If the decomposition of animal bodies takes place in exposed situations, and without proper precautions, the ammonia escapes into the atmosphere, and much of the mineral portion is leached out by rains. The use of absorbents, such as charcoal-dust, prepared muck, etc., will entirely prevent evaporation, and will in a great measure serve as a protection against leaching.

If a dead horse be cut in pieces and mixed with ten loads of muck, the whole ma.s.s will, in a single season, become a most valuable compost.

Small animals, such as dogs, cats, etc., may be with advantage buried by the roots of grape-vines or trees.

BONES.

[Of what do the bones of animals consist?

What is gelatine?

Describe the fertilizing qualities of fish.]

The _bones_ of animals contain phosphate of lime and gelatine. The gelatine is a nitrogenous substance, and produces ammonia on its decomposition. This subject will be spoken of more fully under the head of 'phosphate of lime' in the chapter on mineral manures, as the treatment of bones is more directly with reference to the fertilizing value of their inorganic matter.

FISH.

In many localities near the sea-sh.o.r.e large quant.i.ties of fish are caught and applied to the soil. These make excellent manure. They contain much nitrogen, which renders them strongly ammoniacal on decomposition. Their bones consist of phosphate and carbonate of lime; and, being naturally soft, they decompose in the soil with great facility, and become available to plants. The scales of fish contain valuable quant.i.ties of nitrogen, phosphate of lime, etc., all of which are highly useful.

Refuse fishy matters from markets and from the house are well worth saving. These and fish caught for manure may be made into compost with prepared muck, etc.; and, as they putrefy rapidly, they soon become ready for use. They may be added to the compost of stable manure with great advantage.

[Should these be applied as a top dressing to the soil?

What are the fertilizing properties of woollen rags?

What is the best way to use them?]

Fish (like all other nitrogenous manures) should never be applied as a top dressing, unless previously mixed with a good absorbent of ammonia, but should when used alone be immediately plowed under to considerable depth, to prevent the evaporation--and consequent loss--of their fertilizing gases.

WOOLLEN RAGS, ETC.

_Woollen rags, hair, waste of woollen factories_, etc., contain both nitrogen and phosphate of lime; and, like all other matters containing these ingredients, are excellent manures, but must be used in such a way as to prevent the escape of their fertilizing gases. They decompose slowly, and are therefore considered a _lasting_ manure. Like all _lasting_ manures, however, they are _slow_ in their effects, and the most advantageous way to use them is to compost them with stable manure, or with some other rapidly fermenting substance, which will hasten their decomposition and render them sooner available.

Rags, hair, etc., thus treated, will in a short time be reduced to such a condition that they may be immediately used by plants instead of lying in the soil to be slowly taken up. It is better in all cases to have manures act _quickly_ and give an immediate return for their cost, than to lie for a long time in the soil before their influence is felt.

[What is their value compared with that of farm-yard manure?

How should old leather be treated?

Describe the manurial properties of tanners' refuse.

How should they be treated?

Are horn piths, etc. valuable?]

A pound of woollen rags is worth, as a manure, twice as much as is paid for good linen shreds for paper making; still, while the latter are always preserved, the former are thrown away, although considered by good judges to be worth forty times as much as barn-yard manure.

Old leather should not be thrown away. It decomposes very slowly, and consequently is of but a little value; but, if put at the roots of young trees, it will in time produce appreciable effects.

_Tanners' and curriers' refuse_, and all other animal offal, including that of the slaughter-house, is well worth attention, as it contains more or less of those two most important ingredients of manures, nitrogen and phosphate of lime.

It is unnecessary to add that, in common with all other animal manures, these substances must be either composted, or immediately plowed under the soil. Horn piths, and horn shavings, if decomposed in compost, with substances which ferment rapidly, make very good manure, and are worth fully the price charged for them.

ORGANIC MANURES OF VEGETABLE ORIGIN.

_Muck_, the most important of the purely vegetable manures, has been already sufficiently described. It should be particularly borne in mind that, when first taken from the swamp it is often _sour_, or _cold_, but that if exposed for a long time to the air, or if well treated with lime, unleached ashes, the lime and salt mixture, or any other alkali, its acids will be _neutralized_ (or overcome), and it becomes a good application to any soil, except peat or other soils already containing large quant.i.ties of organic matter. In applying muck to the soil (as has been before stated), it should be made a vehicle for carrying ammoniacal manures.

SPENT TAN BARK.

[Why is decomposed bark more fertilizing than that of decayed wood?]

_Spent tan bark_, if previously decomposed by the use of the lime and salt mixture, or potash, answers all the purposes of prepared muck, but is more difficult of decomposition.

[How may bark be decomposed?

Why should tan bark be composted with an alkali?

Why is it good for mulching?

Is sawdust of any value?]

The bark of trees contains a larger proportion of inorganic matter than the wood, and much of this, on the decomposition of the bark, becomes available as manure. The chemical effect on the bark, of using it in the tanning of leather, is such as to render it difficult to be rotted by the ordinary means, but, by the use of the lime and salt mixture it may be reduced to the finest condition, and becomes a most excellent manure. It probably contains small quant.i.ties of nitrogen (obtained from the leather), which adds to its value. Unless tan bark be composted with lime, or some other alkali, it may produce injurious effects from the _tannic acid_ which it is liable to contain. Alkaline substances will neutralize this acid, and prevent it from being injurious.

One great benefit resulting from the use of spent tan bark, is due to its power of absorbing moisture from the atmosphere. For this reason it is very valuable for _mulching_[AD] young trees and plants when first set out.

SAWDUST.

[Why is sawdust a good addition to the pig-stye?

What is the peculiarity of sawdust from the beech, etc.?

What is a peculiarity of soot?

Why may soot be used as a top dressing without losing its ammonia?]

_Sawdust_ in its natural state is of very little value to the land, but when decomposed, as may be done by the same method as was described for tan bark, it is of some importance, as it contains a large quant.i.ty of carbon. Its ash, too, which becomes available, contains soluble inorganic matter, and in this way it acts as a direct manure. So far as concerns the value of the ash, however, the bark is superior to sawdust.

Sawdust may be partially rotted by mixing it with strong manure (as hog manure), while it acts as a _divisor_, and prevents the too rapid action of this when applied to the soil. Some kinds of sawdust, such as that from beech wood, form acetic acid on their decomposition, and these should be treated with, at least, a sufficient quant.i.ty of lime to correct the acid.

_Soot_ is a good manure. It contains much carbon, and has, thus far, all of the beneficial effects of charcoal dust. The sulphur, which is one of its const.i.tuents, not only serves as food for plants, but, from its odor, is a good protection against some insects. By throwing a handful of soot on a melon vine, or young cabbage plant, it will keep away many insects.

Soot contains some ammonia, and as this is in the form of a _sulphate_, it is not volatile, and consequently does not evaporate when the soot is applied as a top dressing, which is the almost universal custom.