68 
AMERICAN AGRICULTURIST. 
[March, 
Scientific and Practical Talks about 
Manures—III. 
( Continued, from page 40.) 
Let us clearly understand the leading points of 
the two previous chapters. We have assumed : 
(a)—That nearly all the food of all kinds of 
plants, is derived from the air; the food floats 
about in a form so transparent, or in particles so 
minute, as not to be seen by the eye. ( b )—That 
while some of this plant food is absorbed through 
the leaves, other portions are taken in through 
the roots—a part being washed down to the roots 
oy rains, and a part being carried there by the air 
which circulates in the porous surface soil, (c) — 
That to increase the growth of plants, we add to 
the ordinary food, extra supplies in the form of 
manures, (d) —That owing to the constant 
change of air, it is impracticable to increase the 
supply of food around the leaves, in open field 
culture, and therefore food can only be supplied 
through the roots, by means of manures placed 
in the soil around the roots, (c) —That all plants, 
of whatever kind, are chiefly composed of four 
elementary substances, viz: Oxygen, Hydrogen, 
Nitrogen , Carbon *—there being, besides these, a 
small amount of mineral matter, which is left in 
the form of ashes when the plants are burned. 
Sometimes, also, a little sulphur, or other matter, 
is found in plants, hut not enough to be taken into 
account here. ( f )—It was assumed in the first 
place, that Oxygen and Hydrogen, being the ele¬ 
ments of water, are probably supplied insufficient 
abundance for all the wants of plants, by the 
moisture in the air and in the soil; second, that 
carbon (charcoal) which is so abundant in all 
plants, is probably furnished in abundance by the 
carbonic acid always found in the air to which 
it is supplied in abundance by the decaying of 
plants It was suggested that perhaps additional 
useful supplies of carbon may be yielded by the 
decaying of plants in, or on the soil. 
Three of the four chief elements of the plant, 
being thus provided for, we now come (g) to dis¬ 
cuss the fourth and last organic element in 
plant food, viz. : nitrogen. This is, probably, 
the most important one to be considered. 
As previously stated, air is made up of about 
21 parts (by weight) of oxygen and 79 
parts of nitrogen. But nitrogen itself is not 
freely absorbed by water, and hence the supply 
of this element carried to the roots of plants, is 
not large. Further, there are reasons for be¬ 
lieving that nitrogen is not directly appropria¬ 
ted by plants, in its simple state. Nitrogen, how¬ 
ever, combines with hydrogen under favorable 
circumstances, and forms a substance called 
ammonia, familiarly known as “ spirits of harts¬ 
* After printing a few thousand copies of the first edi¬ 
tion of our February number, which was hastily sent to 
press, the manure article, on page 40, was re-written more 
carefully, some new matter being added, and the final 
paragraph omitted. The following explanatory note was 
also added, and being important we repeat it here.- 
Carbon, an element entering largely into all living sub- 
tanc.es, whether animal or vegetable, is seen in its nearly 
•ure state in common charcoal— Oxygen, an element con- 
. tituting fully half of the entire substance of the globe, 
mineral as well as organic, is never seen in its pure, un¬ 
combined state, for in this state it is a transparent gas, 
like air. It enters into combination with other substances, 
but is still invisible, just as lime is invisible when 
combined in moriar.— Hydrogen, which forms one-ninth 
part of water, and enters largely into many organic sub¬ 
stances, is also an invisible gas, when not combined with 
some other element. — NiTnooEN, which forms seventy- 
nine hundredths of common air, and also enters into 
many organic substances, is likewise an invisible gas when 
in its pure Mate.—A mmonia, is a compound of 14 parts by 
weight of nitrogen united with 3 parts of Hydrogen. (Am¬ 
monia is familiar to (post persons under the name of 
f! jlprtshorp 
horn.'’ (See the last explanation in previous 
note.) This compound, (ammonia) is very solu¬ 
ble in water, but it is somewhat rare, and, with¬ 
out some special source of supply, the water 
around the roots may be comparatively deficient 
in nitrogen, or ammonia. This we conceive to 
be a reason why ammoniacal or nitrogenous 
manures (those containing nitrogen or some of 
its compounds), are found to be so beneficial to 
plants. 
Let the preceding statements be fully compre¬ 
hended, viz.: that of the four organic elements 
making up the bulk of all plants, oxygen and hy¬ 
drogen are abundant everywhere—in vapor 
in the air, and in the moisture of the soil; that 
carbon is also somewhat abundant in the atmos¬ 
phere and in the soil; but that nitrogen, in an 
available form, is not abundant, and therefore its 
addition to the soil is likely to be more beneficial 
than any one of the other three elements named. 
With this view of the subject, our first question 
in regard to any proposed fertilizer would be : 
How much available nitrogen, or ammonia, does it 
contain ? 
PRACTICAL ILLUSTRATIONS AND DEDUCTIONS. 
1st. The above theory is strongly confirmed by 
the experience of all observing cultivators. 
Weight for weight, pure Peruvian guano has 
proved to be one of the most powerful fertilizers ; 
and this material, when of best quality, contains 
about one-sixth part of its weight of ammonia, 
or about one-seventh of its weight is nitrogen. 
