Soils, manures, and preparing the soil—plowing, harrowing, &c.—are the three great subjects in any good agricultural work. We shall treat this subject under the following divisions:—
1. The substances of which manures are composed.
2. Preparation and saving of manures.
3. Time and modes of application.
4. The principles of their action upon plants.
Manures are of two classes—called putrescent and fossil. The putrescent are composed of decayed, or decaying, vegetable and animal substances. The fossil are those dug from the earth, as lime, marl, and gypsum. All vegetable substances not useful for other purposes are valuable for manure. Rotten wood, leaves, straw, and all the vegetable parts of stable manure, and any spoiled vegetables or grain, are all valuable. At the South, their immense quantities of cotton-seed are a mine of wealth, if properly prepared and applied as manure. Animal manures consist of the animal parts of stable manure, dry and liquid, parts of bones, brine, spoiled meat, kitchen slops, soapsuds, and all dead animals. In decaying, these substances all pass through a process of fermentation. Left exposed without suitable care, they become unhealthy and offensive. It is probable that a large share of the diseases suffered in the rural districts are caused by these impurities; and the impossibility of keeping large cities free from these substances is the cause of their increased mortality. In the country, a little timely caution and labor, in removing these substances and regulating their fermentation, would save much sickness; while the labor would pay a larger per-cent. profit than any other performed on the soil. No manures should be allowed to ferment, or decay, without being mixed or covered with enough common earth, sand, peat, or muck, to retain all the gases and exhalations of such putrescence. The smallest quantity that will answer is one load of earth to two of the decaying substances. The proportions reversed would be better: put one bushel of lime to two loads, two quarts of ground plaster, and half a bushel of ashes, and you have the very best compost heap. The following are brief general rules for the preparation of manures. It is always most economical to feed cattle in the stable or under cover, and never have manure exposed to the weather. But if cattle must be fed outdoor, let them be fed in a yard, lowest in the centre, that the liquids and washings may run into the centre, and be absorbed by straw and litter. Put manure on the land, or into heaps for compost, before very warm weather. Always feed sheep under cover, and keep their manure from rain; heap it together with earth in the spring, or apply it to the soil at once. Manure thrown out of a stable should be kept under cover, out of the rain, and not allowed to heat in winter; its best qualities are evaporated by fermentation in the yard. Manures often rained on in winter, or left in large piles without intermixture of earth, lime, plaster, and ashes, will ferment and waste. Construct your stables so that the liquid manure will run into a vat filled with earth; muck is best. Experiments have shown that the liquid manures are at least one sixth better than the solid. A gentleman dug a pit, thirty-six feet square and four feet deep, and walled it in on all sides. He filled his vat from a cultivated field, and so constructed his sewers from the stables adjoining that the urine saturated the whole. He kept fourteen head of cattle there for five months, allowing none but the liquid part of the manure to pass into the vat. He spread forty loads of this on an acre. For ten years he tried equal quantities of this and well rotted and prepared stable-manure, side by side, in the same field, and obtained great crops; but in no stage of their growth could he see that crops on the land manured from the stable were any better than those that had received only the soil from the vat. The latter were quite as good as the former. The contents of his vat manured seven acres, or half an acre to each creature stabled. The result is proof that one cow discharges urine sufficient in five months to manure abundantly half an acre of land. Save the solid manure equally well, and a cow will make manure enough, in five or six months, to increase a crop sufficiently to pay for herself. It is certainly safe to say, that a careful man can make the manure of a cow pay for her body every year. Is not this an important branch of farming operations? Few pay sufficient attention to it. Fowls should roost where their droppings may be mixed with common garden soil or loam. The manure from each fowl, carefully saved and judiciously applied, will pay for its body twice a year. The hogstye may be very productive of manure, one fourth better than that from the stable. Connected with your hogpen, have a yard fifteen feet square for every five hogs; let that yard have no floor. Throw the straw out of their sleeping-room frequently to make room for new; throw into the yard, also, all sorts of weeds, refuse vegetables, corn-husks, peapods, &c.; also the dirt that will naturally accumulate in the backyard of a dwelling, including sawdust, fine chips, cleanings of cellars, scrapings of ditches, and occasionally a load of loam, muck, or clay—and six loads of manure to each hog may be made, that will prove far better than any stable manure; it has been known to produce fifty bushels of corn to the acre, when stable-manure produced but forty bushels. Old wood, brush, and chips, should never be allowed to remain on uncultivated, useless land. Wood throws out the same amount of heat in decaying as it does when consumed as fuel. The action of that heat on the soil is highly beneficial, retaining it long in a mellow state: hence, all wood, too old to be of value for any other purpose, should be put in heaps, covered up till decomposed, and then applied to the soil, as other manures. For potatoes or vines, but especially melons, it is preferable to any other manure. Nothing is so good for muskmelons as old chips from the woodyard. Leaves of fruit and forest trees are also very good; blood and offal of animals, hair, hoofs, bones, horns, refuse feathers, woollen rags, mud from sewers, rivers, roads, swamps, or ponds, turf, ashes, old brine, soapsuds, all kinds of fish, oyster and clam shells—all are valuable, and no part of them should ever be thrown away or wasted; they are all good in compost heaps, or applied directly to the soil. Bones are best ground, but may be used whole, pounded, or chemically dissolved, or mixed with alternate layers of fresh horse-manure, they will be decomposed by the fermentation of the manure (see "Bones"). Perhaps there is as much imprudence in wasting manures as in any part of American domestic economy. One who leaves his stock without care, and so exposed to the weather as to lose half of them and injure the others, is not fit to be a farmer; yet, many waste manure that would produce plants for man and beast, of far more value than the loss of stock complained of, and yet no one notices it—it is a matter of course, exciting no surprise. Wastefulness in a family, if it be of bread, flour, or meat, is considered wicked and impoverishing; while ten times that amount may be wasted in manures, that would enrich the soil, and excite little or no disapprobation. We hope the agricultural periodicals will keep this subject before the people, until these mines of wealth will no longer be neglected or wasted.
