MINOR ARTIFICIAL MANURES.
In addition to the manures which have been discussed in previous
chapters, there are a number of minor manures which are used to a very
much smaller extent--dried blood, hoofs, horns, &c.
Among these one of the most valuable is dried blood. Fresh blood,
containing 80 per cent of water, has from 2.5 to 3 per cent of nitrogen,
about .25 per cent of phosphoric acid, and about .5 per cent of
alkalies. When dried it forms a very concentrated and valuable
nitrogenous manure, which has long been used in France. The commercial
article contains, on an average, about 12 per cent of nitrogen, and
slightly over 1 per cent of phosphoric acid. When mixed with the soil it
ferments, and the nitrogen it contains is converted into ammonia.
Although not so quick-acting a manure as nitrate of soda or sulphate of
ammonia, it can by no means be described, as is done in ordinary
agricultural text-books, as a slow-acting manure. Its nitrogen may be
regarded as of equal value to that in Peruvian guano. It is peculiarly
suited for horticulture, and is chiefly used in this country as a manure
for hops. It has also been used with beneficial results for wheat,
grass, and turnips. As a manure it is best suited for sandy or loamy
soils. Considerable quantities are exported to the sugar-growing
colonies as a manure for sugar-cane. Manures are made from other animal
refuse. It may be mentioned that lean flesh (containing 75 per cent of
water) has about 3 to 4 per cent of nitrogen,.5 per cent of alkalies,
and .5 per cent of phosphoric acid; that is to say, a ton of lean flesh
would contain about 70 lb. of nitrogen and 10 lb. of phosphoric acid. In
air-dried flesh, according to Payen and Boussingault (containing 8-1/2
per cent of moisture), there is 13 per cent of nitrogen. Flesh,
therefore, is, when properly composted, a valuable nitrogenous manure.
Dried flesh is generally made into a manure called meat-meal guano, the
composition of which we have already referred to in the chapter on
Guano.[240]
Hoofs, horns, hair, bristles, and wool, wool-waste and the intestines of
animals, have been used as manures. Hoofs and horns form a regular
source of artificial nitrogenous manure; the latter being obtained as a
bye-product in the manufacture of combs and other articles. They are in
the form of a fine powder; and in order to increase their rate of
action, which is very slow, they are often composted in America with
horse-manure before use. They have also been composted with slaked lime.
There can be no doubt that such treatment increases very considerably
their value. Their percentage of nitrogen seems to vary very much
according to the kind of animal from which they are derived. In nine
samples of horn the nitrogen was found to vary from 7-1/2 to 14-1/4 per
cent; giving an average of 11-1/3 per cent. The nitrogen seems rarely to
exceed 15 per cent. The amount of phosphoric acid they contain has been
found by various investigators to range from 6 to 10 per cent. S. W.
Johnson found only from .08 to .15 per cent in buffalo-horn shavings. In
France what is known as "torrefied" horn has been used. This is horn
which has been subjected to the action of steam. The nitrogen in this
material is considered to be more active than in ordinary horn.
According to Way, horns have been used for the hop crop with good
results. Ground hoof is very similar in composition to horn, and
contains about 14 to 15 per cent of nitrogen. Considerable quantities
are now used. It must be remembered, however, that horns, hoofs, hair,
bristles, &c., although rich in nitrogen, possess a comparatively low
manurial value. The home production of these articles may be estimated
at 6000 to 7000 tons.
_Scutch._
Scutch is the name given to a manure made from the waste products
incidental to the manufacture of glue and the dressing of skins. It
contains about 7 per cent of nitrogen, and is manufactured in London to
the extent of several thousand tons annually.
_Shoddy and Wool-waste._
Shoddy, which is a manure made from waste-wool products, is a material
largely manufactured in this country, and which was formerly (it is now
used to a considerably less extent) used to a large extent as a manure.
Its annual production amounts to about 12,000 tons. There are three
qualities,--the first containing 8 to 12 per cent of nitrogen; the
second, 6 to 8 per cent; and the third, 5 to 8 per cent. Shoddy is by no
means a very valuable manure. Woollen-waste products were formerly much
richer in nitrogen than is now the case. This is due to the fact of the
adulteration with cotton, now so prevalent in the manufacture of woollen
goods. Pure woollen rags should contain 17 to 18 per cent of nitrogen.
It has been strongly recommended to treat woollen waste with caustic
alkali before being used as a manure, in order to render their nitrogen
more quickly available; and there is a good deal to recommend this
treatment. When wool-waste is applied as a manure, it should in every
case be in autumn, so as to allow as long a period as possible to elapse
before it is required for the plant's growth.
Leather has also been used as a manure. Its nitrogen may be stated at
from 4 to 6 per cent; and it may safely be described as of all materials
used as nitrogenous manures the least valuable. Leather is, from its
very nature, admirably adapted to resist decomposition when applied to
the soil, and unless it is reduced to a very fine condition, might be
trusted to remain undecomposed for a long period. Torrefied leather,
however, is probably of greater value. It is obtained in the same way as
torrefied horn, already referred to--namely, by treatment with steam.
The grease and fatty matters which so largely aid it in resisting
decomposition being extracted, it is much better suited for manurial
purposes than ordinary leather. Torrefied leather contains from 5 to 8
per cent of nitrogen.
_Soot._
A manure which has long been used and highly esteemed is soot. Obtained
in the usual way, it generally contains some 3 per cent of nitrogen,
chiefly in the form of sulphate of ammonia, and small quantities of
potash and phosphates. A varying proportion of the nitrogen is present
in the form of ammonia salts; and this undoubtedly confers upon soot its
manurial value. It has long been used as a top-dressing for young grain
and grass, and has been applied at the rate of from 40 to 60 bushels per
acre. It has an indirect value as a slug-destroyer.
Many of the above-mentioned manures, of comparatively low value, will
probably be less used in the future than they have been in the past,
owing to the more abundant supplies of nitrate of soda and ammonia salts
which are now available. Many of these substances have probably been
used in mixed manures.
FOOTNOTES:
[240] See p. 324.