With a good deal of truth it may be said that we have allowed our soils to degenerate chiefly because there have been too generous supplies of good soil everywhere over the face of the earth. The existence of these fertile areas, and particularly the discovery by Columbus, at an opportune time, of a few hundred million extra acres previously unheard of and unsuspected, served to make man's way easier. As long as this condition obtained, it was not imperative that man should learn how to provide tillable soils where none existed.
It is now time, however, that the truth be realized. We can recreate soil wherever good soil formerly existed, and we can do so by machinery. Any exceptions to this categorical statement will be found to result from human mistakes, as, for example, land made untenable by the silting of the streams that naturally would drain it, or desert sands robbed of both their water-holding clay and the water table conveniently near the surface. For the whole category of areas that have suffered merely water erosion, however severe, there is still the definite assurance that as good soil as ever existed upon them can be restored. Much the same can be said of areas damaged by wind erosion, or by excessive cropping and grazing.
Nature did not put precisely the same kind of soil everywhere. There has been a great variety of difference in soils because of the complex forces by which they were created. That we need not go into here, except to say that the one thing all soils had in common was organic matter in or on the surface. We need not be interested in the slightest as to whether the soil was what the scientist calls a podzol, a prairie, a chernozem, or just plain dirt; the significant thing about each of these, in the virgin state, was the quantity of organic matter it contained, which implies also the conditions under which the moisture supply would permit the maintenance of a certain amount of organic matter in the soil.
It is not even necessary that soil be of brunette shade in order to produce well, although soils made productive by Nature always reveal their quality through the presence in them of decaying organic matter, which is necessarily dark in colour. (The single exception to this statement—if indeed it can be called an exception—is the desert area to which irrigation water has to be supplied. Such soil is rich by reason of the suitable minerals which are brought up from the soil depths by water, which, on evaporation, leaves the minerals in abundance. The dependence of desert soil on irrigation really rules it out of this discussion.) Enough organic matter can be put into the surface at a single discing to make any ordinary soil productive almost immediately; yet the quantity of organic matter introduced at one time may be too little for its decay to influence the colour of the soil. This was true of the soil I farmed in 1940, with rye three to six feet tall disced in to serve as the organic source of nutrients for my crops. I could never detect any of the dark tint which is associated with organic decay, yet the crops behaved as if there were plenty of fertility in the soil.
The blackness of virgin soil is the result of a cumulative process more or less complex, since it involves repeated deposits annually of plant, and possibly animal, debris upon the soil surface — to which must be added the destructive effect of an innumerable biologic population which lived and died in this environment and contributed in turn toward its enrichment. The effects of the resulting black deposit in and just under the surface — not in an impassable layer several inches under the surface — kept all the water absorbed by the soil in the same zone in which plant roots would be searching for it. The supposition that for hundreds of years nothing had disturbed its surface does not satisfactorily account for the fertility of the soil. We have developed some useless theories in that field. Men have come to feel, for example, that centuries are necessary for the development of a productive soil. The satisfying truth is that a man with a team or a tractor and a good disc harrow can mix into the soil, in a matter of hours, sufficient organic material to accomplish results equal to what is accomplished by Nature in decades.
In Nature, long periods were occupied in developing the black OMP of the meadow or forest because the mixing in of organic matter was a task mainly for insects and worms. The soil surface was their home environment. They worked slowly but painstakingly, and they developed that first essential of all life, the health of the land.
This has been true, necessarily, of the natural formation of soils everywhere. The grasses of the plains developed thicker, blacker layers of organic matter in the surface because they were annual plants. They died down each autumn. New growth came up each spring. The dead plants accumulated, and were mulled over by the living things of the soil surface. Only a few years of this process were necessary to develop the tough turf the settlers found when first they undertook the gigantic task of ploughing it. It is not surprising that in many instances ten-ox teams were necessary for the purpose.
The forest did not lay down organic layers as deep or as black. Why ? Because the decay of leaves each year was more complete and the material was re-used in tree growth. The farmer who cleared the land got merely the " crumbs " from the forest's " table." It could not be otherwise.
With the halo of mystery thus stripped from the mechanics of natural soil building, it no longer appears impossible for men to create their own soils as needed, and where needed. It has to be remembered, too, that when the soil of an old forest site has been restored to a condition as productive as the one which originally existed, there will not be the necessity of waiting for stumps and roots to rot out, as was once the case, before the land can be handled profitably. Many a farmer of another generation found that, by the time these interferences were out of the way, the soil was no longer productive. The modern farmer has a big advantage in that he can simply disc in a crop of green manure whenever he chooses and withdraw a good portion of the products of decay in the first year's production. And the process lends itself to infinite repetition.
