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   SOIL is the film of life which covers much of the land surface of this planet Earth. It is so thin that a light coat of paint on a large-scale model of the earth would be much too thick to represent to scale the thickness of the soil. But it is the home of all earthly life and the great raw material of agriculture. We will never know all there is to be known about soils, but if a farmer understands and has a feeling for soil life, he can manage his soil just as well as if he had all the accumulated knowledge of all the scientists who are concerned with soil and soil life.

   Soil is composed of rock fragments of every size and variety, representing all or nearly all the minerals of the earth's crust, together with an infinite variety of chemical and organic compounds made up of its rock particles, liquids and gases, all reacted on by the life that lives and dies in the soil and on the surface of the soil.

   Rock is broken down by all the agencies of climate, sunlight and heat, freezing and thawing, wind and rain, and by gases as in the oxidisation process, but the disintegrated material is not soil until it is invaded by life; until plant life grows in it and animal life lives on it, and until soil life develops and lives and dies in it and thus forms part of the earth itself. Once soil has started to form, the greatest influences on its ultimate development are always those factors that most influence these life forces of the soil. The higher the life forces within the soil, the greater is the fertility of the soil, and the maximum development that any form of life may attain depends on its living conditions and its food supply. This truth, therefore, is of vital importance in the management of soil.

   Monumental examples of this natural law can be seen in geology; for example, to mention only two cases, in the huge limestone deposits formed from the skeletons of a prehistoric life that developed rapidly in a favourable environment; and in the extensive coal deposits found in many parts of the world which represent an ancient vegetable life that flourished in a suitable climate and was nourished by a constant food supply.

   Soil has a climate of its own. It is composed of the three factors, moisture, warmth, and air in combination. Good soil climate produces the best in pastures and crops. The natural soil climate is dependent on the effect of general climate on the basic geological makeup of the soil. Climate is a dominating influence in agriculture as well as on soil quality.

   Soil is not, then, something that is dead. It is teeming with a great variety of life forms ranging in size from the submicroscopic viruses, through bacteria, microbes, fungi, to the colossus of the various species of earthworms. A mere handful of warm, moist, fertile soil contains a life population that is astronomical. Some of the species of soil life multiply at fantastic rates when conditions are suitable. Some species which increase by the mature individual dividing to form two, multiply so rapidly that if one single cell could conceivably have an inexhaustible food supply in good living conditions it would increase to a mass the size of the earth in a week or so. Many fascinating examples of the rapid rate of development of various species of soil life are contained in books on soil microbiology.

   Oddly enough, although many distinguished soil scientists have observed these phenomena and commented on them, none of them seem to have made the natural inference, namely, that soil development under optimum conditions can be very rapid indeed.

   Just about everything is food for some form of this soil life. Some live on others. Many are dependent on organic matter and some break down mineral elements for their food. The processes of living and dying form a variety of gases, acids and compounds. Minerals are acted on and altered to forms suitable for plant nutrition.

   Represented within the soil is probably every factor of health and disease of plant, animal and humans. This fact, somewhat clouded by magic, was appreciated instinctively by primitive man, and was incorporated in the pattern of tribal rites and cures. Civilised man for a long time forgot it, but this soil health factor has gained a new significance in recent years through the development of the antibiotics--all constituents of fertile soils. Nowadays many of the chemical processes of the soil are regulated and reproduced in the laboratories in medicine, chemistry and industry.

   A wide variety of some of the species of soil life seems to have a counterpart in the glands, organs and secretions of all animal life.

   While there are processes within the soil that may be detrimental to crops and animals and humans, there is always a heavy balance favouring the healthful nutrition of grasses, crops, animals and humans in all really fertile soils. These beneficial or benevolent factors operate at their best when the conditions of moisture, warmth and air are most suitable for the optimum production of the best pastures.

