Atlanta tri-weekly journal. [volume] (Atlanta, Ga.) 1920-19??, 1922-12-09
Maintaining and Increasing the Fer
tility of Southeast Georgia Soils


This article constitutes the second
paper dealing with the manner of
maintaining and increasing the fer
tility of the soils of southeast Geor-
g1a. In it is described also the part
phosphoric acid, potash, lime and
rotation of crops must be made to
play in this very essential and fun
damental undertaking. Read and
study it in association with the first
article dealing with this topic, which
appeared in recent issue.
Phosphoric Acid: Next in impor
lance to nitrogen and organic mat
ter is the need of an increased sup
ply of phosphoric acid. There is a
wide difference, however, in the con-
tent of phosphoric acid in the diff
ferent soils. The need of available
phosphoric acid has been generally
recognized in the use of fertilizers
relatively high in this element, but
the practice does not generally take
into account the different soil types
on which the fertilizer is to- be
used. The availability of the phos-
phoric acid is largely dependent up
on the content of organic matter
and the general physical condition Of
the soil, so that even a high content
of this element may be of little val
ue when the land is allowed to get
in rundown condition from con-
tlnued clean cultivation.
In fertilizers used directly under
crops to meet immediate needs.
phosphoric acid should be applied in
the form of acid phosphate or other
available form. However, in u
scheme of permanent agriculture,
where soil building is an object, rock
phosphate affords the cheapest
source of phosphorus. Phosphoric
acid can be bought in this form for
about 12 cents per pound, where
as it costs several times as much
in the form of acid phosphate. How
ever, the soil must be well stocked
with humus in order to get good re-
suits from rock phosphate; for it
is only in the presence of decaying
organic matter that this material
will give up its phosphorus. In con-
ncctlon with green manures or with
heavy applications of farm manure,
rock phosphat should give good re-
suits. 1t should be applied broad
cast at the rate of 1000 to 1000
pounds per acre about every five
years. This should be supplemented
with small amounts of acid phcs
phate. if needed, but the amount Of
the expensive form required will be
greatly reduced and a net saving
made. 1t is well to remember, how
ever. that rock phosphate, of what
ever brand or source, cannot take
the place of acid phosphate as a
source of available phosphoric acit
in mixed fertilizers or for any 9th
er purpose where an immediatelv
available material is desired.
Phosphoric acid performs A spe
cial function in the fruiting of
plants, and hastens maturity. Thus,
it is particularly important under
cotton when the boil weevil is pres
ent.
Poor fruitage and late maturity
are indications of a need of phos
phorus.
Potash; The soils of Pierce co,lr-
While the potash content is several
times that of either nitrogen or
phosphoric acid, only a fraction of
per cent of the total potash in
the soil will become available for
the use of crops each year under
best conditions, and where the soils
are poor in organic matter, the
chemical changes that potash min.
erals must undergo to become avail
able are further retarded. For these
reasons potash becomes a limiting
factor in crop production, especial
ly where several crops have been
grown with little or no potash ap.
piled in the fertilizer With the
restoration of normal prices, fer
tilizers carrying a liberal amount of