composting can be done. After
pruning, the humus is spread at 5 tons to the acre; and hoed in with the
prunings; the bulk of prunings varies, but on some sections up to 16
tons per acre have been hoed in with the humus and excellent results are
being obtained.

On many gardens the supply of available cow-dung manure and green
material is nothing like equal to the demand. Many agriculturists try to
make up the shortage by such expedients as hoeing-in of green crops and
the use of shade trees or any decaying vegetable material that may be
obtainable; on practically all gardens some use is made of all forms of
organic materials, and fertility is kept up by these means. It is
significant to note that, for many years now, manufacturers who
specialize in compound manures usually make a range of special
fertilizers that contain an appreciable percentage of humus. The
importance of supplying soils with the humus they need is obvious. I
have not space to consider the important question of facilitating the
work of the soil-bacteria, but it has to be acknowledged that a supply
of available humus is essential to their well-being and beneficial
activities.

Without the beneficial soil-bacteria there could be no growth, and it
follows that, however correctly we may use chemical fertilizers
according to some theoretical standard, if there is not in the soil a
supply of available humus, there will be disappointing crops, weak
bushes, blighted and diseased frames. Also it will be to the good if
every means whereby humus can be supplied to the soil in a practical and
economical way can receive the sympathetic attention of those who at the
present time mould agricultural opinion.

To the above must be added the aeration of the soil by drainage and
shade, and I am afraid that many planters and estates do not under stand
this most important operation in the cultivation of tea. To maintain the
fertility we must have good drainage, shade trees, tillage of various
descriptions, and manuring. Compost is essential, artificials are a
tonic, while humus is a food and goes to capital account.

This has been most marked in the season just closing. From October I 938
to April 20th, 1939, there had been less than 1-1/2 inches of rain, and
consequently the gardens that suffered most from drought were those that
had little store of organic material--drainage, feeding of the soil, and
establishment of shade trees being at fault.

Coolies are allowed to keep their own animals, which graze free on the
Company's land, and the following census gives an idea of what is on the
property: 133 buffaloes, 115 bullocks, 612 cows, 466 calves, 21 ponies,
384 goats, 64 pigs: in all, 1,795 animals.

During the past two years practically no chemical manure or sprays for
disease and pest-control have been used, the output for the past year of
humus was about 3,085 tons, while a further 1,270 tons of forest
leaf-mould have been applied. The cost of making and applying the former
is Rs.2/8/6 per ton, and cost and applying forest leaf-mould is RS.1/3/9
per ton

The conversion of vegetable and animal waste into humus has been
followed by a definite improvement in soil-fertility.

The return to the soil of all organic waste in a natural cycle is
considered by many scientists to be the mode of obtaining the
best-tasting tea, and to resisting pest and disease.

Nature's way, they claim, is still the best way.

GANDRAPARA TEA ESTATE,
BANARHAT, P.O.
J.C. WATSON.
18 November, 1939.




APPENDIX B



COMPOST MAKING AT CHIPOLI, SOUTHERN RHODESIA


Compost of a kind has been made at Chipoli for a number of years, but
till Sir Albert Howard's methods were mastered some years ago the waste
of material had been considerable, the product unsatisfactory, and the
cost, in comparison with that now produced, high.

Deep pits were used and the process was chicfly carried out under
anaerobic conditions, with the result that it took many months and most
of the nitrogen was lost. Farm-yard manure was stored either in the
stockyards or in large solid heaps, with the result that when the mass
was broken up to be carted on to the fields most of the nitrogen had
been lost, and much of the coarse grass, reeds, and similar matter used
for bedding remained fairly well preserved, much as bog oak in the mud,
and the process of decomposition remained to be completed in the soil
with the growing crop, much to the detriment of the latter.

At Chipoli the compost-field has been laid out on the same principle as
at Indore. Water is laid on and standpipes are situated at regular
intervals. One-inch rubber hose-pipes are used to spray the water on to
the compost heaps. With this arrangement compost can be made at any time
of the year, the normal process taking almost exactly three months.

