The Work on the lndore Process
As long ago as 1893 Dr. J. A. Voelcker in a notable Memorandum addressed to the Government of India (reprinted in part in the journal now issued by the Ministry of Agriculture of the Government of India as the Compost Bulletin, Vol. II, No. 3, Sept. 1949, Appendix B) laid stress on the misuse by the population of animal manure. Not only was no effort being made to grow timber for fuel to replace the burning of cow-dung, but even the residue that was left after so much had been necessarily used in this way was never properly prepared to go on the land and all the valuable urine was lost. Thirty years later Sir Albert Howard deplored an equal indifference in regard to the preparation of vegetable wastes; assuming that there was no choice but to use most of the animal excrement for domestic purposes, there was no excuse for the neglect of vegetable residues for purposes of soil enrichment.
'The statement constantly reiterated that the soil of India cannot be adequately manured, on account of the utilization of so much of the cow-dung for fuel, is only partially true. There is a vast mass of vegetable refuse which, if properly treated, will produce a large proportion of the organic matter and the combined nitrogen which the soils of India require. Most of this vegetable refuse is at present wasted or is misused. It is not uncommon to see dried leaves, stalks and other vegetable refuse burnt by the municipalities to save the expense of removal. Villagers often burn the refuse on the fields or at best put it back into the land in an unfermented condition. It is a distressing sight to see India's potential wealth going up in smoke and moreover in ineffective smoke. The use of cow-dung as fuel for cooking has certain advantages, from the point of view of preparing food, but the misuse of vegetable refuse has none.'
As Sir Albert says, it was a tradition to assume that the soils of India could not be manured with enough animal dung; the problem was an old one. The additional evil of the misuse of vegetable matter which might have been saved was more or less ignored. The result of both forms of neglect appeared glaringly in a scale of food production which spelt year-long hunger and poverty.
Such were the conditions into which the Western scientists at Pusa and in the Provinces intruded with their energetic programmes for raising production. Their suggestions were vigorous; better tools, more irrigation, better agricultural methods, wide seed distribution, but above all improved varieties of crops to give heavier harvests; here was an uncharted field, golden opportunities. There followed a massive output of Experiment Station results in plant breeding, all of which could with advantage be applied to Indian agriculture.
It was some years before the question was asked where this would lead. But the very success of the Pusa wheat experiments, for which he himself had been responsible, as well as those on tobacco and indigo, began to raise doubts in Sir Albert's mind as to whether the Indian soils in their prevailing condition would be able to stand the strain. A great deal more was now being taken out of them: was the corresponding amount being put back? Was not the old manurial problem being intensified, possibly with disastrous results?
The final solution of this ancient problem was only arrived at towards the end of Sir Albert's career in India. There was a gradual development of practice and theory. From the outset stress was laid on the need for organic matter. In default of sufficient animal dung the obvious source was green-manure. Great attention was therefore paid to this question and there are constant references to green-manuring in the early papers; as we have seen, Sir Albert deplored any burning of green wastes. Their use to enrich the soil was constantly advocated and practically no crop was raised without this accompaniment when required. Green-manuring, like proper drainage, became welded into the daily practice at Pusa, and the years of experience gained formed the later basis for an outstanding section in An Agricultural Testament, where the principles governing the use and misuse of a green-manure are set forth with great force and clarity. (An Agricultural Testament, pp. 87-95.) This work has been referred to in a previous chapter, and need not be further described here.
But while concentrating for a long period on this, the first step in a method for regenerating the soils of India, another and more crucial idea was gradually being absorbed. The numerous journeys which Sir Albert undertook over India, into Baluchistan and Kashmir, Sikhim and Nepal, and into Ceylon, here bore their fruit, for in the course of these one lesson was ever insistent. If agriculture in the broad countryside was only extensive and crops were much as might be expected from soils in an average condition, growth round the villages, where human excrement was daily deposited, was infinitely richer. These belts of vegetation always stood out. As Sir Albert says, India offered a series of 100,000 experimental plots which were plain to the eye.
'The urgent need for more nutrifiable organic matter in the black soils is at once evident when we compare the growth of the cotton plant on the rich fields near a village with that on outlying areas which, in Central India and Rajputana, are seldom or never manured. The addition of fermented organic matter leads to rapid growth, to larger plants, to a much higher yield of seed-cotton and to a crop which is able to withstand the heavy rainfall which so often checks the cotton plant on poor soils. No experiments are needed to demonstrate the effectiveness of more organic matter for cotton and other crops. No mathematical formulae and no replication of small plots are required to bring the results home to the people. This work has already been done, the whole countryside demonstrates the results.'
The solution of the manurial problem of India was thus to be found in the combination of animal and vegetable wastes. Yet India herself, in spite of her 100,000 'experiments', could not provide the final formula of success.
The Summing-up of Previous Investigations
In describing the work which he accomplished in solving this great and serious problem Sir Albert Howard used a telling simile; all the materials for dealing with it, he said, were lying about in a builder's yard, but the building was lacking. He was referring to the many investigations, some going back almost a century, on the different aspects which constitute the general problem of soil fertility: the preparation and conservation of animal manure, the preparation of 'artificial' farmyard manures, the use of mineral artificial fertilizers, the enquiry into the yields of soils not manured at all, the role of the leguminous crop, and the principles of green-manuring in general. In these investigations the importance of organic matter and the exact way in which it contributed to soil fertility was as yet but little understood.
