The following is a summary of the experi mental statement of Mr. J. B. Lawes on the effect of different fertilizers on oats grown on the same land during the three years from 1869 to 1871, inclusive, at Rothamsted, England: The previous croppings were 1847 and 1848, cloVer dressed with different manures; 1849 to 1859, beans with different manures; 1860, fallow; 1861 and 1862, wheat, unmanured ; 1863, fallow ; 1864, beans, dunged, 1865, wheat, unrnanured ; 1866, beans, numanured; 1867 and 1868, wheat, unma nured. The area of the experiment was three quarters of an acre, which was divided into six plots. As to applications per acre, plot one was not manured; plot two received 200 pounds sulphate of potash, 100 pounds sulphate of soda, 100 pounds sulphate of magnesia, and three and one-half cwt. superposphate of lime made from 200 pounds bone-ash, 150 pounds sulphuric acid of 1.7 specific gravity, and water; plot three received 400 pounds ammonia salts, composed of sulphate and muriate .of ammonia of commerce in equal parts; plot four received 400 pounds ammonia salts, 200 pounds sulphate of potash, 100 pounds sulphate of soda, 100 pounds sulphate of mag nesia, three and one-half cwt. superphosphate; plot five received 550 pounds nitrate of soda, (containing the same amount of nitrogen as 400 pounds ammonia salts ;) plot six received 550 pounds nitrate- of soda, 200 pounds sulphate of potash, 100 pounds sulphate of soda, 100 pounds sulphate of magnesia, three and one-half cwt. superphosphate. The table page 629 gives results.
The following is an abstract of a report of pri vate experiments made in Scotland: The soil was a good clay loarn of very even quality, in very moderate agricultural condition, the subsoil a light sandy loam. The field was divided into sixteen plots of one-eighth of an acre each. Fur rows were laid out twenty-seven inches apart, the manures were placed in the bottorn of these furrows, and potatoes of the regent variety were dropped thereon, ten inches apart, May 1, 1871; the potatoes were then covered by running the plow through the ridge made between the fur rows and throwing back the earth, according to the current practice of the region. The after cultivation consisted of laand and horse hoeing, and finally earthing up. The potatoes were dug artificial manure alone. The table shows the manures applied and the results obtained per acre, and given substantially in the order of largest yield, as it occurred. The left hand col umn indicates the relative locality of each plot. The sulphate of ammonia contained twenty-four per cent. of ammonia; the dissolved coprolites, twenty-six per cent. of soluble and five per cent. of insoluble phosphate; and the kainit, or potash salt, twenty-four per cent. of sulphate of potash. As to the sources of manure it is stated as fol lows: Carbonaceous matter 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, etc., under November 2; were sorted over a one and five eighths inch riddle and the large and small were separately weighed and pitted. At this time no diseased tubers were observed. On the 15th of March they were taken from the pits, the dis eased tubers thrown out and the sound ones weighed. The diseased tubers amounted to about one-third of the whole crop, the propor tion not varying greatly between the different plots, but being sornewhat greater in the plots which received dung than in those which received favorable conditions of temperature and moist ure, 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 fibers 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, etc., are formed. Cdrtain 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 man tres to vegetable composts facilitates putrefac tion. By the process of putrefaction hydrogen also is rapidly developed, and combines with phosphorus and sulphur when these are present, forming sulphuretted and phosphoretted hydro gen. 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 indi cated 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 aud 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 com post, 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, vege table substances are decomposed in the digestive organs of animals. The fibers 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 ani.mal, and serve the purposes of nutrition, while the re mainder, mixed with the juices of the animal, con taining various salts, is ejected. This process is accomplished much more rapidly than the ordi nary process of vegetable decay, and the substance resulting is mixed with a large amount of animal matter, whieh 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 compost
ing and the feeding of animals with vegetables, are the sources frotn which carbonaceous man ures 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 pur poses of nutrition, they 0,re 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 accumu lations, mingled with more or less of insoluble earths constitute muck or peat, and furnish an almost unlimited amount of carbonaceous mate rial 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 compo, sition is complete; in others but partial. But the most essential difference in different deposits of muck is, that some contain acids, or acids com bined with minerals, while others are nearly or quite free from them. These acids are the car bonic, humic, crenic, and apocrenic. When. deposits of muck are underlaid by clay, or reeeive 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 decoinposed, 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 fertil izer. 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, fonning 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 malter 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 putrefac tion of these substances. Such composts are adapted to nearly all the uses of the garden and field No substance is so well adapted to com posting with night soil and urine as dry muck, since it deodorizes these manures and retains all their valuable elements, and renders them man ageable and easy of application, affording at the same time tbe dilution which is necessary for the safe application of concentrated manures. Com posted 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 is evident that it should be provided in sufficient quantity to be used freely as a deodorizer about the premises whenever or wherever it may he wanted. It will thus become charged with gases and salts, and be converted into a highly valuable manure, which for a garden and for fruit culture has perhaps no. equal. Many skillful farmers consider a com post of one-half good muck and one-half stable manure fully equal for corn culture to pure stable manure. Vegetable composts, animal excrements, and muck are then the chief sources -of carbonaceous manures. With these, as we have seen are combined various gases and salts which are essential to vegetable growth, either as elements of nutrition or as stimulants. These may also be found in more concentrated forms and in smaller bulk, capable of more easy and direct application to growing plants. Variously combined and condensed, these fertilizing ele ments constitute the numerous articles known in commerce as artificial manures. All plants (luring their growth take from the soil more or less mineral matters. Some require them in large quantities. Such plants are said to -exhaust the soil on which they gro w. The srnall grains, which appropriate in their culms and seeds much silex, lirne, and potash, are instances of this class. The elements of which we are now speaking are all soluble, and are -vvashed out of the soil—and the better the soil is worked and the finer the tilth, the more rapidly does this take place—and, unless they are fre quently rene wed, the cultivated soil is soon -exhausted of them. Owing to their small bulk they are easily applied. Nitrogenous manures are Peruvian g-uano, night-soil, poudrette, urine, hair, wool-waste, fish manures, and animal sub stances generally. The phosphates are bone meal, superphosphate of lime, and Mexican guano. All these are combined with mineral earths and alkalies, and it is to these that is due whatever permanent value such manures possess, the other elements being so soluble and volatile that their effects are immediate and temporary. In this connection we may mention the saltpe fres or nitrates, a class of manures to which little attention has been paid in this country. Earth containing nitrate of potash is often found in caverns, where it has been accumu lating for ages, protected from the weather. Large quantities of it are imported from Chili. The nitrates may be manufactured artificially by means of nitre beds. These are formed hy meam; of earth and animal manures mixed with potash, lime, and soda. They are protected from the rain by roof's open on all sides to the air. The inixture is kept at the proper degree of moisture, and frequently Stirred to expose new surfaces to the atmosphere. Nitrates of lime, potash, and soda are formed, and the whole mass becomes impregnated with them.