It has been claimed that it is cheaper to make compost in heaps
alongside the lands where the raw material is grown and to rely on the
rains for the water. If the rains are regular this acts quite well; but
this is not always the case, and with the interruption of the process
the finished product is not so good. Another objection to making compost
away from an artificial water-supply is that the material to be
composted cannot be used the same season, with the result that a year is
lost. I have known seasons when the sequence of the rainfall has been
unsuitable for the completion of the manufacture, with the result that
the position of a farmer who had been relying on this method for the
provision of compost to maintain the fertility of his lands would be
serious. The cost of a water-supply is a small insurance premium to pay
for certainty of manufacture.

I find pits unnecessary even in the hot weather. If the heaps are
sprayed over every day it is quite enough to maintain the correct degree
of moisture, and one native can easily control 500 tons. To apply water
in buckets is not satisfactory: the material does not get a uniform
wetting--too much is thrown on one place and too little on another.

As the heaps are being turned, a controlled spray keeps the moisture
content correct.

The question of cost is raised against the central manufactory. I am of
opinion that the small extra cost of transportation is far more than
offset by better supervision and the control of the process. The cost of
moving the raw material can be reduced by stacking the san hemp, or
whatever is being used, in heaps, and allowing it to rot to a certain
extent. This considerably reduces the bulk.

The material used for making compost at Chipoli is mostly coarse velt
grass which is cut from river banks, dongas, and wherever it is
available; next in bulk is san hemp grown for the purpose, and then
rushes, crop wastes, weeds, garden refuse, and so forth.

Compost is returned to the san hemp stubble and the land then ploughed.
In the past large quantities of san hemp have been ploughed into the
land to maintain the humus supply. In some seasons this works quite
well, but in others, owing to unfavourable weather conditions,
quantities of unrotted vegetable matter are left on or under the
surface, to be decomposed the following season before a crop can be
planted. By cutting and composting this surface growth and returning it
to the land, everything is ready for planting as soon as the rains
commence. Again, compost made from combined animal and vegetable waste
has evidently some great advantage over humus derived from the top
growth of a green crop only.

In making the heaps, a layer of vegetable waste is put down; the heaps
are built about 25 yards long and 15 feet wide. Dung and urine-saturated
bedding is then laid on top and on this is spread the correct quantity
of soil and wood-ash; the whole is then wetted from the hose-pipe and
the process repeated till the heap is some 3 feet high. Heating
commences at once, and after some ten days, when fungous growth has
become general, the heap is turned and more water applied if required.
Two heaps are made side by side and if the bulk has become reduced
considerably, as generally happens by the time the third turning is due,
the two heaps are thrown into one. This maintains the bulk and so
ensures that the process goes on properly without any interruption.
Should action appear slow at the first turning, compost from another
heap--which is being turned for the second time and in which action has
been normal--is scattered among the material as it is being turned;
inoculation thus takes place and the process starts up as it should.

I have found that a mixture of grass and san hemp acts much better than
either san hemp or grass alone.

It has been the practice to lay coarse material on the roads and to
allow wagon traffic to pass over it for some time; this breaks it down
and action is much more satisfactory when manufacture commences. A
better plan is to pass all the raw material through the stock-yards,
where it becomes impregnated with urine and dung and gets broken up at
the same time by being trampled. All that is then necessary in making
the heaps is to mix this material with soil and wood-ash and moisten it.

It has always been the routine to broadcast some form of phosphatic
fertilizer on the lands. This is now added direct to the compost heaps
and so reaches the fields when the compost is being spread. The cheapest
form of manure to be bought locally is bone-meal; besides phosphate this
contains about 4 per cent. of nitrogen. Dried grass, the chief source of
raw material, contains about one-half per cent. of nitrogen; this is
very low, so that the addition of the extra nitrogen in the bone-meal
assists the manufacture, and none of the nitrogen is lost. This addition
of bone-meal is simply a local variation and is in no way necessary for
the working of the process.