The holding of a Symposium on Soil Organic Matter and Green-manuring at Washington in the U.S.A. in November 1928 was a landmark, but Sir Albert noted that even the principal speaker, S. A. Waksman, contributed not one, but three different papers dealing with what were considered to be separate subjects, farmyard manure, green-manure, and artificial farmyard manure. Humus as the general clue to all these matters began to emerge slowly, partly as the result of Waksman's writings, which greatly influenced Sir Albert and which he always considered as forming the basis for future investigation. (Waksman's great book, Humus, did not appear until 1936, five years after the publication of The Waste Products of Agriculture, but his numerous previous papers gave the results of his extensive experiments.) Waksman's work was founded on lifelong laboratory experiments; he was a pioneer in a new field. Sir Albert's work was of a different nature, also based on experiment, but carried out in the field, though laboratory technique was used as required. It was thus quite appropriate that, in addition to Waksman's writings, Sir Albert should have been simultaneously influenced by a very different writer, F. H. King, who in his classic Farmers of Forty Centuries, gave a detailed and extraordinarily interesting description of the methods in use for centuries past in China, Korea and Japan for conserving soil fertility.
In addition, much other literature had been studied on soil problems, including the records of the great Experiment Stations such as Rothamsted. (There was also the work on composting of Dr. Gilbert Fowler at Cawnpore.) When therefore Sir Albert eventually summarized the question in his book, The Waste Products of Agriculture: their Utilization as Humus (O.U.P., 1931) he had a great deal to say. At the risk of being a little discursive, I propose to give here the more important points of his summary.
The first source of organic matter in the soil is the root of the crop. When the crop is reaped, the roots are left behind; they decay and form humus. It is possible, with careful cultivation, to continue on this basis for a long time with no other addition of organic matter. This is known from the Broadbalk experiment at Rothamsted, where wheat has been grown on the same land without manure since 1844; over the first eighteen years there was a slow decline, since when the yield has been practically constant at a rather low level. A more striking example, cited by Sir Albert, was the very old system found on the alluvial soils of the United Provinces, where the field records of no less than ten centuries prove that the land produces fair crops year after year without manure and with no falling off in fertility, a perfect balance having been reached between the requirements of the crops harvested and the natural processes which recuperate the soil. (The Waste Products of Agriculture, p. 38.) While the Rothamsted work is mentioned by Sir Albert as the recognized European record of the principles involved (the important point that fresh seed was brought in every year to sow the Rothamsted field was not public knowledge until much later), yet Eastern experience provided an example on so much vaster a scale and continued over so much longer a period that it cannot be counted as surprising if once again Sir Albert was led to state that Eastern peasant agriculture could provide him with all the 'experiments' he needed.
If, however, something more is aimed at than this base-line level of soil fertility, some replenishment of the soil is needed; organic matter must be added. The oldest system, and it is very old indeed, we do not know how old, is to add some form of animal excrement, dung or urine. The experience of all nations has endorsed the value of this principle. Yet Sir Albert notes how defective are the methods for preparing and for storing this valuable material. Even under the Western covered-yard system as much as 15 per cent of the nitrogen is lost. Reference is again made to Rothamsted experiments by Russell and Richards and their conclusion is endorsed that the best system would be to store manure in water-tight tanks or pits under anaerobic conditions. (There has lately been some confusion on the subject of anaerobic methods; these are to be advocated for the conservation of manure, not for the making of compost.) Reform in the management of the manure heap was a subject to which Sir Albert returned in later life.
Mention is then made of a new system only ten years old, also the work of Rothamsted, namely, the manufacture of 'artificial farmyard manure' out of straw and other vegetable material by means of the addition of a chemical activator -- the well-known ADCO process. Sir Albert was attracted by this work, to which he attributes importance, and gives full credit to the 'useful' and 'stimulating' quality of the investigation. Yet once again he is able to state that an Eastern nation, the Chinese, had to all intents and purposes done the same thing by mixing clover with rich canal mud, thus anticipating by many hundreds of years the findings of Western science. He justly adds that the Chinese practice would have passed for ever unheeded by us, while the effort of the scientist has made known to many a useful innovation. Synthetic farmyard manure was, in fact, at that time being prepared in India on Rothamsted principles in Madras, the Central Provinces, and Bengal. (Report of the Royal Commission on Agriculture in India, 1928, § 83.)
On the subject of actual artificials, i.e. substances of mineral content made in a factory, Sir Albert does not at this stage of his career say a great deal. They are by no means condemned, but there was no demand for them in Eastern agriculture. This question is referred to in more detail elsewhere. (See Chapter 3, The Supreme Importance of Air Supply to Crops, and Chapter 8, The Question of Statistics and Views on Artificial Fertilizers.)
There remained the possibilities of green-manuring. As already stated, Sir Albert had for years incorporated the use of green-manures into his cropping methods. This prolonged experience had taught him one definite lesson, the absolute necessity of not allowing a competition for nitrogen to arise between the decaying green wastes and any growing crop. The neglect to pay attention to this point accounted for the extraordinarily erratic results of much green-manuring practice. But these disappointments could be avoided provided that the green-manure was properly prepared beforehand for the use of the soil micro-organisms and the crop.