   Soil is dynamic and complete, forming and producing its own food supply. In a good soil the continuous production of vegetable matter, particularly the newly dead roots of pasture grasses, supply the force for its continuing processes.

   Good fertile natural soil was made or developed in a suitable climate by plants growing in the soil, by animals and birds feeding on the growth from the soil, and by the complex of soil life living in the soil and processing the necessary nutrients of plant growth. These same processes describe our agricultural pursuits. Therefore, soil controlled by the farmer and grazier should rapidly increase in fertility and not deteriorate as so much soil has been doing for so long.

   The development of soil is greatly influenced by climate. In the past, in my opinion, natural soil quickly reached its optimum development. It would then probably have maintained that particular fertility stage, only fluctuating slightly according to the varying climates from year to year. It would have reached a state of balance with all the factors that affect it, and remain relatively stable.

   This idea conflicts with the general impression that soil takes great ages to form. Some rocks, it is true, decompose very slowly, but the formation of the live soil from rock particles can be very rapid in a good environment.

   The study of soil life and all the soil-life processes is covered in soil biology, and particularly soil microbiology. There is probably a lot more to be learned about these various processes of the soil life than we yet know. But provided it is realised that to increase the quantities of vegetable matter in an environment that supplies the best conditions of moisture, warmth and air for soil life, is the outstanding way to accelerate the dynamics of this life, then the landman has the basic knowledge to greatly improve and increase the fertility of his soil. An improved soil climate itself acts to produce greater quantities of suitable organic matter and especially from the valuable root systems of pastures.

   Regionally, weather sets the course for the general agricultural pattern. Agriculture is dependent on soil, and soil is largely dependent on the climate that affects it.

   Perfect agricultural weather or climate, if it were possible anywhere, would soon produce perfect agricultural soil. Any soil, cleared of its unwanted growth of scrub and trees and planted to the best species of grasses and clovers would also rapidly increase in depth and fertility. If the effect of climate on soil is fully understood, I believe we have a basic knowledge that will enable us to increase the fertility and productivity of any natural soil. We have a knowledge that will allow us to increase the fertility of soil far beyond that which was produced in nature; but we need a new soil technology based on this knowledge.

   I am well aware of the influence of rocks and their mineral particles on the development of soil. Some rock types, for example the basalts which break down rapidly and release the essential mineral elements of fertility, will quickly produce a fertile or at least a productive soil in climatic conditions that would not produce a similar stage of fertility in another type of rock. There has always been a wide range in the fertility of natural soil produced under identical climatic conditions over a range of varying rock types. Some rocks have been reformed again after breakdown from original rocks and the disposition of, not only their mineral elements, but also the plant availability of these elements, have been widely changed. Some rocks will produce a complete soil with only one inch of decomposition from the hard rock; other rocks will need much deeper decomposition to supply all the mineral elements of fertility. Granites, apparently identical, may differ widely in fertility with only moderate variations in their general climatic influence.

   Soil on earths formed by wind deposits may produce maximum productiveness from minimum climatic influence. On the other hand, former good soil can deteriorate into poor soil by a changed climate that may cause the leaching down of a particular necessary element. Clearing and cultivating have first of all made way for good grass and good crops. Then, almost dramatically at times, the land seems to collapse and will not grow a crop or feed a sheep. The changed environment has caused a loss to the soil of a necessary mineral element resulting from a deterioration of the soil climate. Missing or unavailable mineral elements of fertility will never be very far away, but unless they are within the zone of plant roots they are not a part of the soil.

   A suitable climatic change could rapidly improve a soil and bring within range formerly missing elements of fertility.

   Disregarding for the moment the experiments being conducted by our Commonwealth Scientific and Industrial Research Organization (CSIRO) to produce rain, there is little we can do to improve climate. But as the critical factor is soil climate, are there ways and means of managing soil and land to improve the effect that the general climate has on soil climate?