This year a spell of very wet weather converted the open cattle-yards
into a quagmire. As soon as possible the sodden bedding and manure was
carted on to the compost field and built into heaps with a liberal
interbedding of soil. The material was so sodden that it packed tightly
and a dark-coloured liquid exuded from the heaps. The material was
turned immediately and more soil added, which absorbed the free liquid.
After an interval of three days, a further turning took place and with
this the swarms of flies, which had followed the manure from the yards,
disappeared. Heating was slow, so a further turn was given; at each turn
the heaps became more porous; with this last turn, heating became rapid
and the fungous growth started, normal compost manufacture having
commenced. Now that the principle of turning with the consequent
aeration is understood, losses which took place in the past through
improper storage will be avoided. One is reminded of the family midden
in countries like Belgium, with their offensive smells and clouds of
flies; if the composting principle was understood, what loss could be
avoided and how much more sanitary would conditions become!

The chief inquiry with many people before commencing compost making is
that of cost. This largely depends on local conditions. Labour costs and
the ease with which the raw materials can be collected are the chief
factors. I happen to grow tobacco and to use wood as fuel for curing; my
tobacco barns are close to the compost field so that my supply of
wood-ash is both plentiful and handy. The stock-yards are situated close
at hand, through which in future it is hoped to pass all the vegetable
wastes. It has been found that san hemp hay makes an excellent stock
food; stacks of this will be made alongside the compost field and
feeding pens put up where the working oxen can get a daily ration, the
refuse being put on to the heaps.

Compost making has been going on for too short a time here to be able to
give definite costs. A particular operation that costs a certain sum
this year may have its cost halved next year as methods of working are
improved. As an approximate indication, however, the following will
serve.

On a basis of turning out 1,000 tons of finished compost, collecting all
the raw material and spreading the compost on the field.

For those who do not know, a South African wagon is generally 18 feet
long; it is drawn by a span of sixteen oxen and holds a normal load of 5
tons. For carting vegetable wastes I make a framework of gum poles which
sits on the top of the wagon and so greatly increases its carrying power
for bulky materials. Sometimes two or three such wagons work on compost
making the same day, and sometimes not any, but an average would be one
wagon full time for four months. Such a wagon requires a driver and a
leader and two other men for loading and unloading with the help of the
driver and sometimes the leader. Labour for cutting and collecting the
coarse grass, reeds, etc., works out at about ten natives every day for
two months. The san hemp is cut with a mowing-machine and collected with
a sweep, say four natives for one month. As regards the manufacture
itself, four natives for five months can attend to everything. This
gives a total of 1,800 native days. For spreading the finished compost
some people use a manure-spreader, which does an excellent job, but such
an implement would be too slow for us.


PLATE XIII: Compost Making at Chipoli, Southern Rhodesia
Above, General view of composting area.
Below, Watering the heaps.

On Chipoli three wagons are used for spreading at the same time; each
wagon carries something over 3 tons of finished compost. Four natives
fill the wagons at the heaps and as soon as a wagon arrives in the field
it is boarded by four other natives with shovels or forks who spread the
compost on a strip of predetermined width as the wagon moves slowly
along. On an average, taking adjacent and more remote lands, one wagon
makes eight trips a day; thus with a total of fourteen natives we spread
some 75 tons of compost a day. Spreading 1,000 tons thus takes 200
native days. In other words, the whole operation from cutting the waste
materials to spreading the finished product on the land takes 2,000
native days. This means that the work of two natives for one day is
required for each ton of compost made and spread on the land.

To the above must, of course, be added the upkeep and depreciation on
wagons, mowing-machine, etc., when engaged on this work, but this is
quite a small item. The ox is not taken into account, as not only does
he assist in the manufacture by providing waste material, but when his
term of service has come to an end he is fattened up and sold to the
butcher, generally for a sum at least as much as he cost.