'Every scrap of vegetable refuse should be utilized as manure, but it is useless to apply it to the soil in a raw state as is so often the case. The pore-spaces of the black soils need a constant supply of finely divided, fermented organic matter, ready for nitrification, so that when the rains break no time is lost by the soil in preparing food materials for the crop. Time is perhaps the most important factor in the growth of monsoon crops on the black soils. Sowing must be carried out the moment there is sufficient moisture for the seed to germinate. The whole energies of the soil must then be used up in growing the crop. There must be no competition between the growth of the plant and the preparation of its food materials. Everything must be ready beforehand if maximum yields are to be obtained. Any delay is paid for by a greatly diminished yield.'
With the recognition of the need for preparing the green organic matter the problem was well on the way to a solution. It needed only the additional lesson of the belts of intensive cultivation round the Indian villages to drive it home, and to lead the investigator to the master principle of combining the use of prepared vegetable and animal wastes. Actual experiments were first begun in a desultory way, but finally very carefully systematized.
It is not on record how far actual experiments go back. Sir Albert Howard was accustomed to say that the Indore Process was the result of nearly thirty years' reflection, had required the services of three highly qualified scientists (Albert and Gabrielle Howard and Mr. Yeshwant Wad, to whom the chemical side of the enquiries were assigned) and had cost roundly £100,000 to perfect. In a paper contributed to the Symposium on the Nitrogen Problem in Indian Agriculture, held at the Indian Science Congress of 1923, there is a reference to experiments which had been in progress 'for some time' at Pusa with a view to working out some easy and practicable system for applying the Chinese-Japanese principles of composting to Indian conditions. (Proceedings [in part] of the Tenth Indian Science Congress, Lucknow, 1923. Published by the Asiatic Soc. of Bengal, Calcutta, 1924, p. 250.) The work must have been very fairly advanced, for there is already a brief discussion of the process and of the best methods and times of applying the finished product. In this direction success had been registered, for two years previously, in 1921, a first dressing of 'leaf compost on the Chinese system' to a field of lucerne had given an increase of 50 per cent, and a similar dressing in 1922 an increase of 70 per cent. (Cf. Chapter 4, Grass, Fodders, and Green Manuring, and The Improvement of Fodder.) Perhaps these results provided an unlooked-for initial encouragement. At any rate, on taking up the direction of the Indore Institute in 1924 systematic experiments were immediately started in such a way as to show that they must have been mentally planned some time before.
To judge the Process therefore as a mere empiric result, which any capable investigator could have completed, is wholly to underrate what was achieved. The very idea was highly original, for though Sir Albert in his writings makes frequent reference to Chinese principles and though, in any case, the making of leaf-mould in Europe and of some form of humus in indigenous agricultures all over the world has always been known, yet this particular combination of the clever Chinese practice (vastly improved by the skill which has ensured high pathogen-destroying temperatures) with such advanced Western scientific knowledge as has enabled us to apprehend the intricate bio-chemical and biological processes going on in the compost heap, was due to Sir Albert, and he alone can claim the honour of having introduced a practice which is revolutionizing world agriculture.
The work starts with emphasis on the all-important role of humus in the soil. For a description of this complex and difficult conglomeration of substances Sir Albert was accustomed to quote Waksman, whose careful definition seemed to him the best that could be given.
'The organic matter found in the soil consists of two very different classes of material: (1) the constituents of plants and animals which have been introduced into the soil and are undergoing decomposition; various unstable intermediate products which have been formed under certain environmental conditions; substances like lignified cellulose which are more resistant to decomposition and which may persist in the soil for some time; and (2) a number of valuable materials which have been synthesized by the numerous groups of micro-organisms which form the soil population. The soil organic matter is thus a heterogeneous mass of substances which is constantly undergoing changes in composition. When its composition reaches a certain stage of equilibrium, it becomes more or less homogeneous and is then incorporated into the soil as "humus".'
What is the role of this heterogeneous and variable combination of substances in promoting the growing of crops? In 1931 Sir Albert stressed three aspects and found this analysis so satisfactory that he maintained it in all his future writings.
'This material influences soil fertility in the following ways:
'1. The physical properties of humus exert a favourable influence on the tilth, moisture-retaining capacity and temperature of the soil as well as on the nature of the soil solution.
'2. The chemical properties of humus enable it to combine with the soil bases, and to interact with various salts. It thereby influences the general soil reaction, either acting directly as a weak organic acid or by combining with bases liberating the more highly dissociating organic acids.
'3. The biological properties of humus offer not only a habitat but also a source of energy, nitrogen and minerals for various micro-organisms.
'These properties -- physical, chemical and biological -- confer upon humus a place apart in the general work of the soil including crop production. It is not too much to say that this material provides the very basis of successful soil management and of agricultural practice.'
