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(The Soil and Health)
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Chapter 6
The Intrusion of ScienceIt was Francis Bacon who first observed that any species of plants impoverished the soil of the particular elements which they needed, but not necessarily of those required by other species. This true observation might have put subsequent investigators on the right path had their general knowledge of scientific law been less fragmentary. As it was, many ingenious guesses were made in the course of the seventeenth and eighteenth centuries as to the nurture and growth of plants, some near the truth, some wide of the mark. Confusedly it began to be recognized that plants draw their food from several sources and that water, earth, air, and sunlight all contribute. Priestley's discovery of oxygen towards the end of the eighteenth century opened up a new vista and the principles of plant assimilation soon came to be firmly established, by which is meant the fact that under the influence of light the green leaves absorb carbon-dioxide, break it up, retaining the carbon and emitting the oxygen (hence their purifying effect on the atmosphere) -- what is more delicious than the air of the forest, garden, or field? -- while without light, i.e. during the night-time, plants reverse the process and emit carbon-dioxide. Though the investigation of the parallel processes of root respiration, i.e. the use made by the roots of the oxygen available from the soil-air or the soil- solution, did not follow until a good deal later, yet the foundations of knowledge about the life of plants were at least thus laid on sound lines.
The Origin of Artificial Manures
It was at this juncture that a special direction was given to investigation by Liebig. Liebig is counted the pioneer of agricultural chemistry. His Chemistry in Its Application to Agriculture, contributed to the British Association in 1840, was the starting point of this new science. His inquiries into general organic chemistry were so vast and so illuminating that scientists and farmers alike naturally yielded to the influence of his teaching. His views throughout his life remained those of a chemist and he vigorously combated the so-called humus theory, which attributed the nourishment of plants to the presence of humus. At that time the soil in general and the humus in it were looked on as mere collections of material without organic growth of their own; there was no conception of their living nature and no knowledge whatever of fungous or bacterial rganisms, of which humus is the habitat. Liebig had no difficulty in disproving the role of humus when presented in this faulty way as dead matter almost insoluble in water. He substituted for it a correct appreciation of the chemical and mineral contents of the soil and of the part these constituents play in plant nourishment.
This was a great advance, but it was not noticed at the time that only a fraction of the facts had been dealt with. To a certain extent this narrowness was corrected when Darwin in 1882 published The Formation of Vegetable Mould Through the Action of Worms with Observations of Their Habits, a book founded on prolonged and acute observation of natural life. The effect of this study was to draw attention to the extraordinary cumulative result of a physical turnover of soil particles by natural agents, particularly earthworms. It was a salutary return to the observation of the life of the soil and has the supreme merit of grasping the gearing together of the soil itself and of the creatures who inhabit it. Darwin's book, based as it is on a sort of experimental nature study, established once for all this principle of interlocked life and, from this point of view, remains a landmark in the investigation of the soil.
Meanwhile Pasteur had started the world along the path of appreciating the marvellous existence of the microbial populations traceable throughout the life of the universe, unseen by our eyes but discoverable to the microscope. The effect of his investigations has been immense; enormous new fields of science have been opened up. The application of this knowledge to agriculture was only gradual. Many years slipped by before it was realized that the plants and animals, whose life histories are based ultimately on living protoplasm, have their counterparts in vast families and groups of miscroscopic flora and fauna in the very earth on which we tread.
It thus came about that the chemical aspects of the soil for a long time predominated in the mind of the scientist. The theory had had a good start, it was older and naturally better developed. Moreover, and this is important, Liebig had been a pioneer not only in science, but in practice. From the outset of his experiments he had made every effort to work with the farmer and also by field investigation. The farmer did not object to the help given him in his difficult task. As the demands on him grew to fever pitch, for he was just facing the heavy, cumulative greed of the expanding factories of the world and the hunger of their servants, the workers, he not unnaturally welcomed ideas and suggestions which he was told would enable him to carry out his task in an easy, practical, and clean way without fuss and without that extra labour already so difficult to procure.