Historically, we are told, soils are very different in their origins. So different, in fact, that their adaptation to specific crops is affected. The more correct view is that these idiosyncrasies of soils were developed only after the original organic profile had been destroyed and most of the organic matter used up. On good virgin land, the chief production limitations are due to climatic factors rather than to the peculiarities of soil origins. My experience in growing sweet potatoes is a case in point: the plants had completed their growth in two months, rather than four, on land near Lake Erie quite outside their normal habitat. The presence of sufficient organic matter in the soil, a plentiful supply of water in the organic matter, and the prevalence of hot, sunny weather all combined to overcome any adverse factors. I had been told by a Virginian, a local buyer for a chain-store organization, that sweet potatoes could not be grown successfully in this locality. I was disinclined to believe him. When the crop matured, he bought part of it, paying about 25 cents a bushel above the prevailing market price for the best southern-grown roots.
Personally, I doubt whether one type of soil is any better suited than another to a given crop, provided each soil is supplied with an abundance of organic matter in the surface. Note the fact that a liberal quantity of organic matter is stipulated, and that it must be in the surface. If two soils so treated are subjected to similar climatic conditions, however different they may be in origin, their respective crops will be too little different to indicate a substantial superiority for either. In other words, sweet potatoes - definitely preferring sandy soils—will produce heavily on tight clays, provided first the clays have been richly endowed with a supply of organic matter in the surface. I have already produced parsnips in heavy clay so treated; the yield figured 1,220 bushels to the acre. Parsnips ordinarily are grown in sandy loam.
I am not prepared to say that the mere discing of organic matter into the soil surface is the complete remedy for all adverse soil conditions. There are too many unusual conditions of which I have too little knowledge. My acquaintance with soils is not broad enough to justify a complete generalization for all soils. However, unless we are prepared to question the universal application of theories and principles that have been proved by generations of use in other fields, we must admit the widespread applicability of this idea of surface-mixed organic matter as a remedy for many, if not all, of our soil troubles. Also, the fact that all applicable experiment station results support the idea gives additional weight to the contention I have advanced.
We have no implement that is well suited to the incorporation of organic matter into soil surfaces under all conditions. The disc harrow is a good one to use under a great variety of conditions, but even it has its limitations. It cannot be used in soil that is very stony, even though it would successfully follow the plough in such case. It is difficult to manage on hillsides. Unless special techniques in its management are used, the disc harrow does not leave a smooth surface. Some of these difficulties could be overcome by the use of power-lifting devices, but such devices are of no use to farmers who have only horses. Yet, until somebody invents a better implement, the disc harrow is the one tool that can be substituted for the plough in the successful preparation of land (not in turf) for cropping. Its use for this purpose, however, is so different from its traditional role of smoothing up after the plough that a few hints should help the farmer who wants to try it. Such a routine as the following will work best:
| (1) | Be sure the discs are sharp and free from rust. Have the entire implement in good working order, all grease cups or other oiling arrangements fully supplied with lubricant. This last is especially important, for the disc harrow was not designed for heavy work like land breaking. Work of this kind will subject it to very unusual strains, so it should be kept perfectly lubricated all the time. |
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| (2) | Use only the front section of the implement as long as you are trying to cut into the soil. Detach the rear section after reaching the field, for it will be useful in the final work of smoothing up. If it is allowed to follow along while the front section is trying for depth, its weight will tend to keep the front section from running deep enough. |
| (3) | Weight the front section heavily. This is where some of the extra strain comes in. The plough is so designed that it naturally seeks a certain sub-surface level and therefore does not require weighting. The only force that urges the disc harrow into the ground is due to gravity. Weight adds to this force. |
| (4) | Set the discs to cut in—how much is difficult to say - but try adjustments at different angles to see what the effect is. Do not be surprised, though, if, on the first trip over a field, you cannot see that the discs have cut in consistently. Usually they will have cut in slightly, even though the dirt is not thrown up suffciently to be seen. |
| (5) | One important procedure to observe in putting in a tall, strawy crop, like rye, is to lay it all down in one direction, then cut across it at an angle. This serves to cut the straw into lengths that can be worked into the soil easily. For this work, of course, the discs need to be sharp. Also, there are limits to the amount of rye that can be managed by the disc harrow, however sharp the discs may be. Experience is the best guide here; no rules can be laid down. |
| (6) | It may be that a clay soil in a very dry condition will not yield at all to the discs. In that case, it will probably help to run over the field once in any case. This will ride down the green manure crop so that it will lie closer to the surface. Some improvement in moisture content of the surface soil should result. Later, say in a week, a second attempt to cut into the surface is likely to be successful. Failing this, wait for rain. |
| (7) | Farmers who have always used double-disc-harrows may need to be told that when the front section alone is used it should always be lapped half-way each time in order to leave the land smooth. This is very important if the discs are cutting in; less so, of course, when they are not. |
| (8) | Following the routine outlined below will make it
possible for the operator to do a smooth job, or at least a
smoother job would result than if this method were not
followed. You may be able to work out a better plan for your
own situation. This is offered as a suggestion, assuming a
square or rectangular field:
Decide first which way you wish to make all turns, With some outfits, left turns can be made better; with others, the turn is easier to the right. Since all turns are to be the same, it is necessary to determine this in advance. Start along one side of the field and follow the boundary to the limits of the field. Turn along the border and follow it about four or five widths of the harrow; then turn and follow a line parallel to the first direction to the opposite limits; return to the beginning. Repeat by lapping the harrow a half width toward the middle of the field as you follow the earlier track. At the ends no lapping is possible, since in going one direction the previous cut of the implement is to your right, or in going the opposite direction it is to your left. At the ends you must make this change of sides. |
In the above three paragraphs you have the simple directions for what may be called a " spiral " discing routine. If you begin by crossing one end of the field, then your progress is very gradually toward the opposite end, by these crosswise trips that inch over one half the width of the implement each time.