There is a great deal of attention paid to the chemistry of the compost heap throughout The Waste Products of Agriculture: at one point the compost maker is actually urged to become 'a chemical manufacturer' (see Chapter 2). Sir Albert could never have ignored the true importance of chemistry in agriculture: the fact that he engaged a first-class chemist to assist him in the compost experiments and associated Mr. Yeshwant Wad's name with his own as author of the resulting book shows how alive he was to the chemical aspects: the various analyses made in the course of the work bear this out, as will be shown hereafter. It is necessary to make this point because in later life Sir Albert had some very hard things to say about the chemist in agriculture, but these diatribes sprang from no contempt for chemical knowledge, but were a protest against the mistaken emphasis which gave exclusive priority to chemical analyses in a field where the principal influences are biological. In course of time Sir Albert came to the conclusion that for all practical purposes the chemistry of the compost heap could more or less be taken for granted. It was, in the first place, so immensely complicated that only a very delicate analysis could ever suffice to establish it; in the second place, it was progressive in that it altered from day to day and even from hour to hour; in the third place, it was quite unrepresentative of the real values inherent in compost, which could only be expressed in biological terms: to ascertain the exact amounts of nitrogen or other elements present in a compost heap at some passing given moment thus seemed singularly unrevealing. He therefore considered himself justified in rejecting judgments on the value of compost which were primarily based on chemical conception. He expressed this in a popular way by saying that 'every compost heap had its own history', by which he meant that every compost heap was a complex and dynamic aggregate of living organisms, the life and death of which was a part of the whole development of the universe and which could never be caught and reduced to static proportions with much approach to the truth. But that a great deal of careful work was done at Indore on the chemistry of compost will be clear from the description which follows.
After defining the three-fold aspect of the values of compost Sir Albert continues by laying down seven conditions for its making. It is remarkable that these seven conditions have needed no major modification, indeed, no modification whatever, from that day to this. They are clear, definite and altogether complete: they are practical and at the same time embrace the fundamental scientific points at stake.
They are here given in a shortened form.
'Any successful system of manufacturing compost must fulfil the following conditions:
'1. The labour required must be reduced to a minimum.
'2. A suitable and also a regular carbon-nitrogen ratio must be produced by well mixing the vegetable residues before going into the compost pits.
'3. The process must be rapid. To achieve this it must be aerobic throughout (the sentence ignores the point made very clearly elsewhere that the final processes may be anaerobic), and must include arrangements for an adequate supply of water and for inoculation at the right moment with the proper fungi and bacteria. (From old material -- see below -- not from patent inoculants or preparations; these had not been thought of at this stage and were later invariably condemned by Sir Albert.) The general reaction of the mass must be maintained, within the optimum range, by means of earth and wood ashes.
'4. There should be no losses of nitrogen at any stage; if possible, matters should be so arranged that fixation takes place in the compost factory itself and afterwards in the field.
'5. There must be no serious competition between the last stages of the decay of the compost and the work of the soil in growing a crop.
'6. The compost should not only add to the store of organic matter and provide combined nitrogen for the soil solution but should also stimulate the micro-organisms.
'7. The manufacture must be a cleanly and a sanitary process from the point of view both of man and also of his crops. There must be no smell at any stage; flies must not breed in the compost pits or in the earth under the work cattle.'
The final words of the above quotation indicate that the experiments at Indore were organized to suit Indian conditions; as always Sir Albert kept in mind the limitations imposed by peasant poverty. The implements used were throughout simple and of types already known to the population or improvised out of accessible materials. The spade, phawra, was a kind of scraping or hacking hoe as universally found in the East; measurement was by tagari, a sheet-iron bowl with capacity of five-sevenths of a cubic foot; material was carried in a pal or stretcher made of gunny-sheet nailed to two seven-foot bamboos; there was a simple wooden rake for charging pits, an ordinary wooden tub for slurry, and the well-known kerosene tin to carry water.
Demonstrations were, however, laid out on a 'factory' scale in thirty-three pits, each 30 ft. by 14 ft. by 2 ft., conveniently sited opposite the cattle shed and carefully arranged so as to allow carts not only to approach each pit but also to pass each other on the way. There was a water supply derived from a raised tank into which a week's supply was pumped, feeding eight stand-pipes so disposed that all pits could be hosed without difficulty; such a piped supply was strongly advocated by Sir Albert for similar large-scale work, though of course he did not dream of suggesting it as needed by the peasant, in whose case proximity to a well was all that was required. Eventually the 300 acres at Indore produced 1,000 cartloads of compost per year. The limiting factor was not animal, but vegetable wastes. The amount of animal wastes from forty draught oxen gave a large surplus, which could be used either directly as manure or as fuel for cooking. Towards this use of some manure for cooking Sir Albert remained sympathetic. He pointed out that the slow heat engendered was very suitable for the preparation of a vegetarian diet and did not advocate the substitution of another fuel. As each cartload of compost was equivalent, as regards nitrogen content, to two cartloads of ordinary farmyard manure, and taking other factors into consideration, had about three times the value of such manure, the fields of India could be supplied as required and yet leave enough material over to allow for the manufacture of the well-known kundas, cow-dung cakes for fuel. (The Royal Commission on Agriculture in India, which reported in 1928, was also rather inclined to accept the use of cow-dung for fuel as inevitable and specially suitable in India, at any rate until alternative forms of fuel could be grown. The whole of their Chapter on the Manurial Problem in India is reprinted as Appendix A in The Waste Products of Agriculture. The present Government of India has recently started an energetic campaign for the planting of trees to provide fuel so as to conserve the cow-dung for the land.)