Thus artificial fertilizers were born out of the abuse of Liebig's discoveries of the chemical properties of the soil and out of the imperative demands made on the farmer by the invention of machinery. It must be confessed that Liebig himself was somewhat of a sinner on this count. He manufactured artificial manures and though these were oddly enough a failure he maintained his faith, which indeed was questioned by none, that the food of plants could be replenished by the too obvious principle of putting back into the earth the minerals which, as the analysis of the ash of the burnt crops taken off it revealed, were drawn out by the plants.
As long as this principle was held to override every other consideration, no further progress could be made. The effects of the physical properties of the soil were by-passed: its physiological life ignored, even denied, the latter a most fatal error. There was a kind of superb arrogance in the idea that we had only to put the ashes of a few plants in a test tube, analyse them, and scatter back into the soil equivalent quantities of dead minerals. It is true that plants are the supreme, the only, agents capable of converting the inorganic materials of Nature into the organic; that is their great function, their justification, if we like to use that word. But it was expecting altogether too much of the vegetable kingdom that it should work only in this crude, brutal way; as we shall see, the apparent submission of Nature has turned out to be only a great refusal to have so childish a manipulation imposed upon her.
At first all seemed to go well. As economic conditions pressed on the farmer more and more severely, he thankfully grasped at the means of increasing the volume of his production and after the great agricultural depression of 1879 began to use the artificial manures placed on the market for his benefit. These were of two kinds; the nitrogen artificials which supply the current account of plants and which have a marked effect in increasing leafage, and the potash and phosphate artificials which increase the mineral reserves of the soil. The chemical symbol for nitrogen is N; for potassium, K (for Kalium); and for phosphorus, P; and the attitude of mind which sees all virtue in the use of artificials may fairly be dubbed the NPK mentality.The Advent of the Laboratory Hermit
Stimulating the growers who began to acquire this mentality, there came to be installed in the strongholds of science a type of investigator whom we are justified in naming the laboratory hermit. The divorce between theory and practice was a new phase which would have been deprecated by Liebig, but the temptation to grow a few isolated plants in pots filled with sand -- watered by a solution containing the requisite amount of NPK in a balanced form so that any one constituent did not outdo the others -- draw them, measure them, tie them up in muslins, weigh them, burn them, and analyse them proved too great. A quantity of minute investigation was based on these practices, which are only justified as a mere introduction to agricultural investigation. Though the plant may to some extent be grown under these conditions, the soil is another problem. Soil or watered sand in a flower-pot is literally in a straitjacket and it is nonsense to assume that it can carry on its proper life: for one thing the invasion of earthworms or other live creatures is eliminated and many other processes put out of action. That essential co- partnership between the soil and the life of the creatures which inhabit it, to which Darwin's genius had early drawn attention, is wholly forgotten.
To confirm the findings of the flower-pots the small plot trials -- in which some fraction of an acre of land is the usual unit -- were devised. Great virtues have been attributed to the repetition of such tests over a long period of years and, of late, to the statistical examination of the yields. In this way it was hoped to "disentangle the effects of various factors and to state a number of probable relationships which can then be investigated in the laboratory by the ordinary single factor method". (Russell, Sir John, Soil Conditions and Plant Growth, London, 1937, p. 31.)The Unsoundness of Rothamsted
At this point the manifold weaknesses of the small-plot method of agricultural investigations must be emphasized. The celebrated Broadbalk wheat trials at Rothamsted, the units of which are strips of land some half an acre in size and on whose results the artificial manure industry is largely founded, can be taken as an example. The trials have been repeated for some hundred years, the work has been carried out with extreme care, the fullest records have been kept and preserved, and the final figures have been subjected to the best available statistical analysis.
The main object of these experiments was to determine whether wheat could be grown continuously by means of artificials alone or with no manure, and also to compare the results obtained by chemicals on the one hand and by farmyard manure on the other. The results are considered to prove that under Rothamsted conditions satisfactory yields of wheat can be obtained by means of chemicals only, that no outstanding advantage follows the use of farmyard manure, and further that on the no-manure plot a small but constant yield of grain can be reaped. A subsidiary, but very important, result is also claimed, namely, that the manuring has had no appreciable effect on the quality of the wheat grain.
