Composting bones with ashes is a good means of securing their decomposition. They should be placed in a water-tight vessel (such as a cask); first, three or four inches of bones, then the same quantity of strong unleached wood ashes, continuing these alternate layers until the cask is full, and keeping them always wet. If they become too dry they will throw off an offensive odor, accompanied by the escape of ammonia, and consequent loss of value. In about one year, the whole mass of bones (except, perhaps, those at the top) will be softened, so that they may be easily crushed, and they are in a good condition for manuring. The ashes are, in themselves, valuable, and this compost is excellent for many crops, particularly for Indian corn. A little dilute sulphuric acid, occasionally sprinkled on the upper part of the matter in the cask, will prevent the escape of the ammonia.
What is the effect of boiling bones under pressure?
How is super-phosphate of lime made?
Describe the composition of phosphate of lime, and the chemical changes which take place in altering it to super-phosphate of lime.
Boiling bones under pressure, whereby their gelatine is dissolved away, and the inorganic matter left in an available condition, from its softness, is a very good way of rendering them useful; but, as it requires, among other things, a steam boiler, it is hardly probable that it will be largely adopted by farmers of limited means.
Any or all of these methods are good, but bones cannot be used with true economy, except by changing their inorganic matter into
SUPER-PHOSPHATE OF LIME
Super-phosphate of lime is made by treating phosphate of lime, or the ashes of bones, with sulphuric acid.
Phosphate of lime, as it exists in bones, consists of one atom of phosphoric acid and three atoms of lime. It may be represented as
By adding a proper quantity of sulphuric acid with this, it becomes super-phosphate of lime; that is, the same amount of phosphoric acid, with a smaller proportion of lime (or a super-abundance of phosphoric acid), the sulphuric acid, taking two atoms of lime away from the compound, combined with it making sulphate of lime (plaster). The changes may be thus represented.
Super-phosphate of lime may be made from whole bones, bone dust, bone-black, or from the pure ashes of bones.
How should sulphuric acid be applied to whole bones?
What is the necessity for so large an amount of water?
The process of making it from whole bones is slow and troublesome, as it requires a long time for the effect to diffuse itself through the whole mass of a large bone. When it is made in this way, the bones should be dry, and the acid should be diluted in many times its bulk of water, and should be applied to the bones (which may be placed in a suitable cask, with a spiggot at the bottom), in quantities sufficient to cover them, about once in ten days; and at the end of that time, one half of the liquid should be drawn off by the spiggot. This liquid is a solution of super-phosphate of lime, containing sulphate of lime, and may be applied to the soil in a liquid form, or through the medium of a compost heap. The object of using so much water is to prevent an incrustation of sulphate of lime on the surfaces of the bones, this must be removed by stirring the mass, which allows the next application of acid to act directly on the phosphate remaining. The amount of acid required is about 50 or 60 lbs. to each 100 lbs. of bones. The gelatine will remain after the phosphate is all dissolved, and may be composted with muck, or plowed under the soil, where it will form ammonia.
May less water be employed in making super-phosphate from bone dust or crushed bones?
Bone dust, or crushed bones, may be much more easily changed to the desired condition, as the surface exposed is much greater, and the acid can act more generally throughout the whole mass. The amount of acid required is the same as in the other case, but it may be used stronger, two or three times its bulk of water being sufficient, if the bones are finely ground or crushed—more or less water should be used according to the fineness of the bones. The time occupied will also be much less, and the result of the operation will be in better condition for manure.
Bones may be made fine enough for this operation, either by grinding, etc., or by boiling under pressure, as previously described; indeed, by whatever method bones are pulverized, they should always be treated with sulphuric acid before being applied to the soil, as this will more than double their value for immediate use.
Bone-black is chiefly used by manufacturers of super-phosphate of lime, who treat it with acid the same as has been directed above, only that they grind the black very finely before applying the acid.
What other forms of bones may be used in making super-phosphate of lime?
Why is super-phosphate of lime a better fertilizer than phosphate of lime?
What can you say of the lasting manures?
Bone ashes, or bones burned to whiteness, may be similarly treated. Indeed, in all of the forms of bones here described, the phosphate of lime remains unaltered, as it is indestructible by heat; the differences of composition are only in the admixture of organic constituents.