   It is most conclusive that some types of soil treatment and land management do deteriorate the beneficial climatic effect on soil climate. The evidence is there in a deteriorated and eroding landscape. Before what is called soil erosion has its effect on soils that were originally of even moderate fertility, another very serious form of erosion took place. This is fertility erosion, which is a presoil erosion, and paved the way to major soil losses. It is caused by a change for the worse in the soil's climate, and the villain here is man.

   While there are numerous ways of worsening the soil climate to reduce the fertility of soil, and we have no doubt employed them all, there are, in my opinion, as many ways of improving the soil climate and increasing soil fertility.

   Good living conditions and plenty of soil-life food produce a soil that becomes increasingly more fertile. Perfect living conditions, or what amounts to the same thing, perfect soil climate, never exists and probably cannot exist continuously, but may be a present factor for short or longer periods once or more each year, according to the particular general climate. During the time that good soil climate extends to the limit of the food zone, the soil-life communities develop very rapidly to climaxes. The climax period in these conditions is limited only by the available food supply.

   As the various soil-life communities feed on each other, there has to be a continuous new source of food to balance the whole ecology and biology of soil. This continuous new source of food is some form of vegetable matter. All forms of vegetable life become part of soil by these processes, and, I believe, that the greatest source of best possible food supply is contained in the newly dead roots of the best clovers and grasses under a good pasture on which a variety of grazing animals have fed.

   Perfect soil conditions or soil climate involve a soil condition in which there is ample moisture but not complete saturation, a degree of warmth that suits most of the life forms, plus sufficient air for the life that needs it but not enough to dissipate overmuch warmth and moisture. These conditions produce the climaxes of soil life. To have maximum benefit they obviously must extend to at least the depth of the major root zone of a pasture.

   If these optimum conditions can be induced in the soil, even the recognised poorest of soil, once each year for three years, as in Keyline, then these poor soils, or any soil, can be improved to something beyond that which the natural climate produced. Further, once the greatly increased soil fertility has been produced and maintained for three years it has the ability within itself to improve its quality and depth without further treatment. Just how far or for how long this self-contained improvement will continue I have no way of knowing, but I am quite certain that the correct answer will reverse the present beliefs and that it takes much less time for man to build a bounteous fertility into his soil than it does for him to reduce, deteriorate and ruin that fertility.

   The practices and agricultural methods that deteriorate soil climate and reduce soil fertility may take many years to produce a noticeably harmful effect on good soil, but only a few seasons to destroy the low fertility of a poor soil.

   Altered practices that improve soil climate and fertility can create, because of the fantastically rapid response of soil life to better conditions and food supply, a highly fertile soil in a few short years; and it will always require a much longer time to destroy this fertility than it need take to build it.

   Perhaps the most dramatic evidence that there are many things wrong in our agriculture is the effect that it has produced on the land in ever-increasing soil erosion. I regard soil erosion as the perfectly natural reaction of land to change its shape in keeping with changing conditions of environment. But the stable shape of land, with its cover of soil, before it is brought into the category of agricultural land, represents a balance of all the conditions that affect it. If a soil that supports plant life and animal life has been produced naturally, then that soil is in balance with all the conditions that formed it and are continuing to act on it.

   The factors that have affected and produced natural land shape are very numerous, but those of its basic geology and climate are no doubt the dominating ones, since they produce or influence all the other factors that affect land shape and soil class.

   The features of land that make it suitable for agriculture are its soil coverage and its stable rounded or smooth form. These forms may range from large and low, as in our flatter land, to small and high, as in our steeply undulating hills and to all shapes between. Valley and hills are of a rounded smooth form.

   To produce the best agricultural shape and the deepest cover of soil requires a climate, not only agriculturally suitable but one that has been operating for a long period of time over stable geological conditions. The deeper rich soils formed and shaped under favourable climatic conditions are very stable. Fertile soil has within itself capacities that resist change, or, as it is called, soil erosion.