In spite of all the devotion that has been lavished on these Broadbalk trials, at least four major mistakes have been made in their design and conduct which completely discredit the final results.
In the first place, an error in sampling was made at the very beginning. A small plot cannot possibly represent the subject investigated, namely, the growing of wheat, which obviously can best be studied in this country on a mixed farm. We cannot farm a small strip of wheat land year after year, because it is difficult to cultivate it properly; the area does not come into the usual rotations and is, therefore, not influenced by such things as the temporary ley, by the droppings of livestock, and by periodic dressings of muck. The small plot, therefore, cannot represent any known system of British farming, any of our farms, or even the field in which it occurs. It only represents itself -- a small pocket handkerchief of land in charge of a jailor intent on keeping it under strict lock and key for a century; in other words, it has fallen into the clutches of a Gestapo agent. In this sinister sense the Broadbalk trials have indeed been permanent.
In the second place, the continuous cultivation of wheat on a tiny strip of land is certain to create practical difficulties. Such land cannot be kept free from weeds because of the short time available between harvest in August and re-sowing in October. No cleaning crops like roots crop can, therefore, be used. This difficulty duly happened at Rothamsted. The weeds got worse and worse and finally won the battle. Mother Earth rejected the idea underlying the continuous wheat experiment. The original conception of these trials has had to be modified. Fallows have had to be introduced. I last saw these Broadbalk plots about 1918 when this weed difficulty was causing considerable concern. I can truthfully say that never in my long experience have I seen arable land in such a hopeless and filthy condition. A more glaring example of bad farming could scarcely be imagined. I took my leave at the earliest possible moment and decided then and there that my last visit to Rothamsted -- the Mecca of the orthodox -- had been paid.
In the third place, no steps were taken to isolate the plots from the surrounding areas and to prevent incursions from burrowing animals such as earthworms. It is known from the work of Dreidax (Archiv far Pflanzenbau, 7, 1931, p. 461) and others on the Continent that when the earthworm population is destroyed by artificials, the affected areas are soon invaded by a fresh crop of worms from the neighbouring land. This invasion may take place at the rate of many yards a year. To study the effects of artificials on earthworms Dreidax showed that the experimental area should be at least ten acres and that the fringes of this land should never be taken into account. We know that artificials, sulphate of ammonia in particular, destroy the earthworm population wholesale (the use of sulphate of ammonia for destroying earthworms on golf putting greens is recommended in Farmers' Bulletin 1569 issued by the United States Department of Agriculture), but that after the nitrification of this manure has taken place the area is again invaded by more of these animals. A small oblong strip about half an acre in size is, therefore, obviously useless for determining the effect of artificials on the soil population. The unit should be a square at least ten acres in area. This wholesale destruction of the earthworm probably helps to explain the failures in wheat growing which often attend the application of the Rothamsted methods to large areas of land. The lowly earthworm -- the great conditioner of the food materials for healthy crops -- is murdered and no effective substitute is provided.
In the fourth place, the manurial scheme has never been allowed to impress itself on the variety of wheat grown. The manuring has influenced the soil, but not the plant. The seed used every year has been obtained from the best outside source. The wheat raised on each plot has not been used to sow that plot for the next crop. The plant has had a fresh start every sowing. The Broadbalk experiment is, therefore, not a continuous wheat experiment as regards one of the two most important factors in the trial -- the wheat plant itself. How this error crept in is difficult to say. It was most probably due to over-emphasis on the soil factor. Its discovery is largely due to Mr. H. R. Broadbent, who has made a critical study of the published reports on the Broadbalk plots from the beginning with a view to discovering the cause of the discrepancy between the Rothamsted experience and the results of large-scale wheat growing when carried out on the farm. In the discussions which arose Mr. Broadbent asked me where the seed sown every year on these plots came from. As this important fact was not recorded in the various Rothamsted Annual Reports, I asked the authorities to let me know the source of the seed used in the Broadbalk trials and was promptly informed that fresh seed was obtained every year from the best outside source and that the crop from each plot was never used to re-sow that plot. This candid confession invalidates the entire Broadbalk experiment. Had the harvest of each plot been used for resowing, in a very few years an important result would have been obtained. The effect of artificial manures, which we know is cumulative, would soon have begun to influence the stability of the variety itself and cause it to run out. In some period between twenty-five and fifty years the wheat would have ceased to grow and the Broadbalk experiment would have collapsed. This dramatic result, in all probability, would have saved the agriculture of this country and of the world from one of its greatest calamities -- the introduction of artificial manures into general practice.Artificials During the Two World Wars
In 1914, when the first world war broke out, the Broadbalk results were universally accepted as a safe guide for the farmer in the drive for increased food production. But it was the after-effects of this war rather than the four years of the war itself which ushered in a yet more ardent use of artificial fertilizers. The new process of fixing, i.e. combining, nitrogen from the air had been invented and had been extensively employed in the manufacture of explosives. When peace came, some use had to be found for the huge plants set up and it was obvious to turn them over to the manufacture of sulphate of ammonia for the land. This manure soon began to flood the market.