2d. Unburned bones contain much nitrogen, in 
a form to be readily transformed into ammonia, 
when they decay; and in our own practice we 
have found unburned bones, ground very fine so 
as to decay quickly, to be one of the best and 
cheapest manures for all kinds of crops. We 
should speak oftener and more strongly in regard 
to the value of bone saw-dust, or powdered 
bones, but from the fact that the supply is so 
limited that only few persons can obtain it in 
quantity. Though bones contain less ammonia 
in a tun than guano, they are sold at a lower 
price, and have the advantage of being harmless 
when put directly in contact with seed or growing 
plants, which is not always the case with guano. 
3d. Blood, night-soil, sheep’s dung, poultry 
droppings, and horse manure, are among the best 
fertilizers, and these yield much ammonia. Every 
one knows how strong is the smell of hartshorn, 
(ammonia) when horse-manure is fermenting or 
decaying. It should always be composted 
(mixed) with plenty of straw, or muck, or even 
with earth, to catch and hold its ammonia, and 
not allow it to escape into the air and be lost. 
4th. Urine, (the liquid droppings of all ani¬ 
mals,) contains much nitrogen. It can scarcely 
stand in a warm place for six hours, without a 
strong smell of hartshorn, (escaping ammonia.) 
Urine is so rich in ammonia, that not a pint of it 
should lie wasted from either the stables or 
privies. Almost all the nitrogen in the excre¬ 
ments of a milking cow, is found in the urine, 
while the solid droppings contain but little. Hence 
the well known low value of cow manure, while 
the urine is so valuable to plants. In some of 
the most highly cultivated parts of Belgium, the 
urine of a single cow sells for $10 a year. 
5th. The straw of wheat, rye, barley, oats, 
and corn, and others of a woody character, 
are organic materials, but they are chiefly 
composed of oxygen, hydrogen, and carbon, and 
contain little nitrogen. As every one knows, 
they make comparatively poor manures, though 
they are often valuable to loosen the soil. They 
yield a little ammonia, however; and perhaps their 
carbon is of some value, as stated above. 
« 
6th. Pea straw, clover, and some of the grasses, 
on the contrary, contain a considerable percent¬ 
age of nitrogen. Experience teaches that a crop 
of clover, for example, when turned under, is one 
of i he best fertilizers. 
7th Fats and oils are chiefly composed of 
carbon, hydrogen, and oxygen, being almost de¬ 
void of nitrogen. Who ever heard of pure oil, or 
fat, being useful as a manure 1 
9th. Lean flesh, on the contrary, contains 
much nitrogen, and this is certainly a very valu¬ 
able fertilizer. Take a dead horse or ox, remove 
the fat, or not, and compost the rest of the ani¬ 
mal with a mass of muck or earth, and the ma¬ 
nure obtained will highly enrich from ten to fifty 
square rods of ground, the amount depending 
upon its previous good or bad condition, and the 
size and the amount of flesh of the animal. 
And so we could go on with other illustrations, 
which, like the above, indicate that the relative 
amount of nitrogen in each of the articles is a fair 
criterion forjudging of their comparative value as 
fertilizers. And here we will say, that, just what 
our theory would indicate in regard to the rel¬ 
ative value of these articles as fertilizers, is 
in almost every case in accordance with what 
has been the result in practice. 
Caution .—Many of the makers and venders 
of artificial fertilizers now publish analyses of 
their compounds. If this were always done 
fairly,^he analysis would assist in estimating 
the value of the fertilizer. But, we are sorry 
to say, this is seldom the case. One mode of de¬ 
ception is, to get a true analysis of an extra 
good specimen, or selection, and publish this as 
a fair sample of the article sold in market. An¬ 
other plan is, to employ some unscrupulous 
chemist, who has, by fair means or foul, obtained 
a notoriety, and whose analyses are guessed out 
in accordance with the wishes of his employer. 
A third and very common deception is, to give 
the analysis somewhat in detail, but instead of 
stating just how much ammonia or nitrogen it 
contains, we have figures shovving a large per¬ 
centage of “ organic matter, yielding ammonia.'' 
This is nonsense, or worse! A substance may 
contain ten to fifty per cent of “ organic 
matter, yielding ammonia,” and yet not contain 
half a per cent of ammonia. We advise to 
ignore every fertilizer which is put forth 
with this specious deception. For ourselves, we 
would not purchase any manure, which we 
did not know to contain the elements of 2 to 
2£ per cent, of ammonia, for every ten dollars 
of its price per tup. 
There are certain fertilizers offered to the 
public, such as phosphatic guanos, and others, 
the proprietors of which ignore the value of am¬ 
monia, and base their claims upon the (supposed) 
value of the phosphoric acid. These we shall 
refer to in another article, when discussing the 
mineral constituents of plants, to which so much 
value has been attached. 
Our limits preclude the discussion here of the 
mode of using manures. We will just add briefly 
now, that, as manures nTe designed to be absorb¬ 
ed by the roots of plants, it is important that 
they bo finely divided or pulverized, and be inti¬ 
mately mixed with the soil. No single root of a 
plant, or small mass of roots, can do the feeding 
for all the others. The manure must be mingled 
through the soil,'so as to be accessible to all the 
roots. 
It may sound like a paradox, yet the breaking 
of both wings of an army is a pretty sure way to 
make it fly. 
He is poor whose expenses exceed his income 