The reason why super-phosphate of lime is so much better than phosphate, may be easily explained. The phosphate is very slowly soluble in water, and consequently furnishes food to plants slowly. A piece of bone as large as a pea may lie in the soil for years without being all consumed; consequently, it will be years before its value is returned, and it pays no interest on its cost while lying there. The super-phosphate dissolves very rapidly and furnishes food for plants with equal facility; hence its much greater value as a manure.
It is true that the phosphate is the most lasting manure; but, once for all, let us caution farmers against considering this a virtue in mineral manures, or in organic manures either, when used on soils containing the proper absorbents of ammonia. They are lasting, only in proportion as they are lazy. Manures are worthless unless they are in condition to be immediately used. The farmer who wishes his manures to last in the soil, and to lose their use, may be justly compared with the miser, who buries his gold and silver in the ground for the satisfaction of knowing that he owns it. It is an old and a true saying that "a nimble sixpence is better than a slow shilling."
IMPROVED SUPER-PHOSPHATE OF LIME
What are the ingredients of the improved super-phosphate of lime?
To show the manner in which super-phosphate of lime is perfected, and rendered the best manure for general uses, which has yet been made, containing large quantities of phosphoric acid and a good supply of ammonia,—hereby covering the two leading deficiencies in a majority of soils, it may be well to explain the composition of the improved super-phosphate of lime invented by Prof. Mapes.
This manure consists of the following ingredients in the proportions named:—
Explain the uses of these different constituents.
What is nitrogenized phosphate?
The sulphuric acid has the before-mentioned effect on the bone-black, and fixes the ammonia of the guano by changing it to a sulphate. The twenty pounds of sulphate of ammonia added increase the amount, so as to furnish nitrogen to plants in sufficient quantities to give them energy, and induce them to take up the super-phosphate of lime in the manure more readily than would be done, were there not a sufficient supply of ammonia in the soil.
The addition of the guano, which contains all of the elements of fertility, and many of them in considerable quantities, renders the manure of a more general character, and enables it to produce very large crops of almost any kind, while it assists in fortifying the soil in what is usually its weakest point—phosphoric acid.
Prof. Mapes has more recently invented a new fertilizer called nitrogenized super-phosphate of lime, composed of the improved super-phosphate of lime and blood, dried and ground before mixture, in equal proportions. This manure, from its highly nitrogenous character, theoretically surpasses all others, and probably will be found in practice to have great value; its cost will be rather greater than guano.
We understand its manufacture will shortly be commenced by a company now forming for that purpose.
What should be learned before purchasing amendments for the soil?
What do you know of silica?
Many farmers will find it expedient to purchase bones, or bone dust, and manufacture their own super-phosphate of lime; others will prefer to purchase the prepared manure. In doing so, it should be obtained of men of known respectability, as manures are easily adulterated with worthless matters; and, as their price is so high, that such deception may occasion great loss.
We would not recommend the application of any artificial manure, without first obtaining an analysis of the soil, and knowing to a certainty that the manure is needed; still, when no analysis has been procured, it may be profitable to apply such manures as most generally produce good results—such as stable manure, night soil, the improved super-phosphate of lime; or, if this cannot be procured, guano.
NEUTRALS
SILICA
Silica (or sand) always exists in the soil in sufficient quantities for the supply of food for plants; but, as has been often stated in the preceding pages, not always in the proper condition. This subject has been so often explained to the student of this book, that it is only necessary to repeat here, that when the weakness of the straw or stalk of plants grown on any soil indicates an inability in that soil to supply the silicates required for strength, not more sand should be added, but alkalies, to combine with the sand already contained in it, and make soluble silicates which are available to roots.
Sand is often necessary to stiff clays, as a mechanical manure, to loosen their texture and render them easier of cultivation, and more favorable to the distribution of roots, and to the circulation of air and water.
CHLORINE
How may chlorine be applied?
Chlorine, a necessary constituent of plants, and often deficient in the soil (as indicated by analysis), may be applied in the form of salt (chloride of sodium), or chloride of lime. The former may be dissolved in the water used to slake lime, and the latter may, with much advantage, be sprinkled around stables and other places where fertilizing gases are escaping, and, after being saturated with ammonia, applied to the soil, thus serving a double purpose.
OXIDE OF IRON
How may the protoxide of iron be changed to peroxide?
Nearly all soils contain sufficient quantities of oxide of iron, or iron rust, so that this substance can hardly be required as a manure.