Also, after about ten times around the " spiral," you begin to catch up with the forward side of the original first-round track. At this point you may wonder what to do. The answer is to continue just as you began, lapping one-half width all the time, until you reach the opposite end of the field with the forward track. Then you will have double disced the first ten rounds and the last ten rounds, while all between will have been quad-ruple disced. In other words, most of the surface will have been stirred four times with the discs, but the end strips will have been stirred only twice.
Perhaps, by the time you have gone over the entire field once in this fashion, it will be in proper condition for the final smoothing. However, I have usually found that, in order to prepare land sufficiently well to make the use of cultivating equipment possible, it is necessary to repeat this process exactly as indicated, except that the disc is run crosswise to the direction taken by the original work. Of course, if the routine just described was preceded by the operator's going once over the area and riding down the green manure crop, the quadruple discing operation will have reduced this material to six-inch lengths. In that case, it is likely that once or twice over with the reassembled harrow may serve to complete the seed-bed sufficiently to make planting possible. Do not expect it to look as smooth as it would if the land had been ploughed, even after you have done all the smoothing possible. And there may be at best some rubbish visible here and there. Neither the lack of perfect smoothness nor an occasional bit of debris will be fatal to the use of ordinary equipment; though in planting it probably will be necessary to delay the work occasionally long enough to remove from planter shoes accumulations of the rubbish. A little patience in this respect will be richly rewarded later, for you will find that the crop will be much less subject to drought damage, will require absolutely no nitrogen fertilizer, and will yield out of all proportion to customary standards. This will apply, regardless of the kind of crop grown.
You may or may not have to smooth the final work of the disc with a drag. Certainly you will not have clods to contend with. Compacting is likely to be important if the weather is dry. However, the disc harrow may be used for this purpose, not as effectively as a regular roller or corrugated compacting imple-ment, but with the discs set straight and heavily weighted it does a fair job.
One caution should be given concerning cultivation. I came near ruining one corn crop because I failed to discover that there was enough uncut straw in the surface to lift slightly almost every hill of corn as the cultivator passed. The rye on this field had been six feet tall. It had proved impossible to work it in at all, and much of it lay there, not even cut into sections. If you should have that same condition to contend with, delay the first cultivation until the straw has had time to disintegrate sufficiently for it not to interfere. This will not require long, providing a little rain falls. If the weather is dry following the planting of the corn, two or three weeks may be required. Success in this respect is wholly a matter of careful observation and management.
Of course, if you encounter such conditions as have just been described, you cannot hope to plant the area by means of ordinary equipment. It was to make planting possible in such a surface that I devised the pressure marker. Planting after this device was used had to be done by hand, but the manner in which the crops grew fully justified the hand method. It can readily be seen that, if the planter can expect several times the customary yield per acre from soil so re-created, he is justified in conceding something to painstaking care. Again, if it is possible, by renewing the soil with green manures, to cut the usual acreage to one-fifth, one-third or one-half, the concession is scarcely a concession at all.
Eventually, it is to be hoped, suitable implements will be devised and put on the market. Meanwhile, I anticipate modifying to some extent the plans I followed in 1939 and 1940. Instead of growing green manure in quantities sufficient to make incorporation impossible with the disc harrow, I hope to spend more than one season in getting the land ready for crops; then, after working a two- to three-foot rye crop in early in spring, some summer crop will be seeded to be put in later—to be followed by rye again. This would involve two green manure crops each year. Not many such short crops would be required, it would seem, to make the soil begin to look black again. And, treasonable as it may seem, I hope that while this routine is in progress each crop will be accompanied by the germination of multitudes of weed seeds. Discing in immature weed plants with each green manure crop may be an excellent way to reduce weed growth. More is said about this in a later chapter.