   When these natural soils and their land shapes are brought under agriculture many conditions may be altered and produce a lack of the former balance. The soil will eventually change and the land reshape itself to a new balance with the new conditions affecting it. (See Pictorial Section.)

   Fertile soil resists change or erosion, but changed conditions may reduce and destroy fertility, and then reshaping of the land form takes place. This is man-made soil erosion.

   For illustration, we can take the extremes of two classes of soil, both in a similar natural undulating landscape, one highly fertile soil, the other a very poor soil, and consider the changed conditions that affect them when they are converted to agriculture.

   Usually, the first thing to happen is that the land is surveyed and cut up into holdings or blocks with straight line boundaries which will be fenced. The fences cross hills, ridges, small and large valleys, watercourses and creeks with little regard to natural land divisions. Travelways, tracks and roads follow the fence lines and the first altered condition that may affect the land shape takes place. Water flowing over land has natural flowlines according to the land shape, and falls in curved lines to the valleys from the hills and ridges. It flows as a sheet, losing its natural flow path or pattern in the first depression. Roads and tracks cross these natural flow lines and cause water to concentrate earlier and in new places. The velocity of water moving on a hillside is greatly increased on a soil that did not develop in such conditions and is less able to support the flow without soil movement. When the velocity of water is doubled its power to move things is, theoretically, increased by about 60 times, and in the conditions as they affect soil movement in erosion, by about 30 times. The poor natural soil then may commence to erode immediately by the concentration of flow water caused by the road, but the highly fertile soil, because of its fertility, will easily withstand this first slight concentration. (See Fig. 4, Chapter 6.)

   The answer to this first problem of agriculture is the better planning of land subdivision, and it must be based on a knowledge of the natural flow movement of run-off rain so that the planning avoids causing unnecessary concentration of water flow. Rain falling on the limited land area of a farm is fairly uniform all over the farm, but when rain reaches heavy general run-off proportions, then the water moving over the land varies greatly in volume and depth. Water which has fallen somewhere else is flowing over every point of the land except the centre lines of the ridges and hills. The amount of flowing water is progressively greater from the ridge toward the centre of the valleys.

   Now, once boundary fencing as above is completed, large-scale clearing may be undertaken; preparation made for further subdivision and the land made ready for plowing and planting to crops and grasses.

   Every one of these operations in orthodox agriculture breaks the flow lines of water movement, causing new concentration of flow. The very poor soils show some erosion immediately; the highly fertile soil is completely unaffected.

   Every plow furrow that crosses a valley, every vehicle that moves on the farm, crossing even the flatter gentle valleys, breaks the natural flow line of run-off rain water and steepens its path to the valley, causing new and increasing quantities of flow. Side by side with this mechanical change in the conditions that affect water movement on land march others that directly and progressively change the soil climate. All, or nearly all, the trees may have been cleared, allowing drying winds to have a worsening effect on the soil, which then does not hold its moisture so well between rains. And the period of time that optimum conditions for soil-life development and plant growth exist is lessened. The dynamic forces of the soil are at first slightly, but then progressively, reduced.

   The poor soil shows the effect quickly; the highly fertile soil. is apparently unaffected. It may show no positive soil erosion effect for many decades.

   Reducing these damaging effects, general farming practices may be improving conditions in other ways. The growing of plants in the soil and the feeding of stock on the crops and pastures are in themselves the same processes that form and improve soil. If the balance of all factors generally has the effect of improving soil climate, then the soil will improve and remain stable.

   A property may be overstocked; concentrations of stock may firm the soil and at first even improve it. Then a real compaction may set in restricting the former depth to which suitable aeration extended. Beneficial soil life is restricted to the top inch or so of soil. The dead roots of the pasture grasses cannot form the best food for the most beneficial soil life, because this life cannot live without air. The fertility factor of the dead root is largely wasted, the current formation of new products is lessened and the soil is then deteriorating by fertility erosion. Less, moisture is absorbed in the soil, more water runs off with increasing velocities, carrying soil with it. Apart from the erosion which is caused solely by the artificial concentration of water flow, fertile soil must always suffer this fertility erosion before widespread soil erosion can touch it.