From 1918 onwards the application of artificials was earnestly advocated by all authorities; their use was laid on the farmer almost as a moral duty. The universities had by now been impelled to set up agricultural departments, and finely equipped experiment stations were scattered over the various countries which in their general theory of investigation copied the universities, from which, indeed, they were invariably recruited. All these agencies without exception gave unconscious stress to the NPK mentality and were also hypnotized by the thraldom of fear of the parasite. Two thoroughly unsound and even mischievous principles thus acquired the support of the republics of learning -- the universities -- and the sanction of science itself. When the present war broke out the stage was set for the next swift advance towards the steep places leading downwards to the sea.
When towards the end of 1939 the menace of the submarine began to imperil our food supplies from overseas, it became crystal clear that the fields of Great Britain would have to grow more and more of our nourishment if starvation were to be avoided. Then for the first and perhaps for the last time artificial manures came into their own: they were available in quantity to stimulate the crops: the Defence Regulations could be invoked to support the grow-more-food policy: the financial resources of a great nation were available to help the farmers to purchase these chemical stimulants and thus indirectly to subsidize the artificial manure industry itself: the staffs of these vested interests were at the disposal of the Ministry of Agriculture: the local War Agricultural Executive Committees soon became salesmen of the contents of the manure bag: the frequent speeches of the Minister of Agriculture invariably contained some exhortation to use more fertilizers. The amalgamation of the vested interests and the official machine which directed war farming became complete. One thing, however, was forgotten. No satisfactory answer to the following question has been provided: What will be the final result of all this on the land itself, on the well-being of crops, livestock, and mankind? Will the grow-more-food policy have solved one problem -- the prevention of starvation -- by the creation of another -- the enthronement of the Old Man of the Sea on farming itself? What sort of account will Mother Earth render for using up the last reserve of soil fertility and for neglecting her great law of return? Who is going to foot the bill?The Shortcomings of Present-day Agricultural Research
But the enthronement of the NPK mentality is only one of the blunders for which the experiment stations must be held responsible. The usual sub-division of science into chemical, physical, botanical, and other departments, necessary for the sake of clarity and convenience in teaching, soon began to dominate the outlook and work of these institutions. The problems of agriculture -- a vast biological complex -- began to be subdivided much in the same way as the teaching of science. Here it was not justified, for the subject dealt with could never be divided, it being beyond the capacity of the plant or animal to sustain its life processes in separate phases: it eats, drinks, breathes, sleeps, digests, moves, sickens, suffers or recovers, and reacts to all its surroundings, friends, and enemies in the course of twenty-four hours, nor can any of its operations be carried on apart from all the others: in fact, agriculture deals with organized entities, and agricultural research is bound to recognize this truth as the starting point of its investigations.
In not doing this, but adopting the artificial divisions of science as at present established, conventional research on a subject like agriculture was bound to involve itself and magnificently has it got itself bogged. An immense amount of work is being done, each tiny portion in a separate compartment; a whole army of investigators has been recruited, a regular profession has been invented. The absurdity of team work has been devised as a remedy for the fragmentation which need never have occurred. This is nonsensical. Agricultural investigation is so difficult that it will always demand a very special combination of qualities which from the nature of the case is rare. A real investigator for such a subject can never be created by the mere accumulation of the second rate.
