| As
you already know, most
arable soils contain the necessary plant food elements to a
considerable
extent, but only in a very limited degree in available forms.
They
are actualy locked up in the soil larder, and only after undergoing
physical
and chemical changes
may be taken up by the feeding roots of plants. They are unlocked only
by the disintegration and decomposition of the soil particles, under
the
influence of cultivation--or mechanical breaking up--and the access of
water, air and heat.
The
soil is naturally classified
in two ways: first, as to the amount of plant food contained; second,
as
to its mechanical condition--the relative proportions of sand,
decomposed
stone and clay, of which it is made up, and also the degree to which it
has been broken up by cultivation.
The
approximate amount of
available plant food already contained in the soil can be determined
satisfactorily
only by experiment. However, almost all soils without exception need
liberal
manuring to produce good garden crops.
To
learn more about soil variations read: The
3 Basic
Variations
Of Soils
The
ideal garden soil is
what is known as a "rich, sandy loam," at least eight inches deep; if
it
is deep eighteen it will be even better. It contains the proper
proportions
of both sand and clay, and further has been put into the best of
mechanical
condition by good tilth.
That
last word brings us
to a new and very important matter. "In good tilth" is a condition of
the
soil difficult to describe, but a state that the gardener comes soon to
recognize.
Ground,
continually and properly
cultivated, comes soon to a degree of fineness and lightness at once
recognizable.
Rain is immediately absorbed by it, and does not stand upon the
surface;
it does not readily clog or pack down; it is crumbly and easily worked;
and until your garden is brought to this condition you cannot attain
the
greatest success from your efforts.
We
emphasized "properly cultivated."
That means that the soil must be kept well supplied with humus, or
decomposed
vegetable matter, either by the application of sufficient quantities of
organic manures, or by green manuring, or by "resting under grass,"
which
produces a similar result from the amount of roots and stubble with
which
the soil is filled when the sod is broken up.
Only
by supply of good quality
humus your garden will have the chance to be kept in that light,
friable,
spongy condition which is absolutely essential to luxuriant vegetable
growth.
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