Application of Manures is a subject that has been much discussed, and respecting which, intelligent agriculturists differ materially. Some apply them extensively as a top-dressing for grass lands. This does much good, but probably one half of their virtues is lost by washing rains, and by evaporation. A better way is not to keep land down in grass long at a time, and, when under the plow, manure thoroughly. We knew a piece of light land that annually produced half a ton of hay per acre. The owner plowed it up, raised a crop, put a moderate quantity of stable-manure, and ten loads of leached ashes to the acre. We saw it in haying time, the third season after it had been manured and subsoiled and seeded down, and they were then taking fully three tons of timothy hay from an acre, which was the quantity it had yielded three years in succession, without any top-dressing. If a top-dressing of manure is to be applied, harrow the land quite thoroughly, and always apply the manure in the fall—it is worth twice as much as when applied in the spring. The rains and snows of winter cause it to sink into the soil, while the heat of spring and summer evaporate it. A mixture of plaster, lime, ashes, and a very little salt, sowed on meadows, immediately after haying, secures a good growth of feed, much sooner than it will come on other meadows. It also increases, quite considerably, the hay crop of the following season. It is a universal rule not to allow manure to lie long on the surface to which it is applied, before plowing in. Place manure in heaps, as large as will be convenient for spreading, and spread it just before the plow. Never spread manure one day to be plowed in the next. When manuring in the hill, have the planters follow the manure-cart. In manuring potatoes in the hill, drop the potatoes, and put the manure on them and cover at once. In a dry season, the yield will be double that of those planted in the usual way. For fall grains, plow in the manure, just before sowing the seed. This is better than plowing it in under the sod. If the land be not sod land, and you can plow the manure in only deep enough to cover it, and then, just before sowing the seed, plow again very deep, the effect is excellent. Apply manure to land in the fall, or just after harvest, and plow it in, let the land remain till spring, and then plow deep, and you get the best possible effect. On an onion crop, manure does the most good on the surface. On those raised from sets, or on any onions, after they get large enough to give room, put fine manure enough to keep down all weeds, and it will double the crop.
Gypsum is better sowed than in any other way. Mixed with a little lime and salt, or wood-ashes and salt, the effect on corn is better than from either alone. To hoed crops apply these articles twice, and always by sowing, and not by putting it around or upon the hills; the effect is much greater sowed, besides the labor that is saved. In applying guano, do not allow it to come in contact with the plants, as it is apt to destroy them.
It only remains to consider the principles on which manure acts upon soils, and produces growth in plants. The action of manure on the soil, by which it is enabled to retain and appropriate moisture, constitutes its main, if not its whole benefit. It may afford a stimulus to the roots of plants. Even the specific manures, that are supposed to supply organic matter to particular plants, may impart their benefits by their action upon the air and water. Facts are certainly at hand to show that the great and leading benefits of manures are in their control of moisture, and where that control is not needed, plants get a great growth on what we call poor soil. No manures, either fossil or putrescent, afford any considerable food for plants. Vegetation receives its growth mainly from water and from the atmosphere. Facts in support of this theory are abundant.
A trial was made to ascertain whence comes the matter of which a tree is composed. A quantity of kiln-dried earth was weighed and then put into a tight vessel. A willow shrub was also weighed and planted in that earth, and the vessel covered with perforated tin to keep out the dust; for a year and a half it was supplied only with pure water. The tree was then taken out, and found, by weight, to have gained one hundred and sixty pounds. The earth was then kiln-dried, as before, and weighed, and its weight was found to be only two ounces less than it was a year and a half before, when it was deposited there. The tree, then, must have received its growth, not from the soil, but from the water or the atmosphere, or both.