My water service, made from material purchased from an old mine, was
written off after the first season.

I made the statement recently before the Natural Resources Commission
that, if compost making became general in Southern Rhodesia, the
agricultural output of the country could be doubled without any more new
land being brought under cultivation.

Last year the bill for artificials on Chipoli was roughly half of what
it used to be, and if the state of the growing crops is any indication
the out-turn will increase by fifty per cent.

This season compost has been used on citrus, maize, tobacco, monkey
nuts, and potatoes. A neighbour was persuaded, somewhat against his
will, to make some compost; this he did and applied it to land on which
he planted tobacco: he now tells me that that particular tobacco was
much the best on his farm.

Some photographs published in the Rhodesia Agricultural Journal show in
a striking manner the drought-resisting properties imparted to land
after being dressed with compost. The maize plants on the land to which
compost had been added show almost no signs of distress, while those
alongside on land that had no compost are all shrivelled up. Properly
made compost has the property of fixing a certain amount of atmospheric
nitrogen. To do this to the best advantage it appears necessary that the
manufacture should be carried out as quickly as possible. There must be
no interruption, and the material must on no account be allowed to dry
out or to become too wet. I am inclined to use more soil than is
absolutely necessary; it costs nothing, and the small extra charge in
transport is more than covered by its presence as a form of insurance
against any nitrogen that might be given off' which it tends to grasp
and fix. We at the present stage know little about mycorrhiza, but it is
probable that an excess of soil is not a disadvantage where this is
concerned.

Where the acreage is large and the compost will not go round it all, it
is probably better to give a medium dressing to a larger acreage than a
heavy dressing to a smaller one. A dressing of about 5 tons to the acre
is about the minimum for ordinary crops, but for such things as potatoes
and truck crops at least 10 tons to the acre should be given, and, if
available, considerably more. It must be borne in mind that much of the
soil in Rhodesia has been so depleted of humus that in order to bring it
properly to life again much heavier dressings of compost will be
necessary now than when it has once attained natural conditions.

The more I see of compost-making the more necessary it appears to be to
let the material have continuous access to air. This, as has been
previously explained, can be done by frequent turning, and if turned
quickly very little heat need be lost and no interruption in the process
takes place.

An advance to better air-supply would be a series of brick flues under
the heaps. But under my conditions, with the position of the heaps
continually changing and with Scotch carts and heavy wagons continually
moving among the heaps, the flues would always be getting broken.
Six-inch pipes with slots cut in the sides and the piece of metal from
the slot hinged on one side and turned outwards on each side so as to
form an air-space in the compost, with a continual supply of air from
inside the pipe, would probably act quite well, the advantage being that
such pipes would be portable and would be laid down just before the heap
was about to be built. The disadvantage is, of course, one of cost. To
go even farther, a small oil-driven compressor, such as is used to drive
a pneumatic hammer, and mounted on a wheelbarrow or small hand-truck and
connected to a pipe by rubber hose, could be used. The pipe would be,
say, 1 inch in diameter and pointed at one end. For a distance of
perhaps 18 inches from the point small holes would be drilled. The pipe
would be pushed into the heap at the centre and air pumped in, the
operation being repeated at perhaps distances of 3 feet. A large number
of heaps could be treated with forced aeration in a day, and if this
method resulted in the fixation of only a few extra pounds of nitrogen
per ton it might be well worth while.

This is, however, perhaps going too far at the present stage. The great
beauty of Sir Albert Howard's method is its simplicity. It can be used
in native villages by primitive people using their own tools equally
well as on the most up-to-date estates using elaborate machinery.

I am glad to say that the Rhodesian Government have laid it down that
compost-making is to be taught at all native agricultural instructional
centres. Interest in the matter will gradually awaken. I have already
had old men from neighbouring villages come in to see how manure was
made from dry grass.