Some soils, however, contain the protoxide of iron in such quantities as to be injurious to plants,—see page 86. When this is the case, it is necessary to plow the soil thoroughly, and use such other mechanical means as shall render it open to the admission of air. The protoxide of iron will then take up more oxygen, and become the peroxide—which is not only inoffensive, but is absolutely necessary to fertility.
OXIDE OF MANGANESE
This can hardly be called an essential constituent of plants, and is never taken into consideration in manuring lands.
VARIOUS OTHER MINERAL MANURES
LEACHED ASHES
Why are leached ashes inferior to those that have not been leached?
On what do the benefits of leached ashes depend?
Can these ingredients be more cheaply obtained in another form?
Why do unleached ashes, applied in the spring, sometimes cause grain to lodge?
Among the mineral manures which have not yet been mentioned—not coming strictly under any of the preceding heads, is the one known as leached ashes.
These are not without their benefits, though worth much less than unleached ashes, which, besides the constituents of those which have been leached, contain much potash, soda, etc.
Farmers have generally overrated the value of leached ashes, because they contain small quantities of available phosphate of lime, and soluble silicates, in which most old soils are deficient. While we witness the good results ensuing from their application, we should not forget that the fertilizing ingredients of thirty bushels of these ashes may be bought in a more convenient form for ten or fifteen cents, or for less than the cost of spreading the ashes on the soil. In many parts of Long Island farmers pay as much as eight or ten cents per bushel for this manure, and thousands of loads of leached ashes are taken to this locality from the river counties of New York, and even from the State of Maine, and are sold for many times their value, producing an effect which could be as well and much more cheaply obtained by the use of small quantities of super-phosphate of lime and potash.
These ashes often contain a little charcoal (resulting from the imperfect combustion of the wood), which acts as an absorbent of ammonia.
It is sometimes observed that unleached ashes, when applied in the spring, cause grain to lodge. When this is the case, as it seldom is, it may be inferred that the potash which they contain causes so rapid a growth, that the soil is not able to supply silicates as fast as they are required by the plants, but after the first year, the potash will have united with the silica in the soil, and overcome the difficulty.
OLD MORTAR
What are the most fertilizing ingredients of old mortar?
Old mortar is a valuable manure, because it contains nitrate of potash and other compounds of nitric acid with alkalies.
These are slowly formed in the mortar by the changing of the nitrogen of the hair (in the mortar) into nitric acid, and the union of this with the small quantities of potash, or with the lime of the plaster. Nitrogen, presented in other forms, as ammonia, for instance, may be transformed into nitric acid, by uniting with the oxygen of the air, and this nitric acid combines immediately with the alkalies of the mortar.32
The lime contained in the mortar may be useful in the soil for the many purposes accomplished by other lime.
GAS HOUSE LIME
How may gas-house lime be prepared for use?
Why should it not be used fresh, from the gas house?
On what do its fertilizing properties depend?
What use may be made of its offensive odor?
The refuse lime of gas works, where it can be cheaply obtained, may be advantageously used as a manure. It consists, chiefly, of various compounds of sulphur and lime. It should be composted with earth or refuse matter, so as to expose it to the action of air. It should never be used fresh from the gas house. In a few months the sulphur will have united with the oxygen of the air, and become sulphuric acid, which unites with the lime and makes sulphate of lime (plaster), which form it must assume, before it is of much value. Having been used to purify gas made from coal, it contains a small quantity of ammonia, which adds to its value. It is considered a profitable manure in England, at the price there paid for it (forty cents a cartload), and, if of good quality, it may be worth double that sum, especially for soils deficient in plaster, or for such crops as are much benefited by plaster. Its price must, of course, be regulated somewhat by the price of lime, which constitutes a large proportion of its fertilizing parts. The offensive odor of this compound renders it a good protection against many insects.
The refuse liquor of gas works contains enough ammonia to make it a valuable manure.
SOAPERS' LEY AND BLEACHERS' LEY
What use may be made of the refuse ley of soap-makers and bleachers?
What peculiar qualities does soapers' ley possess?
The refuse ley of soap factories and bleaching establishments contains greater or less quantities of soluble silicates and alkalies (especially soda and potash), and is a good addition to the tank of the compost heap, or it may be used directly as a liquid application to the soil. The soapers' ley, especially, will be found a good manure for lands on which grain lodges.
