The Elements of Agriculture Part 26

What is the reason of the superiority of bone dust?

How is bone-black made?

Of what does it consist?]

Bones are applied to the soil in almost every conceivable form. _Whole bones_ are often used in very large quant.i.ties; their action, however, is extremely slow, and it is never advisable to use bones in this form.

Ten bushels of bones, finely ground, will produce larger results, during the current ten years after application, than would ensue from the use of one hundred bushels merely broken, not because the dust contains more fertilizing matter than the whole bones, but because that which it does contain is in a much more available condition. It ferments readily, and produces ammonia, while the ashy parts are exposed to the action of roots.

[Should farmers burn bones before using them?

How would you compost bones with ashes?

In what way would you prevent the escape of ammonia?]

_Bone-black._ If bones are burned in retorts, or otherwise protected from the atmosphere, their organic matter will all be driven off, except the carbon, which not being supplied with oxygen cannot escape. In this form bones are called _ivory black_, or _bone-black_. It consists of the inorganic matter, and the carbon of the bones. The nitrogen having been expelled it can make no ammonia, and thus far the original value of bones is reduced by burning; that is, one ton of bones contains more fertilizing matter before, than after burning; but one ton of bone black is more valuable than one ton of raw bones, as the carbon is retained in a good form to act as an absorbent in the soil, while the whole may be crushed or ground much more easily than before being burned. This means of pulverizing bones is adopted by manufacturers, who replace the ammonia in the form of guano, or otherwise; but it is not to be recommended for the use of farmers, who should not lose the ammonia, forming a part of bones, more than that of other manure.

_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 quant.i.ty 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 ma.s.s 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

{ Lime Phosphoric acid { Lime { Lime

By adding a proper quant.i.ty 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.

{Phosphoric acid} Super-phosphate Phosphate of lime {Lime } of lime.

{Lime} {Lime} Sulphate of lime.

Sulphuric acid}

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 ma.s.s 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 quant.i.ties 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 ma.s.s, 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 ma.s.s. 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 const.i.tuents.

_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 s.h.i.+lling."

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 quant.i.ties 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:--

100 lbs. bone-black (phosphate of lime and carbon).

56 " sulphuric acid.

36 " guano.

20 " sulphate of ammonia.

[Explain the uses of these different const.i.tuents.

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 quant.i.ties 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 quant.i.ties, renders the manure of a more general character, and enables it to produce very large crops of almost any kind, while it a.s.sists 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 surpa.s.ses 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.