It may easily be that some land will prove so refractory to discing that it will not be possible to work in the first crop of green manure at all. This event need not stop your efforts. Do not plough it in. Or, if you do plough it in, plough the land again immediately, and a little deeper. If you do plough twice, you will have created a superior soil situation by that means, for the second ploughing will have returned to the root zone your mass of green manure. In this position the disc harrow will be able to reach and cut it. To your delight you will discover that no clods form in connection with the work, so the follow-up operations usually necessary can be cut quite short.
Double ploughing is not a new device. Friends of mine recall that the farmers of a previous generation often ploughed down clover in the fall, then ploughed the land again in spring for potato growing. Apparently the method worked well. However, much decay of the clover must have occurred during the winter, and the leaching away of much of the products must have been inevitable. Moreover, the decay of this material made it possible for the farmer to do a much neater job of ploughing in spring than might have been possible had the land been ploughed twice in quick succession. Many a farmer who decides to plough down a heavy green manure crop and follow up immediately with a second and slightly deeper ploughing will be thoroughly disgusted with the idea before he has gone many furrows. The appearance of the resulting surface will be disheartening to farmers who have always taken pride in the neatness of their ploughing.
The trouble here is not the appearance of the surface but our notion of what constitutes beauty. Few people realize how thoroughly we have become enslaved by the idea that nothing effective can be done towards preparing land to grow crops until the land has first been ploughed. Ploughing has been accepted as axiomatic — a necessary prelude to every other operation. Even though the work of the plough has for many years been associated with the deterioration of our land, we have still not awakened to the fact that to solve the problem, we must cease ploughing; or, if we wish to continue to use the plough, we must do the work in a different way. The methods we use, whatever they be, must produce a surface that is filled with debris that will rot. Let the surface of the soil wear a " beard " of exposed material, if need be. That condition will eventually become beauty in the soil. " Handsome is as handsome does " is not a new saying. It is particularly applicable here, for debris-filled soil alone is capable of the highest quality yields. The ancestry of a soil is a very minor matter in comparison with the present ability of that soil to supply to hungry roots a soil solution enriched by abundance of the products of decay.
An alternative to double ploughing land that cannot be managed by discing is to leave the area wholly undisturbed. This may seem an acknowledgment of failure, but the matter should not be prejudged. Much will happen to an intractable soil while the crop it has produced is decaying. The decay of a green manure crop, in place, will of itself serve to start a heavy soil surface on its way toward granulation. When granulation has proceeded sufficiently, a clay soil can be worked like sand. Moreover, if the crop in question produces seeds— which any annual crop will do—it will reseed itself naturally; and, without any work whatever, the farmer will have a second, spontaneous crop of green manure to reckon with. This second crop will be very easily managed when the time comes to disc it in.
It has to be admitted frankly that the preceding paragraph is a deduction from the known effects of the practices described. For this reason, the conclusion may be considered vulnerable. My best suggestion is that anyone who is inclined to doubt the feasibility of the plan advanced should try it on an area of supposedly unmanageable clay. I have seen clay become so friable, under conditions that were comparable to those suggested here, that it could be raked about like sugar. The same clay, before treatment, was so solid that a sharp spade, with a man's weight upon it, was scarcely enough to make an impression upon the surface. I am certain, therefore, that further experimentation will sustain my contentions.
The abandonment of the first season's work in order to let Nature cure the ills of the turf may seem a waste of time. The economy of such a procedure must await confirmation until the outcome of subsequent crops can be observed. The eventual result will contain its own proof. And my guess is that those who know soils best will be the last to doubt the eventual out-come, for the renovating effect of decaying organic matter, which induces granulation of the soil, is well known and accepted.
The only new thing about it is the method proposed for securing that effect.
Doubtless, the creation of soil where none now exists, through incorporation into the surface of materials grown upon the particular area, presents many difficulties not touched upon in this chapter. The idea is entirely too new to have been thoroughly investigated in all of its ramifications by a single unsponsored student in a single season of work. But it is extremely doubtful whether the actual recreation of soils presents any technical difficulties which cannot be surmounted. The only requirement for the establishment of a new tillage system, apparently, is investigation along one or both of two lines: first, the adaptation of our customary use of existing surface-stirring implements to the job of incorporating liberal quantities of green manure; or, second, the invention of new equipment capable of disposing of all organic matter by surface mixing. No further time should be lost in delaying the accomplishment of one or both of these objectives.
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