Port Tobacco times, and Charles County advertiser. (Port Tobacco, Md.) 1845-1898, 1848-11-02
AGRICULTURAL L.
THE LAW OF MANURES,

mures ascend or descend ~ has lately been
considerably discussed. For our own part,
we should no more think of asking or dis
cusing such a question than we should
whether moisture ascends or descends p
1t obviously does both s.; and SO it is with
manures, unless the term manures is to be
restricted 10 mineral substances only.
But thong h we believe that the valuable
parts OF manures may be both carried into
the air and washed into the earth, we do not
admit the Propriety of some positions, by
which the fact is attempted to be illustrated
For instance, 1t is said 'the gases of ma
nure ascend, but the salts descend" The
fact is here lost sight Of, lha, the same sub
stances, of assuming both gaseous and SOL
III form. Such Is the case with carborn,-
which constitutes the greatest part of ordi-
nary manures, as we'll as vegetable snbs,an-
ces; and also with nitrogen, (which has
formerly been held by chemist, and is, in
deed, still held by many chemists,) as the
most valuable and Important element in
msnures.
IL a heap of manure is left to ferment on
she earth, or without! being covered by some
absorbing substance, its bulk and wei ht are
greatly reduced. What has become of The
lost portion II has, Of course, gone into
ahe air, as it would have done if the manure
had been acted on by fire, the manure, or
certain portion of il, has been resolved into
its original elements, and the carbon and
nitrogen it contained have again become
parts of the atmosphere.
The nitrogen in manure is ia the form of
ammonia, and that it escapes during fermen-
ta'ion, has been proved; it is perceptible by
the smell, and has, also, by means of acids,
been detected in its ascent Most people
are familiar with ammonia in the form of
salt, and know that in this form it is extreme
ly volatile, and readily passes into an ariform
state. 1t is also easily soluble in wafer ::
and is, therefore, readily washed into the
earth by rains. Thus the very substance
which forms salt, may become gas and as
cend into the air; or it may become IL
quid and descend into the earrh
Nlanures may be combined with substan-
ces which wilipreven.ahee escape of ammonia;
such as charcoal, charcoal-dust from coal
pits, peat, muck, soil, and vegetable or car
bonaceous subs.ancesgeneralIy. 1.-THE pro-
cess of fermentation is properly regulated,
and the manure is combined with articles
which will absorb the gases as they are dis
engaged, there will be no waste. 1t may be
considered rule, that, that whenever smell
is emitted by manures, some Of their valua-
BILE properties are being dissipated hence
aheir odors should not be wasted Ton the
desert air;'' they should be saved and con-
verted into vegetable substances, in which
condiuon they are not only more agreeable
10 the eJfactories, but become substantial
elements of animal nutrition.
As to the sinking of manures, there is
positive evidence of the fact. We have in
many instances seen its effects to the depth
of several feet. On the farm of Mr.. Prem
iice near this city, it was lately noticed, in dig
ging cellar near where a compost heap
had laid, that the earth, to the depth of three
feet from the surface, though it was of quite
a compact and clayey nature, was so i'm
pregnated with the qualities of manure that
.hey were plainly percepible. And the ei-
dects of manure are always traceable to
greater of less depth, in proportion to the
porousness of the soil and the quantity of
manure applied. 1t lis LIEBIG's opinion tina,
the soluble pats of manures, "phospha,es
and other salts with alkaline bases," are
drawn of, and wasted 10 a great extent by
percolation.
The depth to which manure should be 6u-
1ied IS another subject, which, in connexon
with the question, whether they rise or fall.
has been much discussed and some, who
believe that manures ascend, have arrived at
the conclusion that they should be placed
from "a foot 10 eighteen inches'' under
ground.
We 10 no. suppose it is practicable to lay
down any fixed rule in regard to the cover
ing of manures. Some general principles,
however, may form guide. 1t is evident
that manures can only afford nu,riment to
plants when they are in soluble condition.
In their application, therefore, the causes
which produce solution and decomposition
should be regarded. These causes are, prin-
cipally, heat, air and moisture; thoug h in
the elimination and assimilation of food by
plants, light and electricity are evidently
powerful agents. Most of these principles
act with the greatest force near The surface.
In some cases, as in dressing grass-lands
we would spread manures on the top of the
ground. But in such cases, we would use
well-ro''ed compost, in which The animal
manures had been combined with such sub
stances as would absorb the matters that
during fermentation ght pass of: The
reason why we would prefer, for such
purpose, manure that had passed through
the first stages of decomposition in the man
ner mentioned, is. that it would be more
readily soluble, than in fresher stale, and
would be Immediately available to the crop;
while at the same time its facilitating prin-
ciples would be so far combined and fixed.