Thus the experiments conformed both to traditional needs and to the orderly set-out demanded by science. Sir Albert always laid great stress on siting and arrangement in compost manufacture. Initial planning could save a vast amount of future labour, and the arrangements at Indore were carefully designed for this end; the abundance of labour available in India was thus as shrewdly husbanded as much more expensive labour might have been elsewhere. This led later to the general view that complaints of cost in compost making were usually the result of bad planning and poor management. (The latest figures in England are astonishingly low ; 1s. a ton at Goosegreen Farm, Somerset, without machinery, and 3s. a ton at Chantry, Wiltshire, using special machinery.)
One point which emerges is the very careful preparation of the raw materials. These were not just collected and thrown into the pits. Of the vegetable wastes -- and all were collected (See table below, The Composition of the Raw Materials; the composting of the water-hyacinth was later carried out separately at Indore, and was also investigated by Dr. Gilbert Fowler and later put into practice in Bengal by Mr. E. Fairlie Watson) -- the woody materials like cotton and pigeon-pea stalks were strewn on the Experiment Station roads to be trampled and broken up by the passing traffic; all green materials were withered for two days; and all material was stacked, layer by layer, near the composting site, when possible under shelter, to be removed in vertical slices so as to ensure an even mixture; refractory materials, such as sawdust or waste paper, were left to moisten under a little earth in an empty compost pit or even steeped in water for two days. Equal care was devoted to the preparation of the animal wastes. Earth from the silage pits, sweepings from the threshing floor, and all silt from drains were stored near the cattle shed; this was spread evenly on the cattle-shed floor, itself earthen, to a depth of six inches and renewed every three to four months: it became heavily impregnated with urine. When removed, one-half was crushed to a fine state by bullock power in a mortar mill, the other half was given over as manure to the fields (in very wet weather all was saved for use in the shed). This urine-earth, together with the wood ashes or ashes from the burning of the cow-dung as fuel, was an essential ingredient of the compost.
Every day one and a half stretcherfuls (pals) of the stacked vegetable material were thrown under each pair of bullocks in the shed, together with one-twentieth of this amount of hard or resistant material which had been steeped or damped; uneaten food or damaged silage was used to cover any wet floor patches. The cattle slept on this bedding, which was thus further crushed and broken and impregnated. The next day, a little of the fresh dung was removed to make into slurry, and the remainder (when not otherwise required) carefully distributed; two-fifths of a bowl(tagari) of urine-earth was then scattered; the whole mass, being the wastes of two animals, was then spaded (we should consider it rather as raked) to one end and removed by stretcher to the composting site; the process was repeated throughout the shed. When cleared, all wet patches of the floor were scraped out and fresh earth strewn before the next day's distribution of bedding; in this way the shed was kept sweet and free of flies. During the rains, care was taken to make the bedding up in three layers, a bottom and top layer of dry material specially reserved for this purpose, with the remainder of the material in between.
The wastes, thus carefully prepared and manipulated beforehand, were found to be very homogeneous. They were brought on the pals to the compost pits, beside each of which were waiting small heaps of fresh dung, of ashes, of urine-earth, and of old inoculated material taken from a pit ten to fifteen days old, also a tub of thin slurry, i.e. of liquid obtained by adding water to small amounts of all four materials mixed together. All quantities were measured with accuracy but quite easily by means of the tagari (the quantities are given and also converted into lb. in Table IV and on p. 69 of The Waste Products of Agriculture) and the layers of bedding or dung were two inches thick, then sprinkled with urine-earth and finally wetted with the slurry. Another watering in the evening and a third slight watering the next morning completed the charge. Subsequent waterings, again of measured quantities, were given at stated intervals.
During the rains, when the pits were liable to be flooded, composting had to be transferred to heaps, but decomposition did not take place so evenly. There followed processes of turning once, twice or even a third time, at intervals respectively of sixteen days, one month, and two months after charge; these turnings were accompanied by fresh waterings, always in measured quantities; eventually six waterings were given.
It is almost surprising, in view of the elaborate nature of these operations, that the Indore Process caught on in other parts of the world very shortly after publication of the book. A careful reading of the text will, however, make plain that the turnings thus undertaken were not complete turnings as now commonly understood; one-half of a heap was doubled over the other undisturbed half; thus, in fact, only one-half of the material was turned on each occasion. Only at the third turn was the material wholly removed from the pit and placed alongside, the contents of several pits being put together to save space. This corresponds with what is usually now done when compost is removed from a heap for ripening.
The extraordinarily careful nature of the operations thus worked out in great detail after innumerable tests needs no emphasis. Nothing was lost by this. It was well to start thus elaborately, perhaps we might even say laboriously. Time was soon to bring confidence. It was found that two turns, if the whole material were moved, were amply sufficient; then only one was used, and this now remains a common practice. Sir Albert himself at the time of his death was experimenting in his small garden at Blackheath in allowing the compost to remain in a New Zealand compost bin until made, relying only on the final turning out for ripening. He had come to the conclusion that provided the wastes were varied, divided, and intimately mixed rather than layered, good compost could result without turning, and many compost makers proceed on this basis with success. (In spite of the elaborate nature of the process at Indore no extra labour beyond the two men and three women ordinarily employed on cattle-shed work was required, except at the third turn, when three men and four women were required at each pit for six hours. The regular staff of five spent half their time on the care of the cattle and half on making compost, the cost working out at 8.5 annas or 9-1/2d. per cart-load of made compost. This was established by exact records kept in 1930, when 840 cart loads were made. Sir Albert attributes the low cost of making to careful planning and arrangement and also to careful training of labour so as to work quickly and without unnecessary fatigue.)