Nevertheless, the administration claims that agricultural research is now organized, having substituted that dreary precept for the soul-shaking principle of that essential freedom needed by the seeker after truth. The natural universe, which is one, has been halved, quartered, fractionized, and woe betide the investigator who looks at any segment other than his own! Departmentalism is recognized in its worst and last form when councils and super-committees are established -- these are the latest excrescences -- whose purpose is to prevent so-called overlapping, strictly to hold each man to his allotted narrow path and above all to enable the bureaucrat to dodge his responsibilities. Real organization always involves real responsibility: the official organization of research tries to retain power and avoid responsibility by sheltering behind groups of experts. The result of all this is that a mass of periodicals and learned papers stream forth, of which only a very few contain some small, real contribution.
The final phase has been reached with the letting loose of the fiend of statistics to torment the unhappy investigator. In an evil moment were invented the replicated and randomized plots, by means of which the statisticians can be furnished with all the data needed for their esoteric and fastidious ministrations. The very phrase -- statistics and the statistician -- should have been a warning. It is, of course, true and known to most persons that average numbers and similar calculations are not perfect; they are subject to various errors. Care is needed in interpreting them and, above all, experience of the actual: where this is available and where common sense is the judge, danger ceases. The deduction would be, in what we are now reviewing, that the agricultural investigator must be well acquainted with practical farming and be prepared to put his conclusions to practical tests over some period of time before he can be certain of what he says. This conclusion is just, and with such a corrective agricultural experiment can live and prosper.
But the exactly opposite conclusion has been drawn. Instead of sending the experimenter into the fields and meadows to question the farmer and the land worker so as to understand how important quality is, and above all to take up a piece of land himself, the new authoritarian doctrine demands that he shut himself up in a study with a treatise on mathematics and correct his first results statistically. The matter has been pursued with zest and carried to all extremes; it is popularly rumoured that only one highly qualified individual is now able to interpret the mathematical principles on which are based the abstruse mass of calculations to which even the simplest experiments give rise.
But the proof of the pudding is in the eating thereof. Can the statistician give any practical help when the use of small plots gets into difficulties? In one case I personally investigated about 1936 the answer is: Most emphatically, no. This occurred at the Woburn Experiment Station, a branch of Rothamsted. During the summer I was invited by the Vice-President of the Rothamsted Trust, the late Professor H. E. Armstrong, F.R.S., to help him to discover why one of the sets of permanent manurial experiments at Woburn had come to an end. After a long treatment with artificials the soils on the greensand had gone on strike: the cereals refused to grow. Why? I have a vivid recollection of this visit. We were first given a learned lecture on the past history of the plots with tables and curves galore by the Officer-in-Charge. We then visited the field, for which the professor said I was certain to need a spade. We saw the plots which had given up the struggle. No crop was to be seen, only a copious growth of the common mare's tail (Equisetum arvense). I then inquired whether a really good crop could be seen on similar land. We were shown a fine crop of lucerne nearby which had been manured with copious dressings of pig muck. The cause of the going on strike of the Woburn plots was now clear and the cure was obvious, but before explaining all this to the Officer-in-Charge I inquired what had been done by the Rothamsted staff to elucidate this trouble. It appeared that all the data and all the information available had been laid before the Director and his staff, including the statisticians, but without result. Neither the official hierarchy nor the higher mathematics had any explanation or advice to offer. I thereupon explained the cause and pointed to the cure of the mischief. Constant applications of chemicals to this sandy soil had so stimulated the soil organisms that the humus, including the humic cement of the compound soil particles, had been used up. This had led to pan formation and to the cutting off of the air supply to the subsoil. All this was obvious by the establishment of a weed flora mostly made up of a species of Equisetum. My diagnosis would be confirmed by an examination of the soil profile which would disclose a sand pan some six to nine inches below the surface and the development of the characteristic root system of this weed of poorly aerated soils. This injurious soil condition could be removed by a good dressing of muck followed by a crop of lucerne. A soil profile was then exposed and there was the pan and the root system exactly as I foreshadowed. It was merely a case of reading one's practice in the plant. The establishment of the mare's tail on a high-lying sand could only be possible by poor soil aeration due, in all probability, to the formation of a subsoil pan so common in sandy soils. Farmyard manure, plus a deep-rooting crop and earthworms, would prevent pan formation, hence the good crop of lucerne. Long practical experience and many years spent in root studies had instantly suggested the cause of the Woburn trouble. Many years' observation and first-hand experience of the lucerne crop enabled me to suggest a cure for the pan formation. How could statistics and the higher mathematics be a substitute for the faculty of reading one's practice in the plant? How could this faculty be developed except by a wide experience of research methods and of practical farming?