We are on the eve of the compost era. Had its principles been applied
years ago, the desolation that has taken place in the Middle Western
States of America could have been avoided. The so-called 'law of
diminishing returns' is seen to apply only to those who do not really
understand the soil and treat it as Nature meant it to be treated.
Rhodesia is fortunately a young country and the destruction of its soil
has not gone very far, comparatively speaking.

If compost making becomes general, which means thorough rebuilding of
the soil and so providing it with greater fertility, greater power to
withstand droughts through its enhanced ability to absorb the rainfall,
much of which now runs needlessly to the ocean, a great change in the
agricultural outlook will take place. The present system, employed by
many, of mining instead of farming the soil, of stimulating it to the
last extent with artificials, and--when it has been killed--abandoning
it, must be exchanged for real soil-building according to Nature's
methods. Only in this way can disaster, examples of which can be seen
all round, be avoided, and the land be made to produce what it was
intended to produce before our too clever methods were employed upon it.

J. M. MOUBRAY
CHIPOLI SHAMVA,
SOUTHERN RHODESIA
2 February 1939.




APPENDIX C



THE MANUFACTURE OF HUMUS FROM THE WASTES OF THE TOWN AND THE VILLAGE
By SIR ALBERT HOWARD, C.I.E., M.A.,
Formerly Director of the Institute of Plant Industry,
Indore, Central India, and Agricultural
Adviser to Slates in Central India and Rajputana.


The forest suggests the basic principle underlying the correct disposal
of town and village wastes in the tropics. The residues of the trees and
of the animal life, met with in all woodlands, become mixed on the floor
of the forest, and are converted into humus through the agency of fungi
and bacteria. The process is sanitary throughout and there is no
nuisance of any kind. Nature's method of dealing with forest wastes is
to convert them into an essential manure for the trees by means of
continuous oxidation. The manufacture of humus from agricultural and
urban wastes by the Indore Process depends on the same principle--an
adequate supply of oxygen throughout the conversion.


THE INDORE PROCESS

The Indore Process, originally devised for the manufacture of humus from
the waste products of agriculture, has provided a simple solution for
the sanitary disposal of night soil and town wastes. The method is a
composting process. All interested in tropical hygiene will find a
detailed account of the big-chemical principles underlying the Indore
Process, and of the practical working of the method, in the five papers
cited at the end of this note.


HUMUS MANUFACTURE AT TOLLYGUNGE, CALCUTTA

Perhaps the best way of introducing the application of the Indore
Process to town wastes will be to give an account of the recent work
done by Mr. E. F. Watson, O.B.E., at the Tollygunge Municipality
trenching ground, near Calcutta.

The conversion of house refuse and night soil into humus is carried out
in brick-lined pits, 2 feet deep, the edges of which are protected by a
brick kerb. The guard rim is made of two bricks laid flat in cement
mortar, two quarter-inch rods in the join serving as reinforcement. The
upper brick should project 1 inch over the pit to form a lip for
preventing the escape of fly larvae. Each compartment of the pit has a
capacity of 500 cubic feet and channels for aeration and drainage are
made in the floor. The aeration channels are covered with bricks laid
open-jointed, and are carried up at the ends into chimneys open to the
wind. By this means air permeates the fermenting mass from below. At one
point these channels are continued as a drain to the nearest low-lying
land. It is an advantage when bricking the pits to give a slight slope
towards the aeration channels as this helps in keeping the pits dry in
wet weather. The area round the pit is protected by brick soling.
Working details of these composting pits are shown in Fig. I.

