The Marietta journal. [volume] (Marietta, Ga.) 1866-1909, 1902-06-19
C acid, lime and nitrogen.

&c aclQ, lime ana nitrogen
Potash and pbosphoric acid are
usually contained in soils in small
quantity, varying from about one-tentI
of pound in a hundred pounds OF
the soil to one pound in one hundred
pounds. Although that amount looks
small; let us figure it by the acre.
Weight of the Soil Per Acre.
An average soil. when dry, if taken
to the depth of nine inches, will
weigh three to three and one-half mil
lion pounds to the acre. Therefore a
soil containing one-tenth of one per
cent of phosphoric acid, would really
contain three thousand to thirty-five
hundred pounds of phosphoric acid pei
acre, or as much as could be obtained
by the application of ten to twelve tons
OF high-grade acid phosphate per acre.
You would at once then say that soil
containing one-tenth per cent of pot.
ash or phosphoric acid ought to be a
rich soil and should not require any
fertilizers, but there you would be
wrong, because it matters not so much
what is the total amount of potash
or phosphoric acid In an acre of soil
as 1t does to know in what condition
that phosphoric acid or potash exists.
Availability of the P!ant-Food in the
Soil.
The question arises, is it soluble,
is it available? 1t is in such condition
that the soil water can take it up and
convey it to the roots and root hairs
OF the plant, ready for absorption by
them into the characterization? That
is why we find it necessary to put
acid phosphate and kainit and other
fertilizers on lands which are being
constantly cropped; it is because the
constant cropping has exhausted or
drawn out of the soil the soluble phos.
phoric acid and potash, available to
the plant, and we must either put on
fertilizer containing them in a soljt.
bic form, or we must let the soil rest
while, that is ''lic fallow," in order
that fresh supply Of plant food may
be made available ny the slow action
i OF the soil water, he action of car.
bonic acid, and the ether organic acids
resulting from the decay Of vegetable
and animal matters in the soil. II
! you cannot afford to either put on fer.
tilizer or to let YOU" land "lie fallow.'
| then your next res 5urce is to rotate
your crop; that is, % plant on the soil
which has begun to fail you some
other crop of difr rent nature, which
may not require 50 much of certain
element of plant tood as the previous
crop did. For instance, follow cotton
| with peas or clover.
What Determines he Crop-Produc.:. /
Power the Soil.
In considering tie capacity of a soil
| to produce crops we must remem.
Der one thing, and that is that the es.
| senttal element which exists in the
smallest amount settles the custom of
tn crop-producing powr of soil. That
Is to say, if soil is vry rich in avail.
| able phosphoric acid, nitrogen, lime,
magnesia, and the other essential ash
4 "h0 JOI NC pun III
potash, that soil cannot produce heavy
| crops without the application of an
available potash fertilizer. If that soil
has only available potash enough in
1t to produce ten bushels of corn per
acre, or two hundred pounds of seed
cotton per acre, then all you are going
to get out of that soil is ten bushels
OF corn, or two hundred pounds OF
seed cotton, no matter whether there
was available phosphoric acid and nj.
trogen and lime, etc, in the soil
enough to produce forty bushels of
corn or fifteen hundred pounds of seed
cotton. This brings us to the question
OF soil analysis, which we will treat in
| our next letter.
JOHN NJ. McCANDLESS.