Can statistics or the statistician help in unravelling the nature of quality -- that factor which matters most in crop production, in animal husbandry, and in human nutrition? We cannot measure or weigh quality and express the result in numbers which the statistician can use. But our livestock instantly appreciate quality and show by their preference, their better health, their improved condition and breeding performance how important it is. The animal, therefore, is a better judge of one of the factors that matters most in farming than the mathematician. But on this important point -- the verdict of the animal -- the records of our experiment stations are silent. At these institutions crops are weighed on metal or wooden balances so that figures -- the food of the statistician -- can be provided. But if many of these experimental crops, particularly those raised with chemical manures, are tested in the stomachs of our livestock -- the real balance of the farmer -- they will be found wanting.
The invasion of statistics into agricultural research has been an incursion into a diseased field. Let us sum up this chapter by judging this result of our modern civilization by its works. This surely is not unfair. Of some fifteen committees set up in Great Britain under the Agricultural Research Council just before the present war no less than twelve were allocated to investigation of the diseases of animals and plants. Of the enormous mass of scientific literature published on agricultural problems some third part is concerned with the onset, history, description, or attempted remedies for some form of sickness or disability in crops or livestock. This merely reflects the facts. Old diseases are spreading and new diseases are appearing. Eelworm devours our potato crop, foot-and-mouth disease infects our cattle, grass sickness kills our horses, fungi, viruses, and insect parasites invade our fruit and our vegetables: every vine in France is smothered in green and blue copper compounds to keep the mildews at bay. Comparatively new crops like the sugar beet are now retreating before the onset of the eelworm. New scientific organizations and their satellite companies for dealing with the increasing manufacture and sale of insecticides and fungicides are being created. The farmers are being urged to subscribe to panels of veterinarians to control the growing toll of disease among their livestock.
Even a Beveridge health plan is now being advocated by the National Veterinary Association, who also favour "the establishment of State breeding farms to facilitate the improvement of average stock by direct mating and by controlled artificial insemination" (Daily Express, 16th March 1944). The practice of artificial insemination for livestock can only be described as a monstrous innovation which can only end in life-erosion. Already many of the men who know most about animal breeding are in revolt; they are convinced this unnatural practice is bound to end in sterility and disaster.
The catalogue could be multiplied ad infinitum. The toll of disease is extraordinary and a matter of the utmost anxiety to the farmer. The public is not sufficiently aware of this unsatisfactory state of affairs. If these are the results of agricultural science, they are not encouraging and certainly are not impressive. They are undoubtedly a phenomenon of the last forty or fifty years and appear alongside of the modern use of artificial manures. This book asks the question whether we have here not things merely juxtaposed, but actual cause and result.
It is even more legitimate to ask what agricultural science would be at. It is a severe question, but one which imposes itself as a matter of public conscience, whether agricultural research in adopting the esoteric attitude in putting itself above the public and above the farmer whom it professes to serve, in taking refuge in the abstruse heaven of the higher mathematics, has not subconsciously been trying to cover up what must be regarded as a period of ineptitude and of the most colossal failure. Authority has abandoned the task of illuminating the laws of Nature, has forfeited the position of the friendly judge, scarcely now ventures even to adopt the tone of the earnest advocate: it has sunk to the inferior and petty work of photographing the corpse -- a truly menial and depressing task.
Next: 7. Some Diseases of the Soil
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