The method of charging the pits is most important, as success depends on
correct procedure at this point. To begin with, a cartload of unsorted
refuse is tipped into the pit from the charging platform and spread by
drag rakes (Fig. 9) to make a layer 3 or 4 inches thick. Another
cartload of refuse is then tipped on this layer and raked into a slope
reaching from the edge to the middle of the pit and occupying its whole
width. The surface of this slope is slightly hollowed by raking a little
refuse from the centre to the sides. A little refuse is also raked on to
the sill at the road edge to receive any night soil spilt on it by
tipping. Half a cartload of night soil is then tipped on the slope and
with the moistened refuse below it is drawn by drag-rakes in small lots
until the breadth of the pit is covered. This done, the remaining
half-load of night soil is poured on the freshly exposed surface of the
slope and distribution by raking repeated until the slope (and the
refuse on the sill) is altogether removed and forms a layer over the
whole of the pit being charged. Another cartload of refuse is then
tipped, another slope made, the sill covered, night soil added and raked
away. The whole group of operations is so repeated until the pit is
charged. This takes 2 days. The top layer of the first day's charge must
be covered with 2 inches of refuse and left unmixed with the layer
below. This helps to keep uniform moisture and heat in the mixed charge
and to prevent the access of flies. The last operation on the second day
is to make a vacant space at the end of each pit for subsequent turning
and also for assisting drainage after heavy rains. This is done by
drawing up 2 feet of the contents at one end over the rest. The surface
is then raked level and covered with a thin layer of dry house refuse.

There is no odour from a pit properly filled, because the copious
aeration effectively suppresses all nuisance. Smell, therefore, can be
made use of in the practical control of the work; if there is any
nuisance the staff employed is not doing the charging properly. They are
either leaving pockets of night soil or else definite layers of this
material, both of which interfere with aeration and so produce smell.

First Turn.--Five days from the start the contents of the pit must be
turned. The object of this turn is to complete the mixing and to turn
into the middle, and so destroy the fly larvae which have been forced to
the cooler surfaces by the heat of the mass.

The original mixing of the heap, as well as the turning, are best done
with long-handled manure drags by men standing on the division walls or
on a rough plank spanning them.

Second Turn. After a further ten days the mass is turned a second time,
by which time all trace of night soil will have disappeared.

Watering. In dry weather it may be necessary to sprinkle a little water
on the refuse at each turn. The contents must be kept damp but not wet.

In very wet weather, when the surface of the pits is kept continually
cool by rain, there is much development of fly larvae before the first
turn, but since these cannot escape and are turned into the hot mass and
destroyed before they can emerge as flies, no nuisance results. Flies,
therefore, are most useful in providing another means of automatic
control.

Ripening of the Compost. After a further two weeks the material is
removed from the pits to the platform for ripening. The whole process,
therefore, takes one month. The stacks of ripening compost should be 4
feet high, arranged clear of the loading platform on a stacking ground
running between two lines of pits (Fig. 10). The stacking process
permits of sorting. Any material not sufficiently broken down, such as
sticks, leather, coco-nut husks, and tin cans are picked out and thrown
into an adjacent pit for further treatment. Inert materials such as
brickbats and potsherds are thrown on the roads for metalling.
Hand-picking is easy at this stage, as the contents of the pit have been
converted into a rough, inoffensive compost. The ripening process is
completed in one month, when the humus can be used either for manuring
vacant land or as a top dressing for growing crops.

Cost. The capital cost is very small. A population of 5,000 in India
yields some 250 cubic feet of house refuse daily, enough to mix with all
the night soil. This will require a compost factory of sixteen pits of
500 cubic feet each, one pit being filled in two days (Fig. 10). With
roads, platforms, and tools this costs from Rs. 1,000 to Rs. 1,500. The
daily output is 150 cubic feet of finished compost, which finds a ready
sale at Rs. 5 to Rs. 7. At the lower figure the sale proceeds of the
first year will be about Rs. 1,800. This more than covers the working
expenses. A factory of this size will need a permanent staff of five
men.


A SIMPLE INSTALLATION FOR A VILLAGE

When a rural community is too poor to own conservancy carts or to
construct brick-lined pits, composting can be carried out in an open
trench on any high ground, without the use of partition walls.