The process as thus worked out with attention to the smallest details was the result of much experimentation into various possibilities. For four years trials were made with different single materials, cotton-stalks, pigeon-pea stalks, cane trash, weeds (green and withered), sann hemp (green and withered). In some cases ADCO was employed as the source of nitrogen, in others cattle-dung and urine-earth. The results from single materials were never entirely satisfactory. The cotton-stalks broke down rapidly at first, due to the presence of the green leaves, but then slowed down, and it took 150 days instead of the usual ninety to obtain a usable product; when composted with ADCO, temperature of the heaps was always irregular, the product was coarse and included partially decomposed substance. Results with pigeon-pea stalks and cane trash were still more unsatisfactory; even when passed through the cattle shed these materials were only half-decomposed at the end of six months. Weeds and sann hemp, on the other hand, tended to pack; they started with too high a nitrogen content and serious losses took place. Pits which started respectively with 44.2, 42.8, 49.7 lb. of N ended with only 25.7, 28.4, 29.2 lb., proving losses at the rate of 41.8, 33. 8, 41.3 per cent, whereas a control heap of mixed residues, starting with 28.3 lb., gained 1.3 lb. or at the rate of plus 4.4 per cent. (Table VIII, p. 84, of The Waste Products of Agriculture.)
It was these experiences which pointed to the rule enforcing the mixing of wastes, in imitation of what is so invariable in Nature. An interesting table gives the exact chemical content of twenty-two raw materials used in making Indore compost.
Composition of the Raw Materials Material Organic matter Ash Proteins Fats Fibre Soluble carbo-hydrates Nitrogen Malvi cotton-stalks (with leaves and pericarps) 90.17 9.83 7.35 3.2 36.09 43.53 1.176 Cambodia cotton-stalks 96.91 3.09 4.00 1.11 45.31 46.49 0.64 Cambodia cotton leaves 87.45 12.55 14.06 8.49 8.71 56.19 2.25 Cambodia cotton pericarps 95.26 4.74 11.44 9.81 45.21 29.07 1.83 Mixed weeds 69.48 30.52 10.87 2.05 21.92 34.64 1.74 Sann hemp, 12 weeks old, stems 96.30 3.70 4.00 1.06 53.61 37.64 0.64 Sann hemp, 12 weeks old, leaves 90.64 9.36 14.26 2.90 20.70 52.80 2.29 Sesbania indica, 6 weeks old 89.33 10.67 14.90 3.45 22.33 48.67 2.38 Pigeon-pea stalks 91.08 8.92 4.37 1.90 39.64 45.17 0.70 Sugar-cane trash 94.09 5.91 2.00 1.25 42.16 48.73 0.32 Water hyacinth 75.80 24.20 9.37 - - - 2.17 Leaves: (Ficus religiosa) 81.37 18.63 3.00 1.33 26.89 58.18 0.48 (Ficus indica) 82.08 17.92 2.18 1.12 28.37 50.39 0.35 Mixed dried grass 83.80 16.20 4.25 1.55 26.20 40.20 0.68 Millet stalks 89.90 10.10 2.24 - 25.42 51.57 0.70 Millet silage 89.20 10.80 4.53 1.55 26.87 51.10 0.79 Rice straw 8.90 19.10 2.25 1.05 35.10 40.40 0.36 Wheat straw 84.70 15.30 3.01 0.98 35.69 37.93 0.58 Pigeon-pea residues 86.80 13.20 11.01 4.40 19.23 44.67 1.99 Gram residues 85.70 14.30 4.68 2.27 26.71 45.86 0.75 Ground-nut residues 86.60 13.40 12.06 2.20 16.60 39.24 1.93 Ground-nut husks 85.80 14.20 7.57 2.80 55.35 13.73 1.21
The chemical composition of the materials, especially the nitrogen content, obviously varied greatly. To begin with a general carbon-nitrogen ratio of about 33:1 and to keep this uniform throughout the year the different materials had therefore to be combined. On completion of the process the carbon-nitrogen ratio is found to be adjusted to the normal 10:1 ratio characteristic of humus.
Losses of nitrogen also occurred when pits were made too deep, 4 ft. instead of 2 ft. Two feet was found to be the maximum distance to which air could penetrate in sufficient volume. Again the figures are interesting. Pits holding just over 4,500 lb. of material, with nitrogen content of 31.25 lb. in the 4-ft. pit and 29.12 lb. in the 2-ft. pit, showed at the end of the process that the 4-ft. pit had lost 1.76 lb., a percentage loss of 6.1, while the 2-ft. pit had gained 3.24lb., a percentage gain as high as 11.1.
