Soil Culture / Containing a Comprehensive View of Agriculture, Horticulture, Pomology, Domestic Animals, Rural Economy, and Agricultural Literature

by J. H. Walden

Another fact: take a load of manure, dry it thoroughly, and weigh it. Then moisten it and apply it to the soil, and it will increase the weight of vegetation from ten to thirty or forty times its own weight when dry, and yet most of that manure may still be found in the soil. Hence it can only feed plants in a very limited degree. Its action must be on air and water, or the control it gives the soil over those elements.

It is also matter of common observation that soil well manured, will continue moist for a long time after similar land by its side, but which has not been manured, is dried up. Hard coarse soils dry up very quickly, while soft, mellow, and friable ones will endure a long drought. The gases and moisture generated by the decomposition of manures produce this mellow state. Hence the necessity of having that decomposition take place under the soil, or of plowing in the manure.

Another important fact bearing on this question is, that what are regarded very poor soils, such as light sandy or gravelly land, will produce good crops in a season remarkable for the frequency of showers. On such soils crops are from twice to four times as large, in a wet season as in a dry, and yet there is an addition of nothing but moisture, and in such a manner, as not to have it stand and become stagnant among the roots of the plants.

Yet another evidence is in the strength of clay soils. A hard clay is very unproductive. But so disintegrated that plants can grow in it, it produces a great crop. This is because clay is of so close a texture, that when mixed with manure, turf, sand, or muck, although friable, it retains more moisture, than sand or ordinary loam. This is the reason of the superior fertility of land annually overflowed with water, as Egypt in the vicinity of the Nile. It is not that the Nile brings down deposites from the mountains of the Moon, so rich above all that is in the valleys below. The entire weight of all that a river deposites on ten acres would not equal in weight the increased vegetation of a single acre. The cause of the increased fertility is the fact that the deposite is so fine that it prevents rapid evaporation, and thus causes the soil to retain moisture for the large growth, and maturity of the plants.

One more evidence is found on our sandy pine plains. Our common forest-trees, as beech, maple, elm, or linden, will not flourish there. Such land will produce comparatively no corn, oats, or wheat. But rye that stands drought better than any other grain, grows tolerably well. But such plains always produce an enormous growth of pine timber, hardly equalled in the number of cords to the acre, by the heaviest-timbered land of the river bottoms. Why is this? Does a maple need so much more food than a pine, or is it in the habits of the trees? It is not in the richness or poverty of the soil, but in the adaptation of the trees to reach and appropriate moisture. The roots of the maple and beech, spread out near the surface of the ground. And it being a light, porous, sandy soil, it does not retain moisture enough to promote their growth. But whoever notices a pine-tree that has been turned up from the roots by the wind, will see that the roots run down almost perpendicularly ten or fifteen feet into the sand. There they find plenty of moisture and hence their great growth. This principle explains the comparative productiveness of all soils.

A soil composed of light muck, or a kind of peet-soil, will dry up soon. There is nothing to prevent rapid evaporation; hence it is always unproductive, for want of suitable moisture. Mix with it clay, to render its texture more firm, and it will retain the moisture, and be very productive. Clay alone is too solid to retain moisture; it runs off, as from a brick. Mix sand with it, and it becomes mellow, and retains moisture, and produces great growth. Sand allows so free and rapid an evaporation that it is unproductive. We say it leaches and is hungry, and so it is, because it has little power to retain water. Our manures do it good, only as they are calculated to aid it in controlling moisture. If we apply a light manure as we would to clay, it is comparatively useless; it adds no firmness to the texture of the soil, and hence does not increase its capacity for controlling water. On such land, the only good that manure does, is while decomposition is taking place in the soil, it renders it more moist, and hence more productive. Apply clay to such a soil, and it will increase its firmness and consequent capacity of retaining and appropriating moisture, and thus render it highly valuable. Dry straw manure is sometimes said to dry up land, and ruin crops. So of turf in a dry season. In a wet season they greatly increase the growth of crops. Now they contain just as much food for plants in one season as another. Hence a soil too easily impervious to the atmosphere, will be a poor soil, that is, will produce poorly, simply because it has no power to retain the necessary moisture.

We suppose these facts and reasons to establish our theory, that the principal benefit of manures, and of mixing different soils, is in the control they give over the moisture and the atmosphere. Hence the greatly increased crop of clover from the application of three quarters of a bushel of plaster to an acre. The increased weight of clover on five square rods, would outweigh the plaster applied, and still that plaster remains, in almost its full weight, on the soil. This principle explains the benefit of mulching trees, plants, or vegetables. This is the best means of preserving trees, the first year after transplanting, and of securing a great growth, of any kind of shrubs or plants. This may be done with common straw or leaves. Now wherein is their utility? Not in the nourishment they afford the plants, but in the fact that mulching so covers the surface as to prevent rapid evaporation. In such cases, it is the more abundant moisture that secures the greater growth.

Hence the first study of a soil culturist should be to ascertain how he shall so mix and manage the materials at his command, as to cause them to retain moisture for the longest time, without leaving water to stand about the roots of his plants. On this depends the whole importance of deep plowing and ditching. On this theory we may also account for the fact that certain plants prefer a certain kind of manure to all others. It is that those plants act in a certain manner on the soil requiring a specific action of manure to enable it to appropriate moisture and tax the atmosphere for their growth. This theory explains why too much manure is bad. Not because we give too much food to plants, but because excess of manure dries up the land. But whatever theory we adopt, we all agree in the utility of fertilizers. And the experience of practical farmers is of more value in aiding us to reach right conclusions, than all chemical essays on the subject that have ever been written.

MARL.

This is one of the best distributed and most universal fertilizers. Marl proper contains nearly equal proportions of clay and lime. Sand-marl is spoken of, in which sand and lime are the main ingredients. Clay-marls are to be applied to sandy and gravelly soils, and sand-marls to clayey soils. Shell-marls are very valuable, and seldom contain clay. Marls may easily be known, even by those not at all acquainted with chemistry. Apply any mineral acid, or even very strong vinegar, and if it be a marl, an effervescence will at once be observed: this effect is produced by acid upon lime.