   Concentrated water flow will move almost anything, but fertile soil can be plowed badly, up and down hill, and everything wrong can be perpetrated on it, but it still will be little affected by soil erosion until the treatment has reduced its fertility, reduced drastically its life and the current formation of new food or humus. The forces tearing down its fertile structure must be greater than the forces building them before soil erosion can affect it.

   Some soils that farmers may believe are very fertile erode badly. But always such soils have lost their former power to produce year by year new or current humus. Among the many products of fresh humus is the gum-like substance which forms the crumb structure of fertile soil and resists movement. The good crops which they may still produce in good seasons, and the seasons affect them more and more, come from readily available minerals inherent in the original rock or produced in the past by the soil's former biological fertility.

   Land which once carried some of the most fertile soil on earth is now distinguished by its giant erosion gullies. It took decades of plowing, bad plowing and cropping or wrong management, to start the serious erosion. Many of the cultivating implements of agriculture are condemned by the terrible land destruction that followed their use, for example the mouldboard plow in the great corn belts of, North America, the disk plow in the drier wheat areas of America, Australia and Africa. It would, however, be just as logical to blame the destruction of land on a most popular tractor because it pulled the plow, destroying land much more quickly, as to blame this type of erosion entirely on the implements. The failure of agricultural education or the general attitude of some early farmers to the land, the mistaken belief that exploitative farming was good farming, the lack of farming experience and knowledge by the early settlers, the failure to adjust the best in European farming methods to the new conditions of the new lands, the cheapness and abundance of good land, the thoughtless and careless rush to produce for a profitable and expanding market--all these factors are causes of the erosion problems of soil that worry the nation and other nations today.

   Cultivation equipment, to be effective, has to produce a mechanical condition in the soil that permits crops to be planted, controls unwanted growth and allows the crop to grow, mature and be harvested.

   Cultivation according to how and when it is done can eventually destroy soil fertility and start serious erosion or stabilise, develop and improve soil far beyond its natural state.

   Continuous year-by-year cultivation to an even depth with orthodox mouldboard and disk plows is likely to form quickly a new artificial soil horizon that changes the soil climate and reduces soil fertility. The smashing and pulverising effects of many types of cultivation, if continued, change the soil climate by gradually sealing more and more with the first following rain, which restricts both the intake of moisture and air. The most desirable type of cultivation at the wrong time of the year is still bad. It promotes the rapid loss of moisture in summer and on the light soils in winter reduces the temperature of the soil.

   Cultivation that promotes the best conditions of moisture, warmth and air in the soil together improve soil climate and promote fertility.

   Any straight line cultivation or round and round the paddock plowing is tending to break the flow path of run-off rain, steepening its path and concentrating its flow. Acting and compensating against this though, certain types of cultivation, notably chiselling and ripping, may increase the absorption of rain and reduce flow. Again, if the balance of the factors improves soil climate, the soil improves and its stability is preserved. If the balance deteriorates soil climate the reverse is true.

   It is not so essential that soil never be treated in such a way as to deteriorate its climate as it is for the farmer to understand the process he is using, and its ultimate effect, if continued, so that he can keep the general balance always in favour of his soil.

   Some soil treatments or management processes which work against soil fertility may be necessary at times in the course of farming operations, but always the more fertile the soil the better it is able to withstand damaging treatment for a time. Various types of cultivation are necessary in farming enterprises and many cultivation processes are damaging to soil fertility. But just as surely, in my. opinion, cultivating processes can be a great aid in improving soil climate and soil fertility if the farmer understands just what he is doing.

   It seems that the aim must be to redesign every mechanical agricultural process so that it has the effect of improving soil climate. Then every other useful art and science of agriculture and property management will have greater benefit because each is applied or used on a fertile and improving soil.