Much of the benefit of this manure arises from the soluble silicates it contains, while its nitrogenous matter,33 obtained from those parts of the fatty matters which cannot be converted into soap, and consequently remains in this solution, forms a valuable addition. Heaps of soil saturated with this liquid in autumn, and subjected to the freezings of winter, form an admirable manure for spring use. Mr. Crane, near Newark (N. J.), has long used a mixture of spent ley and stable manure, applied in the fall to trenches plowed in the soil, and has been most successful in obtaining large crops.
IRRIGATION
On what does the benefit arising from irrigation chiefly depend?
What kind of water is best for irrigation?
How do under-drains increase the benefits of irrigation?
Irrigation does not come strictly under the head of inorganic manures, as it often supplies ammonia to the soil. Its chief value, however, in most cases, must depend on the amount of mineral matter which it furnishes.
The word "irrigation" means simply watering. In many districts water is in various ways made to overflow the land, and is removed when necessary for the purposes of cultivation. All river and spring water contains some impurities, many of which are beneficial to vegetation. These are derived from the earth over, or through which, the water has passed, and ammonia absorbed from the atmosphere. When water is made to cover the earth, especially if its rapid motion be arrested, much of this fertilizing matter settles, and is deposited on the soil. The water which sinks into the soil carries its impurities to be retained for the uses of plants. When, by the aid of under-drains, or in open soils, the water passes through the soil, its impurities are arrested, and become available in vegetable growth. It is, of course, impossible to say exactly what kind of mineral matter is supplied by water, as that depends on the kind of rock or soil from which the impurities are derived; but, whatever it may be, it is generally soluble and ready for immediate use by plants.
What is the difference between water which only runs over the surface of the earth, and that which runs out of the earth?
Why should strong currents of water not be allowed to traverse the soil?
Water which has run over the surface of the earth contains both ammonia and mineral matter, while that which has arisen out of the earth, contains usually only mineral matter. The direct use of the water of irrigation as a solvent for the mineral ingredients of the soil, is one of its main benefits.
To describe the many modes of irrigation would be too long a task for our limited space. It may be applied in any way in which it is possible to cover the land with water, at stated times. Care is necessary, however, that it do not wash more fertilizing matter from the soil than it deposits on it, as would often be the case, if a strong current of water were run over it. Brooks may be dammed up, and thus made to cover a large quantity of land. In such a case the rapid current would be destroyed, and the fertilizing matter would settle; but, if the course of the brook were turned, so that it would run in a current over any part of the soil, it might carry away more than it deposited, and thus prove injurious. Small streams turned on to land, from the washing of roads, or from elevated springs, are good means of irrigation, and produce increased fertility, except where the soil is of such a character as to prevent the water from passing away, in which case it should be under-drained.
Irrigation was one of the oldest means of fertility ever used by man, and still continues in great favor wherever its effects have been witnessed.
MIXING SOILS
How are soils improved by mixing?
The mixing of soils is often all that is necessary to render them fertile, and to improve their mechanical condition. For instance, soils deficient in potash, or any other constituent, may have that deficiency supplied, by mixing with them soil containing this constituent in excess.
It is very frequently the case, that such means of improvement are easily availed of. While these chemical effects are being produced, there may be an equal improvement in the mechanical character of the soil. Thus stiff clay soils are rendered lighter, and more easily workable, by an admixture of sand, while light blowy sands are compacted, and made more retentive of manure, by a dressing of clay or of muck.
Why may the same effect sometimes be produced by deep plowing?
What is absolutely necessary to economical manuring?
Of course, this cannot be depended on as a sure means of chemical improvement, unless the soils are previously analyzed, so as to know their requirements; but, in a majority of cases, the soil will be benefited, by mixing with it soil of a different character. It is not always necessary to go to other locations to procure the soil to be applied, as the subsoil is often very different from the surface soil, and simple deep plowing will suffice, in such cases, to produce the required admixture, by bringing up the earth from below to mingle it with that of a different character at the surface.
In the foregoing remarks on the subject of mineral manures, the writer has endeavored to point out such a course as would produce the "greatest good to the greatest number," and, consequently, has neglected much which might discourage the farmer with the idea, that the whole system of scientific agriculture is too expensive for his adoption. Still, while he has confined his remarks to the more simple improvements on the present system of management, he would say, briefly, that no manuring can be strictly economical that is not based on an analysis of the soil, and a knowledge of the best means of overcoming the deficiencies indicated, together with the most scrupulous care of every ounce of evaporating or soluble manure.