Atlanta semi-weekly journal. (Atlanta, Ga.) 1898-1920, 1917-05-04

| tncN are 3DDiiCaule 10 the average SOllS
] i'm Georgia which are normally low in
humus and organic matter. The loss
| of these substances is also greatly &C.
ceierated by our climatic conditions;
hence il is hard TO build the soil up
/ IN humus, though. of course. il is prac-
/ tiCable and desirable to do so. 1t will
/ take some years, however, to accom-
| pIish this end. and i'm the meantime
| all the results obtained indicate that
the use of rock phosphate in preference
to acid phosphate would be unsatisfac-
tory.
There is an impression among farm
ers at the present time that acid phos-
phate is so costly that they cannot af-
| ford to use it. This seems to be a
mistake as it would appear possible to
buy the available plant food at about 5
cents a pound. They are also being
misled into the belief that rock phos-
phate is much cheaper. due to the state
ments made TO them that this material
contains more phosphoric acid than
! acid phosphate. This statement is true
in only one sense of the word because
only a small proportion of the phos-
phoric acid contained in rock phosphate
will become available the first year. In
fact. ii may take several years for II
all to become available. A great deal
amount of organic matter which is as
sociated with it. On many Of our poor
er soils only a very small percentage Of
1t can be made available even under
the best systems of practice. The OBJ
ject of this article is to make this point
clear to farmers. For instance, it has
come to the writer's attention that rock
phosphate under various names is being
sold at the rate Of So a ton at the
sea board. Presumably the farmer will
expect to use several hundred pounds,
possibly 1000 pounds per acre. BY the
time the freight is paid to his local
station this material will probably cost
him s13 to $14. The chances are he
can buy acid phosphate around SIC to
SIS ton. In the material costing him
SIS to Sl4 ton only a very small per-
centage of the phosphoric acid will be-
come available to his growing crop,
whereas. the other material costing a
little more should provide his plants
with sixteen pounds of available phos-
phoric acid per 100 pounds of material
applied.
To produce a bale of cotton will call
for the presence in the soil of between
thirty and ninety pounds of available
phosphorc acid. If the farmer applies
800 pounds of high-grade material he
has placed in his soil enough of this
element to supply the needs of his cotton
crop and to exert most material infu-
encA on Fastening it's maturity. If he
puts 300 or even 500 pounds of the
other material i'm his soil he has supplied
his plants with practically 20 available
phosphorc acid. The farmer who de-
ponds on rock phosphate as general
source of phosphoric acid is quite GER
, tain to be disappointed in the results
obtained. In fact. in boil weevil terri
tory he may jeopardize his entire cot
ton crop. because it has been shown
that not only are increased yields OBJ
tanned from acid phosphate as compared
with rock phosphate. but that there is
a marked difference in the time at
which a proportionate part of the crop
will mature. Every one realizes that to
produce cotton successfully under boil
weevil conditions it is necessary to
have the bolls open in from four and a
half to five and half months from the
date of planting; hence that element,
even if somewhat more expensive, which
can be relied on to accomplish this end
is the one which should be given pref
erence under the circumstances.
Rock phosphate is obtained from
South Carolina, Florida and Tennessee.
This phosphate just as it is mined con-
tains from 90 to 40 per cent of phos-
contains twice as much phosphoric acid
as the acid phosphate of commerce, but
there is a tendency on the part of the
farmer to overlook the fact that the
phosphoric acid is available in the one
instance and not so in the other, except
through the lapse of good deal of
time or its application in association
with a large amount of organic matter,
such as few farmers possess or are in
position to secure at the present time.
Farmers should be exceedingly care
full. therefore. about buying carriers of
phosphoric acid for use on their crops
during the season of 1917. DO not be
misled by the glowing prospectus or
the specious arguments of agents with
reference to what rock phosphate will
accomplish. If in doubt, 1t is a simple
matter to write and secure definite, au-
thentic and frst-hand information. This
can be obtained from sources which
have no interests TO serve save that of
protecting the welfare Of the farmer at
a time when the cotton crop is likely to
suffer serious damage unless handled
and fortified in skillful manner. In
the presence of the boil weevil it is GER
tainly of vital importance for the farm
err TO use only those materials on his
land which will enable him to mature
part of his crop in the shortest pos
sible time.