MANURES AND THEIR APPLICATION.

BY SIMON BROWN AND JOSEPH REYNOLDS, M. D., CONCORD, MASSACHUSETTS,

NATURE is always just; she never requires more of her workers than she furnishes them the means to accomplish. She requires the soil to produce plants only in proportion to the plant food she supplies to it. How does she manage with the trees of the forest? The seed is dropped upon the soil and comes up a small and tender plant, requiring but little food. Its foliage is annually dropped about its roots to protect and, by its decay, to nourish them. As it increases in size it yields more foliage, a large portion of whose substance is made up of the gases of the atmosphere condensed in the vessels of the leaves, and thus conducted to the earth. The increased amount of food which the increasing growth of the tree annually demands is thus, by its own action, annually supplied, and the supply is always in advance of the demand, so that when the trees have become too large, the mould is often accumulated to a great depth. In ancient forests, whose monumental trunks stand as landmarks of the centuries, the amount of nourishment which they require is inconceivably great; but the masses of foliage, the decaying limbs, and the broken boles decaying in the soil, supply them with abundant food. How wonderful is this process of nature, by which the supply is increased in proportion to the demand! This is true vegetable philosophy. Says Stockhardt, “Good farming consists in taking large crops from the soil, while at the same time you leave it better than you found it." This is what nature does in the forest, on the prairie and natural meadow, until man interferes with her operations. His method is wholly unlike hers. He plants a hundred apple trees upon his field; he cultivates the soil, and perhaps manures it while they are small; when they have become large enough to yield a hundred barrels of fruit, and at least a hundred barrels of leaves, he carries away the fruit, and the winds scatter the leaves. Here are two hundred barrels of vegetable matter annually removed from the soil. Could this amount of vegetable substance remain and decay upon the soil, he might reasonably expect its fertility to be sustained. But, no! He expects the soil to yield the annual crop of fruit and leaves, and to supply, in addition, the material for the increasing growth of the trees; and the larger they grow the less cultivation he gives them, and the less manure he supplies to the soil. He takes two tons of hay from his acre of virgin soil. Can he reasonably expect another crop as large unless he applies something to protect and nourish the roots of the grass? He takes two tons of stover and fifty bushels of corn from his acre. Will he take as large a crop the next year? Unless the supply returned to the soil be in some proportion to the demand made upon it, the most fertile soil will become exhausted. A virgin soil, in which a large quantity of humus has been accumulated, may endure such a drain for a few years, but the rich prairies of Illinois, under continual cropping, are yielding an annually diminishing harvest. Even the valley of the Nile and the cane-brakes of the Mississippi, unless renewed by the deposit from the overflowing water, would in time lose their fertility. This theory is confirmed by universal experience. In the new soils of the eastern and northern regions of our country scarcely two or three crops can be taken from the land without convincing proof of the truth of this philosophy. In all this re

gion the soil, except upon the river bottoms, is comparatively thin and sterile, and the effect of every demand upon its resources, like that of a demand upon the resources of a poor man, becomes at once apparent. The great law of good husbandry is, to return to the soil an equivalent for the crop taken from it. By rotation of crops, and by deeper ploughing, tolerable crops may be obtained for a longer period, but the unproductive and deserted fields in some of the northern States and in the older southern States show that this is only a battle with time, in which time is sure to win.

We arrive, then, at the conclusion that there can be no good farming without manure. In northern climates there is an additional argument for the use of manure. Many of the most valuable crops require naturally a longer season for their growth and maturity than the climate allows, and it becomes necessary to push them forward by stimulating manures.

COMPOSITION OF MANURES.