Temperature records showed a high temperature established at the outset, namely about 65 deg. C (149 deg. F. ) and a regular rise of temperature after each turn. The temperatures in different parts of the pits showed themselves as extraordinarily uniform (figures in Table XVII, p. 97, of The Waste Products of Agriculture), proving that fermentation was very even; examinations were made five times in the cold weather, twice in the hot weather, four times in the monsoon, diagonally, vertically, removing a 6-inch layer and at random, for the top, middle and bottom of the pits: temperatures thus ascertained for the different portions of the compost mass varied at most by 2 deg. C., sometimes by 1deg. or half a degree, and on several readings not at all. Thus the internal temperature resulting from fermentation was clearly very stable, but was liable to be affected by wind, which could on occasion lower readings, when in the monsoon heaps had to be used instead of pits, by as much as anything between one and 12 deg. C. as between the leeward and windward side of the mass. This led Sir Albert later to stress the importance of seeking a sheltered site for compost-making. Sudden temporary drops in air temperature, however, had no effect; the intense fermentation could not be checked by a cold spell, but wind was a different matter.
In recent years much attention has been paid to the nitrogen balance sheet of composting; the absurd statement has even been made that nitrogen is lost in the process. The exact contrary is proved by the Indore work; nitrogen was gained by fixation from the atmosphere, in standard heaps, made with one-quarter of the available dung, in amounts from just over 4 to just over 11 per cent. Other heaps showed wider variations.
Nitrogen Balance Sheet in Normal Pits and Heaps No. Description Total nitrogen (lb.) at the beginning Total nitrogen (lb.) in the finished product Total gain of nitrogen (lb.) Percentage gain of nitrogen Pit 14 Standard (quarter dung) 29.12 32.36 3.24 11.1 Pit 15 Full dung 32.70 34.87 2.17 6.6 Pit 16 Dry dung 30.41 32.33 1.92 6.3 Pit 18 Full dung (residues low in nitrogen) 29.10 36.77 7.67 26.3 Pit 19 Dry dung 29.55 30.70 1.15 3.9 Pit 20 Standard (quarter dung) 24.73 25.80 1.07 4.3 Pit 21 Full dung (half period in monsoon) 33.25 33.40 0.15 0.45 Heap 22 Monsoon 22.28 29.52 1.24 4.4
The results showed that much depended on the make-up of the original material. If the nitrogen content of the wastes was too high at the beginning, nitrogen was always lost between charging and the first turn; nitrogen was also lost if the final product was kept too long in storage (figures for these losses, Tables XXII and XXIII, p. 102, The Waste Products of Agriculture); it needed to be used on the crop or banked by application to the land, when it became so diluted with such large volumes of dry earth that all further change was checked. This intricate question of nitrogen gain and loss was far from being exhaustively analysed at Indore. It is a very great question and has given rise to an immense amount of investigation, not of course in any way limited to what happens in composting. But even in this limited field Sir Albert notes that further enquiry as to what happens in the heaps will be interesting with a view to determining the exact conditions under which a large amount of nitrogen could be gained from the atmosphere by careful manipulation. In the final product the carbon-nitrogen ratio was found to be not far from the ideal figure of 10:1, which meant that the nitrogen was in a stable form, such as not to permit liberation (i.e. loss) beyond the absorption capacity of the crop. The exact chemical analyses of twelve pits or heaps are recorded.
Composition of the Final Product No.of Pit or Heap Materials used Organic Matter Total Ash Silicates and Sand Nitrogen P2O5 K2O C/N Soluble Humus Fineness Heap Cotton-stalks with reduced (quarter) dung 33.915 66.085 34.97 1.61 0.48 3.38 16.5:1 11.56 68.15 Pit 7 Dry mixed residues 20.135 79.865 46.91 0.90 0.41 1.95 11.2:1 5.56 72.3 Pit 14 Dry mixed residues 19.66 80.34 46.32 0.84 0.68 2.35 11.6:1 6.27 88.5 Pit 8 Dry mixed with full dung 20.185 79.815 46.27 1.004 0.51 3.05 10.8:1 4.83 81.3 Pit 15 Dry mixed with full dung 18.385 81.615 51.33 0.725 -- 2.43 12.6:1 3.86 82.5 Pit 5 Dry mixed with full dung 19.76 80.24 50.11 0.841 0.403 2.23 11.7:1 5.29 84.0 Results obtained in the monsoon Heap 6 Mixed withered weeds 21.25 78.75 47.55 0.862 09.43 2.33 12.3:1 4.01 76.3 Heap 10 Mixed withered weeds 22.055 77.945 47.77 0.808 0.49 4.99 13.6:1 4.07 78.4 Heap 22 Mixed withered weeds 22.09 77.91 48.45 0.914 0.51 3.59 12.0:1 4.31 75.7 Heap 34 Mixed withered weeds 19.375 80.625 48.70 0.625 0.59 5.31 15.5:1 4.27 79.4 Heap 40 Half-withered weeds, half sann 21.05 79.95 47.61 0.825 0.55 2.85 12.75:1 5.96 78.6 Heap 42 Dry mixed residues 21.685 78.315 46.41 0.806 0.62 3.65 13.5:1 5.36 84.0
Some figures are finally given for the results of compost on the permeability of soils. These effects on the physical condition of soils are now admitted and have been established by innumerable observers. It is generally conceded even by the most hard-bitten opponents of the Organic School that composting has excellent physical influence on soils.