   Soil climate is so vastly important because, apart from its influence on agricultural production, it is the dominating influence on the development of the soil-life communities. This life in turn is likewise very important, because its products, the products of its living and dying and reacting on the various components of soil, supplies the necessary nutriments for plant life. It is a necessary part or process of fertile soil. The more dynamically alive the better it is.

   The farmer should know that as soil dries out so the soil life dies out, but will regenerate again rapidly from its vital forces and eggs and spores when soil climate is again suitable. He should know that cold soil reduces the forces of soil life to a lower ebb; that moisture, warmth and air produce the climaxes of soil life; and, finally, that soil life feeds on every type of food, including other organisms of soil life, minerals and organic matter.

   When soil has been eroded and almost completely lost, soil life can be regenerated in the dead earth by cultivating and sowing grass and clovers with fertilizers to stimulate early growth, and by the introduction of stock. Some species of soil life are distributed by all classes of animals and birds from their rumen glands and organs, and the wider the variety of the stock the more complete and beneficial is the whole complex of soil life.

   Even without appreciating or knowing much about the soil life he cannot see, the farmer will know that his soil is as it should be when he can see that it contains a large and vigorous population of earthworms.

   During the early part of 1944 1 commenced to develop "Yobarnie". I was a well-informed and ardent follower of American soil conservation methods and these techniques soon dominated the appearance of the property. Many experiments were conducted on pasture and soil improvement, both with the strongly artificial fertiliser approach of our orthodox agriculture and the wholly organic methods. Both methods, when we irrigated, produced good-looking pastures, but we were never conscious of an earthworm population. I do not remember seeing, earthworms or their casts in the paddocks at that time, but no doubt there were some present. Some years later adjacent land was purchased and "Nevallan" was established. After two years of Keyline on this property, which was much more eroded than "Yobarnie", earthworms and their casts became so evident they could not be ignored. We commenced to take a great deal of interest in this remarkable phenomena. We dug, counted, measured and weighed earthworms.

   Suddenly they disappeared; there were no casts nor earthworms to be seen. We found the earthworms with the aid of a spade, deep down in the earth.

   Towards November they were everywhere again and ten times as many were casting on the surface of the ground. They had again disappeared by December, but at the end of March the following year they were in their millions and were seen by some of our largest parties of agricultural scientists as well as by more and more landmen. Now the earthworms were much larger. There were many more of the smaller earthworms, but the large ones--which we believed must be the older worms--were now over fourteen inches long. Many visitors both from Australia and overseas told us we had the largest population of earthworms they had ever seen. Other visitors said that they knew of only one area, the fertile Nile valley, which had a greater earthworm population than "Nevallan".

   However, the point is not the development of the earthworm population on "Nevallan", which could be another story, but their function in the development of soil. Visitors have said to me, "Oh, yes, the earthworms follow the good soil", and others just as positively, "Once the earthworms are introduced they make good soil". But we did not have any good soil on "Nevallan" when we started Keyline and we did not introduce earthworms there.

   I believe that the earthworm is merely a part of the life process which is soil. When the soil climate is slightly improved a few more earthworms breed and stay alive and active a little longer. At the same time, this applies to many other species of soil life which, although we cannot see them, increase in numbers by countless millions in a week. The minute forms of this life have a very short life cycle, but the earthworm, truly the giant of the beneficial soil life, may live to a great age. I have not yet found a reliable reference to the age to which an earthworm may live, but I have concluded that the largest of our "Nevallan" earthworms must be up to four years old now. There are large numbers in all sizes (and size may be a reliable indication of age), up to fourteen inches long in their shrunken, not stretched, length, with many over twenty inches long.

   Many species of soil life require no other food than the soil or earth particles themselves. All they require to perform their work of making soil is improved living conditions, i.e., improved soil climate.