Such being the facts, it is obvious that the manure heap is the bank from which the farmer must draw his working capital. What, then, is manure? We have said it is plant food-any substance upon which the plant feeds in the soil. Anything which the plant derives from the atmosphere, although it contributes to its nourishment, is not denominated manure. We confine the term to substances applied to the soil. The term is said to be derived from manus, the hand, and is confined to substances applied to plants by the hand. The food of plants consists, first, of carbonic acid, or carbon combined with oxygen. By this chemical combination carbon is rendered capable of being taken into the vessels of plants. The framework or chief bulk of all trees and plants is composed of carbon, and, as it decays more slowly than most of the other components of vegetables, it is left in the process of decay more or less free from all other elements. The bulk of all the solid excrement that passes through animals consists of carbonaceous matter. Starch, gum, sugar, oils, and woody fibre consist largely of carbon. Peat consists of decayed vegetable matter, chiefly carbon, combined with earths, acids, and salts. All the substances composing the compost heap, whether animal excrement or decayed vegetable matter, as muck, grasses, straw, beans, vines, fruits, grains, seeds, or other vegetable growths, consist largely of carbon, either combined with oxygen, or rapidly coming into a condition that will enable it to combine

with it.

Second, Salts. Various salts enter into the composition of plants, as the salts of lime, potash, soda, silex, magnesia, sulphur, iron, and manganese. Nitrogen and hydrogen also are important elements of plants, but as they are extremely volatile they are applied in the form of ammonia, which consists of these two gases. Ammonia is never found in plants, but is decomposed either in the soil or in their vessels before its constituents are appropriated to their use. These salts are all found in the secretions of animals, especially in the liquid secretions, being derived by them chiefly from the vegetables on which they feed. Ammonia is abundant in animal secretions, being formed in them by the chemical union of hydrogen and nitrogen. The elements of ammonia not only enter into the composition of plants, but they operate as stimulants to their secreting and assimilating vessels. Deçaying animal substances, as flesh, hair, wool, feathers, skin, and gelatine, yield a large amount of ammonia, it being formed in the process of putrefaction by the union of their nitrogen with the hydrogen of water. All these salts are also found in the soil, the source from which they are ultimately derived by animals. By salts we mean earths, alkalies, and metals, chemically combined with acids, as carbonate and sulphate of lime, sulphate and muriate of potash and soda, silicate of lime,

sulphate of iron and manganese, &c. These all come into the category of plant food, and are essential elements of manures.

Third, Acids. These are important elements in manures. They are sel dom, with the exception of carbonic acid, found in a free state, but combined with the earths, alkalies, and metals. Their chief use appears to be as solvents for these substances. Salts compounded of them enter sparingly into the composition of vegetables. The acids themselves are believed by some vegetable chemists to be decomposed, and to enter into new combinations, thus assisting to form the acids found in the fruits and juices of many plants.

Fourth, Gases. Another important element of plant food, and consequently of manure, consists of various gases combined with the soil, or dissolved in water. They are sulphuretted hydrogen, consisting of sulphur and hydrogen; carburetted hydrogen, consisting of carbon and hydrogen; phosphuretted hydrogen, consisting of phosphorus and hydrogen; and carbonic acid gas, consisting of carbon and oxygen. The sulphuretted and phosphuretted hydrogen occasion the peculiar and offensive odors given off by manures in a putrefying state. Ammonia exists in manures in a gaseous form, except when combined with sulphuric or other acids, or with carbonaceous or aluminous substances, which have the power of condensing and retaining it.

Fifth, Water. Water, either pure or in combination with acids or alkalies, is the universal solvent employed by nature. If pure water cannot dissolve a substance, nature adds an acid or an alkali, and sometimes a third substance, to enable it to effect the solution. Water cannot dissolve silex, but, by first dissolving a quantity of carbonate of lime, it becomes able to dissolve silex, and form silicate of lime. Water contains, in solution, earths, alkalies, acids, and gases. It is everywhere present when animal or vegetable growth is going on, supplying to the vessels of their organs, in that state of minute division which can be effected only by solution, the materials which they require to construct their different tissues. Besides this, it enters largely into the composition of the blood and juices of all organized beings, and readily allows itself to be decomposed when either its oxygen or hydrogen are wanted.

