Atlanta semi-weekly journal. (Atlanta, Ga.) 1898-1920, 1919-10-10
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GEORGIA SOILS

Comparing the plant food re
quirements of our common crops
With the average plant food con-
tent of the principal upland soils
of southwest Georgia, it will be
seen that these crops require far
lnore nitrogen than they do phos-
phoric acid or potash. Most of the
upland soils of the county have
been farmed for many years, cot
ton being the principal crop grown
on much of the land. The loose,
open character of the soil, combined
with the mild climate permits a
rapid loss of organic matter and
nitrogen. Consequently, the soils
are uniformly low in nitrogen and
under favorable conditions could
hardly furnish enough nitrogen to
produce more than one-fourth to
cne-third of a bale of cotton or II
TO II bushels of corn per acre. With
out liberal use of heterogeneous fertil-
izers, continued yields greater than
these cannot be expected unless
the nitrogen supply in the soil
is increased.
The nitrogen content of the soil
is dependent upon the content of
organic matter; from decaying vege-
to bic matter is the exclusive source
Of soil nitrogen. Clearly, then,
the first steps in soil building must
be that of greatly increasing the
present meager supply Of nitrogen
through large additions of humus
forming organic matter. 1t would be
mistake to assume that this de-
fic;ency of nitrogen could be met
solely by the use of commercial
fertilizers; for the value of fertili-
zcrs is largely dependent upon the
physical and mechanical condition of
the SOIL which in turn is influ-
enced more by the content of or
ganic matter than by any other
factor. This explains why the pro-
dLC tiveness of the soil cannot be
maintained solely by the use of
mineral fertilizers. AS the organic
matter becomes exhausted, increas-
inly larger amounts of fertilizers
must be used to N1naintain yields.
and the margin of profit becomes
smaller, until finally the fertilizer
may be used at a net loss, which
is, in fact, sometimes the case.
The methods to be followed in
maintaining and increasing the or
ganic matter and nitrogen must nee
essarily depend somewhat upon the
type of farming being practiced.
Where dairying and other live
stock farming have prominent
place, the manure from the herds
Will go a long way toward main
tanning the humus content of the
soil. But it would hardly be suffi-
Gent. 1t should be supplemented
by winter cover crops and other
Iegumlnous green manure crops,
such as cowpeas, velvet beans, etc.
These legumes will not only in
crease the humus content, but af-
ford the only economical means of
building up the nitrogen supply. In
ordinary farm practice, where cot
ton and corn are the chief crops,
these green manure crops offer the
only means of maintaining organic
matter and nitrogen. They should
be extensively grown in general
farming to prevent the soil from
becoming impoverished and unpro-
dUctive from continued cropping.
While the peanut is a legume which
is being extensively grown at
present, it is of no advantage to
the soil where the whole crop is
harvested and sold from the farm.
Do Not Burn Stalks
The practice of burning corn and
cotton stalls, and other crop residues
cannot be too strongly condemned
Referring to the table of plant
analyses, it is seen that practically
two-thirds of the plant food requir-
ed for a crop of corn or cotton re-
mains in the stalks, leaves, etc. If
these residues are burned, all the
nitrogen is lost, and the phosphoric
acid and potash remain behind in
few unevenly distributed ash heaps.
and are of little value to the sue
ceeding crop because of the uneven
over the land This
means net loss of over twelve dol
lors worth of plant food when the
stalks, leaves, etc, from a one-bale
cotton crop or hundred-bushel corn
crop are burned. Perhaps the or
ganic matter lost would have been
as valuable to the land as
the plant food contained in the re-
sidue. Approved methods of fighting
the boil Weevil call for burning all
litter or turning it under deeply. To
burn all vegetable matter off the
ground entails such a loss as would
be disastrous in it's accumulative eff
feet. Deep turning and rotation is
the best permanent practice.
The function of nitrogen is to pro-
duce growth in the plant itself, CIV
ing size of stalk and limb, and deep
green color to the foliage. It's needs
can be readily detected by weak,
stunted plants and the absence of
deep green color.
Next in importance to nitrogen and