The difficulty with unlined pits is the escape of fly larvae which breed
in the walls of the trench and in the stacks of ripening compost. This
disadvantage can be overcome either by bricking the vertical walls or by
keeping fowls, which thrive on the larvae.


SOME FURTHER DEVELOPMENTS

The Use of Humus in Collecting Night Soil. There is one weak point in
these two applications of the Indore Process to urban wastes. In both
cases night soil is collected, transported, and composted in the crude
state. This gives time for putrefaction to begin and for nuisance to
develop. It can be prevented by the use of humus in the latrine pails,
which ensures the oxidation of the night soil from the moment of
deposition, and so prevents nuisance and the breeding of flies. The
pails should contain at least 3 inches of dry humus when brought into
use each day, and the droppings should be covered with a similar layer
of humus when the pails are emptied into the conservancy carts. In this
way putrefaction and smell will be avoided; the composting process will
start in the pails themselves. The use of humus will augment the volume
and weight of the night soil handled, but this increase in the work will
be offset by the greater efficiency of composting, by the suppression of
smell and flies, and by a considerable reduction in the loss of combined
nitrogen.

Composting Night Soil and town Wastes in Small Pits. Night soil can be
composted in small pits without the labour of turning. These pits can be
of any convenient size, such as 2 feet by 12 feet and 9 inches deep, and
can be dug in lines (separated by a foot of undisturbed soil) in any
area devoted to vegetables or crops. Into the floor of the pits a fork
is driven deeply and worked from side to side to aerate the subsoil and
to provide for drainage after heavy rain. The pits are then one-third
filled with town or vegetable waste, or a mixture of both, and then
covered with a thin layer of night soil and compost from the latrine
pails. The pit is then nearly filled with more waste, after which the
pit is topped up with a 3-inch layer of loose soil. The pit now becomes
a small composting chamber, in which the wastes and night soil are
rapidly converted into humus without any more attention. After three or
four months the pits will be full of finished compost and alive with
earthworms. A mixed crop of maize and some pulse like the pigeon pea
(Cajanus indicus) can then be sown on the rows of pits as the rainfall
permits, and gradually earthed up with the surplus soil. The maize will
ripen first, leaving the land in pigeon pea. The next year the pits can
be repeated in the vacant spaces between the lines of pulse. In two
seasons soil fit for vegetables can be prepared.

Reprinted from a paper read at the Health Congress at the Royal Sanitary
Institute held at Portsmouth from July 11th to 16th, 1938.


LITERATURE

HOWARD, A., and WAD, Y. D. The Waste Products of Agriculture: Their
Utilization as Humus. Oxford University Press, 193 I.

JACKSON, F. K., and WAD, Y. D. 'The sanitary Disposal and Agricultural
Utilization of Habitation Wastes by the Indore Method', Indian Medical
Gazette, lxix, February 1934.

HOWARD, A. 'The Manufacture of Humus by the Indore Method', Journal of
the Royal Society of Arts, November 22nd, 1935, and December 18th, 1936.
(These papers have been reprinted in pamphlet form and copies can be
obtained from The Secretary, Royal Society of Arts, John Street,
Adelphi, W.C. 2.)

WATSON, E. F. 'A Boon to Smaller Municipalities: The Disposal of House
Refuse and Night Soil by the Indore Method', The Commercial and
Technical Journal, Calcutta, October 1936. (This paper is now out of
print, but the substance has been incorporated in a lecture by Sir
Albert Howard to the Ross Institute of Tropical Hygiene on June 17th,
1937. Copies can be obtained on application to the lecturer at I4
Liskeard Gardens, Blackheath, S.E. 3.)

HOWARD, A. 'Soil Fertility, Nutrition and Health', Chemistry and
Industry, vol. lvi, no. 52, December 25th, 1937.



THE END





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