The above-named substances, viz: carbon, salts with alkaline, earthy and metallic bases, sulphur, iron, manganese, acids, gases, and water, are the principal elements of manures. They are found in different proportions in different manures, and are rarely all found in any one manure. The different effects of different manures is owing to this fact, as well as to the difference in the soils to which they are applied. Carbonaceous manures applied to a soil consisting largely of humus will produce but little effect upon the growing crop except as a mechanical means of lightening the soil. Such soils require alkalies or matter containing nitrogen. On the other hand, sandy soils, which are deficient in carbon, are greatly benefited by manures containing a large percentage of carbon. Hence we may learn the advantage of mixing soils containing different elements. The peaty soil does not afford the silex and lime needed to give firmness and strength to the culms of grass and grain. The sandy soil does not furnish the carbon needed to construct their growing frame work. A mixture of the two will furnish all the materials needed. Manures containing a large proportion of nitrogen stimulate plants to a large and vigorous growth. Those containing phosphorus, or phosphate of lime, contribute to the size and plumpness of the grain and seed-hence the benefit of combining them both in the culture of the garden and field. That may be considered a manure which supplies any want of the soil, or of the growing crop. But a perfect manure is that which supplies all the wants of all crops in all soils, or a manure containing all the elements above named. To use such a manure in all cases would be a waste of material, for they are not all wanted, perhaps, in any one case. To determine what elements of manure we can most economically use, it is necessary to ascertain the condition of the soil, and the elements of nutrition required by the crop

to be raised upon it. Several of the elements of plant food, as we have seen, are volatile, and will not remaiu permanently in the soil. Others are readily soluble, and will soon be washed out of it. If they or any of them are not wanted for the immediate crop, there will be a waste of material. Could we make use, in every instance, of only those elements that are wanted to enable the soil to produce the present crop, or those that will remain permanently in the soil for the use of future crops, it is obvious that much material would be saved. Science and experience may afford us some aid, but the difficulties in the way of determining the wants of the soil and of the plants we cultivate, and of adapting our manures to these results, are so great that we must be content to submit to the loss resulting from our inability and ignorance.

THE SOURCES OF MANURE.

Carbonaceous matter, as we have seen, is derived from the natural decay or chemical decomposition of vegetables. Vegetables collected into masses, as leaves, wood, grasses, straw, the stalks and stems of all plants, fruits, grains, roots, &c., under favorable conditions of temperature and moisture, rapidly undergo, first, the fermentation; and, secondly, the putrefaction process. Where there is too much or too little heat, or too much or too little moisture, fermentation will not go on. The fibres of vegetables thus collected in masses, under favorable circumstances, soften and swell, and become permeable to air and water. Their salts, starch, gum, sugar, gluten, and extractive matter are dissolved, their carbon combines with oxygen, and carbonic acid is formed and penetrates the whole mass. This acid combines with the alkalies that are present, as potash, lime, soda, magnesia, and ammonia, and carbonates of potash, lime, &c., are formed. Certain elements in the mass soon take on the action of putrefaction. This process is owing chiefly to the presence of elements containing nitrogen, as gluten and other matters of animal origin. All animal substances pass rapidly into the process of putrefaction, and the larger the proportion of such substances mingled with the vegetable masses, the more rapidly putrefaction proceeds. Hence the addition of animal manures to vegetable composts facilitates putrefaction. By the process of putrefaction hydrogen also is rapidly developed, and combines with phosphorus and sulphur when these are present, forming sulphuretted and phosphuretted hydrogen. When the surfaces of these putrefying masses are exposed freely to the atmosphere, these gases, which are very volatile, are rapidly dissipated. To prevent this, substances should be applied which have the power of absorbing and retaining them. Carbon, when nearly pure and dry, has a strong affinity for them. The addition of dry charcoal, or of peat, will absorb large quantities of them. When these gases are thus absorbed their presence ceases to be indicated by their peculiar odors. The sulphates of lime, iron, and zinc have a similar power, hence their value as deodorizers. These sulphates have also the power of decomposing carbonate of ammonia, displacing the carbonic acid, and forming sulphate of ammonia, which is not volatile. Chloric and nitric acids will also decompose carbonate of ammonia, forming with it chlorates and nitrates of ammonia, which are soluble in water, as are also salts which they form with the other alkalies. Vegetable compost, then, when the decomposition is complete, consists chiefly of carbonaceous matter combined with gases and salts.

