The Savannah morning news. (Savannah, Ga.) 1900-current, 1903-01-19
WAISTS of Plant Food in Soil.

waists of Plant Food in Soil.
All titled soils are subject to a con-
slant waste of the plant food ele-
ments; that is, Nitrogen, potash and
phosphoric acid, says the Mirror and
Farmer. Soils contain. as a natura
condition, all three of these necessary
substances, which. by disintegration
form the great bulk of our soils. and
the nitrogen, in the form of vegeta BILE
matter, the residue Of plant growth
a pure soil, of course, contains nc
vegetable matter, but furnishes a me-
dunn for the growth of plants of the
clover family, which has the power
when supplied with potash and phos-
phoric acid, of assimilating the inert
nitrogen of the atmosphere. The de-
cay Of the roots, etc, of this class OF
plants supplies nitrogen for the growth
of plants which cannot make their
own nitrogen, so to speak, and thus
step by STEP we have the agricultural
soil of to-day.
Plant food must be soluble in soil
waters before plants can make use of
1t to accelerate growth, and it is in
this great point the greatest losses oc-
cur. For example, if more plant food
is made soluble than the plants in that
immediate spot can assimilate, the
quantity not taken up passes on with
the drainage water, to be taken UP
more or less by the feeding roots of
plants it meets in passing on to the
streams and water courses. More or
less fails to be utilized in this purpose
and ultimately finds it's way to the
ocean, where it serves to grow ma
rine plants. Nitrogen is subject to
losses in addition to this. BY the ac-
ton of certain bacteria the nitrogen
in decaying vegetable matter is con-
verified into ammonia, which may es-
cape in the air as a gas, or this am
monia, by the action of other micro
organisms, may be changed back into
the inert form of nitrogen as found in
the atmosphere, and which is useless
as plant food.
great deal may be done to lessen
these losses, though they can never be
wholly prevented. The heaviest losses
occur In the fall, winter and early
spring, when the surface evaporation
of water is light, and the drainage in
to water courses consequently heavy,
Under these conditions the soluble
plant food, made so by the seasons
tillage, is freely washed into the
drainage channels. BY keeping the
soil covered with catch crops much
of this loss may be prevented but ii
crop. For this purpose, rye, scarlet
clover, cowpeas and field peas are
used and should be used whenever pos
sible. Fall blowing is excellent in inn
proving the physical condition of the
SOIL but the plant food thus liberated
is woefulIy wasted by the spring rains
This wastage is a condition which we
have to consider as a practical fact
One of the important matters in con-
nection with same to take into consid-
Grafton is the probable disturbance OF
the plant food balance by such losses
Nitrogen we may disregard, as we can
win that back by the growth of le-
gumes-clover, cowpeas, etc. Potash
and phosphoric acid present a differ
ent problem. Potash Is subject to Sc
we're losses, as when it is soluble in
water there are few combinations
which render it again insoluble. Phos-
phoric acid, on the other hand is very
apt to take insoluble forms, and the
loss of this plant food by the solution
of phosphoric acid at once fixes il
against loss. ALL these points must
be considered in figuring on any
scheme to maintain the fertility of the
soil by applying manures or fertiliz-
erS.