The Results and Significance of the Process
It was one of Sir Albert's hopes that composting would have a direct bearing on general social welfare in India by providing a system for the proper disposal of night soil and thus finally putting an end to the dismal toll of disease and death in the Indian villages arising from the improper disposition of these human wastes anywhere and everywhere. He was much influenced by the pioneer efforts of Colonel F. L. Brayne, I.C.S. , Deputy Commissioner in the Gurgaon district of the Punjab and later of Jhelum, whose work in teaching the Indian peasantry to construct latrines and clean up their villages generally was greatly admired by Sir Albert. It was his belief that composting would carry this ideal a stage further and that 'cleaner and healthier villages will go hand in hand with heavier crops'. (Final words of the Preface to The Waste Products Of Agriculture.) Had he lived to see the work now being carried out among peasant communities in such widely separated countries as Nigeria, the territories of East Africa, the Seychelles Islands, etc., he might have declared himself no mean prophet: nothing is of happier augury than to read of the astounding spread of the combined principle of improved sanitation and improved agriculture among communities which so sadly need both, on methods which in all essential respects follow the Indore system, whether or no one wishes to attribute the origin of such methods directly to the work at Indore: let it be enough that the idea has spread, not only among peasant communities but throughout the civilized world. It was the merit of the experiments at Indore that they reintroduced to the world of science, in a way both exact and comprehensive, the Chinese master conception of the restoration of all wastes to the soil by continuous processes of decay. In pointing to the great gap in Western thought which so curiously ignored the significance of these wastes, in drawing for remedy both on contemporary scientific discovery and on age-old Eastern practice, above all, in insisting that the use of these wastes must be systematic and controlled, Sir Albert Howard rendered an immense service at a time when it was peculiarly needed: the Indore Process would not have had its world-wide success -- and it may be added its flood of imitations -- had it not been most urgently required. It is a fact which has now become clear that the soils of the world are liable to run down when cultivated; this deterioration has lately accelerated in an alarming degree.
The Floor of the Forest
Throughout Sir Albert Howard's work one thing stands out, and that is his extraordinary genius for observing and interpreting natural phenomena: there was an inextricable mixture in his mind of what Nature could do and what man could do. His first definition of agriculture was to call it 'an interference with Nature'. He may be said to have spent his life in determining the exact limits to which man could carry that 'interference'.
Those limits can only be determined by measuring them against a standard, which is the end result of the constant interaction of gases, solids and liquids, minerals, organic substances, plants and animals, imposed by Nature on this world of ours after 'experiments' lasting aeons: this final formulation is very old, very delicately adjusted, yet eventually unshakable. It is often called 'the balance of Nature', an expressive phrase capable of some misuse. It was late in life that Sir Albert picked out the floor of the forest as the most perfect illustration of a natural standard of soil fertility.
This phrase does not occur in The Waste Products of Agriculture, but I well remember a day, a few years after that book had appeared, when we visited the lovely Lerins Islands off Cannes, where forest had been left untouched for a prolonged period; I did not at that time appreciate the reasons for the excitement which overtook my husband and his friend, the late George Clarke, in finding huge earthworm casts in immense abundance. It is likely that the impression received on that occasion was an insistent one and that it was on that day above all others that came the clear conception not only of the part played by the earthworm in the making of humus, but also of the peculiarly rich and abundant life which the forest shows even on the animal side, a fact so often overlooked in countries where civilization has destroyed the larger wild fauna; this disappearance is compensated by an abundance of smaller and especially of insect life. The lesson of the forest also brought home the important point that ligneous material should be included in the use of wastes, corresponding with the fallen twig, branch or even tree trunk. That diseased material was never eliminated by Nature, but always subjected to the ordinary processes of decay and re-used, was greatly stressed in later years. Finally, this reserve of valuable material is most beautifully protected by the forest canopy and magnificently anchored in place by the forest roots. Thus every detail which had to be taken over by man is to be found in this natural example.
Given this and similar examples, there is almost no limit to what man can do. It is a great mistake to picture Sir Albert Howard's outlook as slavishly subordinate to a kind of Nature worship. He was a very bold and courageous innovator, optimistic and adventurous, and surely a most successful cultivator of the earth's surface. He scorned the idea that men could not feed themselves, or grow what they wanted when they wanted it and as they wanted it. They would have to know what they were about, and to deal with Nature on the terms she imposed: to go against ultimate truths was death. But even a limited amount of manipulation might bring enormous gain.
Thus the transference from one Eastern country to another of a highly beneficial practice and its establishment on a firm scientific basis had already solved the very ancient and disastrous problem of the manuring of the fields of India. It was too soon to foresee the world consequences which so quickly followed on the Indian experience, yet even at that date this optimistic mind could declare that 'the practical results obtained at Indore prove that all that is needed to raise crop production to a much higher level throughout the world is the orderly utilization of the waste products of agriculture itself.' (The Waste Products of Agriculture, p. 57.)
The Waste Products of Agriculture: their Utilization as Humus, 1931.
The Application of Science to Crop Production, 1929, pp. 38-42.
Agric. Journ. of India, Vol. XX, Part V, Sept. 1925: 'The Water Hyacinth and its Utilization'.
Journal of the Roy. Soc. of Arts, Vol. LXXXII, No. 4229, 8th Dec. 1933: 'The Waste Products of Agriculture: their Utilization as Humus'.
Ibid., Vol. LXXXIV, No. 4331, 22nd Nov. 1935: 'The Manufacture of Humus by the Indore Process'.
Next: 7. Relations with Cultivators and the Treatment of Labour
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