By a process in many respects similar to that above described, vegetable substances are decomposed in the digestive organs of animals. The fibres are comminuted by the teeth, and fitted to be pervaded and softened by the fluids contained in the stomach and intestines. A large portion of the starch, gum, sugar, gluten, and salts is dissolved out, and taken up by the lacteal vessels of the animal, and serve the purposes of nutrition, while the remainder, mixed with the juices of the animal, containing various salts, is ejected. This process is

accomplished much more rapidly than the ordinary process of vegetable decay, and the substance resulting is mixed with a large amount of animal matter, which fits it for rapid putrefaction. When the necessary conditions are present, this animal matter, which pervades the mass like leaven, sets up the process of putrefaction at once. These two processes, vegetable composting and the feeding of animals with vegetables, are the sources from which carbonaceous manures are chiefly derived. Vegetables reduced by the process of digestion, although they have parted with a large portion of their nutritive elements, yet, in consequence of the condition to which they are brought, and the additions which they have received, are more valuable as manures than when, without serving the purposes of nutrition, they are reduced by the ordinary process of decay. But the slow decomposition of vegetables is always going on in nature, and thus one generation of plants affords nutriment to those that come after it.

The carbonaceous matter resulting from the decay of vegetables is not all taken up as it is formed. Masses of it have accumulated in swamps, basins, and meadows. These accumulations, mingled with more or less of insoluble earths, constitute muck or peat, and furnish an almost unlimited amount of carbonaceous material fitted for the immediate use of the cultivator. The difference which is found in different accumulations of this material is owing in part to the difference in the vegetables from which it has been formed, and in part to the difference of the soils upon which it rests and by which it is surrounded. In some deposits the matter is almost purely carbonaceous; in some the composition is complete; in others but partial. But the most essential difference in different deposits of muck is, that some contain acids, or acids combined with minerals, while others are nearly or quite free from them. These acids are the carbonic, humic, crenic, and apocrenic. When deposits of muck are underlaid by clay, or receive the wash of clay beds in their vicinity, and iron is present, which it often is in the form of bog ore, the sulphate of alumina, which is the basis of clay, is decomposed, and the sulphuric acid combines with the iron and forms sulphuret of iron, or pyrites, which is often found in muck in sufficient quantity to impair its value as a fertilizer. When any of these acids abound in muck it is unfit to be used in a simple state. Alkalies are the proper correctives, and of these lime seems to be the best adapted to remedy the evil. Quicklime, mixed with peat, has the effect of rapidly rendering it pulverulent and light. Its influence seems to extend through the whole mass, like that of yeast through the whole mass of dough, while at the same time it combines with the acids and decomposes the salts of iron, forming salts of lime, which themselves are essential to the growth of many plants. Muck, when free or nearly free from acids, may be used by itself with great benefit on light, sandy soils, or on any soils from which the vegetable matter is exhausted; or it may be composted with stable manure, ashes, guano, or animal matters, with peculiar advantage, since it has, as we have already observed, the power of absorbing and condensing the gases arising from the putrefaction of these substances. Such composts are adapted to nearly all the uses of the garden and field.

No substance is so well adapted to composting with night soil and urine as dry muck, since it deodorizes these manures and retains all their valuable elements, and renders them manageable and easy of application, affording at the same time the dilution which is necessary for the safe application of concentrated manures. Composted with putrefying fish, muck forms an exceedingly valuable manure. The best mode of preparing muck for use is to throw it from its bed in the autumn, and leave it exposed to the action of the frosts of the succeeding winter. If it is to be composted with lime or ashes it may be used the following spring. But if it is to be composted with stable manure, night soil, or animal matters, it is better to let it remain in the heap until the. following autumn, when it should be deposited in the barn-yard or cellar, and mixed, from time to time, with the drippings of the animals. It should be