St. Landry democrat. (Opelousas, La.) 1878-1894, 1886-09-04
COMPOSITION OF SOILS.
A Study Which Every Intelligent Land
Owner Should Pursue.

owner Should Pursue.
There is no more important study for
the farmer than a careful study of his
soil. While soils are composed OF three
distinct onstituents-sand, clay and
humus-yet these vary greatly in their
composition. ALI soils, as far as their
inorganic materials are concerned, were
originally composed by the breaking
down and decomposition of rock.
Sands result from the decomposition of
quartz, or other rock containing quartz
or silica in some form,san the compost
ton of each individual grain is that of
the rock from which it was formed.
Soils formed of granite are among the
most productive known. Why? Gran
lite is composed of quartz, feldspar and
mica. The quartz is pure slick, so
necessary for the proper division OF
soils. Feldspar again consists of silica,
alumina and potash. Alumina is the
base of clay, just as the metal aluminium
is the base Of alumina, alumina being
an oxide of aluminium, and is the char
acteristic ingredient in all clays. With
out it soils could not be combined and
held together. With too much alnmina
it becomes 100 dense, hard and impervi
Gus both to water and the roots of
plants.
Humus is any organic matter in pro-
cess of decay or in that state when re-
duced to an impalpable powder. Prai-
RE soils contain great deal OF humus
that seems to have been deposited when
the soil was under water or partially so.
So the fact that these soils. as a rule,
are largely composed of clay, are due
their fertility and lasting qualities, the
dark color of the soil being due to
humus, and also to the effects of burn
ing of the vegetation year after year.
Soils are generally classed as sandy,
loamy, clayey, mucky and peaty, the
latter being formed in marshy land I'M
der water. Our very black prairie soils
containing much clay and vegetable
matter, are often designated muck. A
distinctly clay soil is that composed of
pure clay. Pure sand has no fertility,
pure clay can not be classed as fertile,
and peaty soils are not fertile until they
have long been unearthed by careful,
thorough drainage.
Mixtures of sand and clay are our
most fertile soils. They are classified
as lean when they contain equal vol
nmes of sand and clay, as sandy loan
when about seventy-tive per cent. is
sand, and as clay loan when about
seventy-fve per cent. is clay. AS soils
approach either of these conditions they
are classed with that to which they re:
late most closely. !:
The province of humus in the soil is
two-fold; to render the soil light and
mellow, though its principal value is
the power that humus possesses of de-
composing and rendering soluble the
valuable constituents of the soil. es-
pecially those of potash with nitrogen.
Humus is formed by the action of the
air on solid animal or vegetable matter.
In fact, it is 4 process OF exceedingly
slow combustion, as much as five hum
dred years being considered necessary
to reduce a large oak to humus in the
natural progress of decay. During all |
this time, however, such portions as
are gradually converted into humus are
performing their natural functions in |
the soil. One of the most important is
the conservation of nitrogen-the most
costly, as it is the most easily dispelled |
of the organic products. Under the
action of heat and moisture n trogen
combines with the potash of the soil,
nitrate of potassa, the common
name of which is saltpeter.
From the foregoing the farmer may
by careful observation estimate the
value and character of his soil, and
hence the proper crops to be used, and
also the manures necessary to increase
a sandy soil may be
rendered productive by the addition of
clay. Ten per cent of clay will con-
vert it into a sandy loan. But pure
,lay can not be rendered productive by
he addition of sand. 1t would require
1t least twenty-five per cent. of sand to
convert it into a stiff clay loan. Pure
lay freed from uncom tined silica con-
lists of alumina 44.5, silica 40 and
water 1915 parts in 100. But except in
are cases it is not found. except COM
lined more or less, with free silica, or
and - HIio00o Tt.jb9fy7o