Year: 1875

1t would seem to be surprising that crops
should ever fail for want of such insigni6-
cant quantities of these elements as here
enumerated, and which are so minute when
compared with tue whole bulk OF the soil as
to be almost beyond the reach of the chem
list. But, although the chemist may be able
to discover comparatively largo quantities of
these substances in the soil, yet they may
not exist, and very rarely do exist, in con-
dtion in which they can be appropriated by
plants. To be of use as food for plants,
they must be soluble in water. If the whole
OF these substances existing in the soil were
soluble, they would be carried off in a few
years in the rain-water which passes through
the upper soil into the subsoil and thence
into springs, rivers, and finally the ocean.
Fortunately, therefore, for us they exist in
an insoluble state, and it is only by the ex-
ercise of human industry, the cultivating
aud manuring the soil, that they are render
ed soluble and available. In this fact lies
the whole essence of the theory and practice
Of agriculture. What We call a virgin soil
such one as we find in a newly cleared
forest or upon a newly.broken prairie-is a
soil in the best condition for agriculture
Its valuable mineral elements have been
slowly brought into q soluble condition by
the gradual decomposition Of leaves, roots,
grass, and various other vegetable matters
which fill the place Of the manures from the
barn-yard, and are ready to be taken up by
crops. The farmer who settles upon these
new lands raises his crops without difficulty,
and in profusion, for few years. BY and
by the crops grow less and less, and the
lands are said to be exhausted really, they
are only exhausted in the sense in which a
laborer who has not eaten for twelve hours
is exhausted. No more labor can be got out
of him until he is rested and refreshed by
food. All his strength then returns II
the man works on he faints and is unable to
make any effort. So if the land is still
worked it yields nothing. But lot the farm.
er feed it with small portion Of manure, in
itself containing less than one crop demandG
from the soil, and a succession of crops may
be again taken. Or if a quantity Of lime
be added in caustic condition, although
the soil may contain a large proportion Of
carbonate of lime, then the soil is frequently
restored to a condition of fertility immedi.
atsy, and retains it for several years. Oh
if the soil receives what is known as SUN.
mer fallOw-that is several plowings aud
harrowiugs during season without bearing
any crop, and Is exposed to the suns heat
to moisture, aud to tho influence of the at
mosphere,. again, in some measure, greater
or less, its fertility is improved. 1t can b,
only in this case that portion of the miner
al substances have been rendered soluble by
these powerful agencies. In the previous
cases the addition of the manure or the lime
has had the same effect.


1t soils were not thus exhausted there
would be no agriculture. Mankind would
be able to live without labor, except such al
should be necessary to gather the fruits and
grains which would grow spontaneously, and
civilization would not exist. 1t would be
curious to speculate on what would be our
condition were ii not for this fact, which we
are apt to look upon as the foundation aud
cause of our greatest adversely, VIZ that
without labor and toll the earth shall yield
no fruit, and that it is only by the sweat Of
the brow that man shall eat bread.