The Madisonian. (Richmond, Ky.) 1913-1914, 1913-11-18

(By Geo. Roberts, Agronomist Kentuc
Within the last few years raw
ground phosphate rock has come into
use, more or less extensively, in some
sections of the country in the improve
ment of soils deficient in phosphorus.
Formerly it was thought to be useless
as a material for direct application to
the soil. 1t was thought that the only
means for making it available was
to convert it into acid phosphate or
superphosphate by treating it with
sulfuric acid. This belief arose from
the fact that farmers generally applied
it in small quantities, perhaps in the
hill, on soils that had become unpfo-
ductive and deficient in organic mat
ter. Under such conditions, little or
no results were obtained the first year,
and its use was discontinued and the
material was pronounced worthless.
Acid phosphate used in similar man
ner under similar conditions generally
gives more or less profitable returns
the first year. Hence there has grown
up the practice of small annual appli-
cations of acid phosphate or the so
called complete fertilizers" of which
acid phosphate is the chief constituent
"a practice that does not, as rule,
take into account the permanent fer
tility Of the soil.
In recent years, however, expert
ments have been conducted at num-
Der of Experiment Stations, notably
Illinois and Ohio, which show that the
use of raw phosphate rock under prop
er conditions is as profitable as the
use of acid phosphate.
Raw phosphate should be used in
rather large applications, in connec-
ton with organic matter, either N the
form of manure, crop residues or
green manure crops. A reasonable ap-
plication is 1000 to 1000 pounds per
acre once in a rotation Of three or
four years, the practice to be kept up
until the soil is supplied with fair
content of phosphorus. If the crops
are fed and the manure is carefully
saved and returned to the soil, when
applications amounting to three tons
per acre have been made to the aver
age farming lands outside the blue
grass region, they will contain a fairly
good supply of phosphorus.
Raw phosphate rock can generally
be bought delivered at most places in
Kentucky for IS to So per ton. The
above applications will be found no
more expensive than the use of small
amounts of complete fertilizers and if
used in good crop rotations which pro-
vide organic matter and contain le-
gumes sufficient to keep up the nitro
gen supply. will give more profitable
results
A good practice is to apply the raw
phosphate in connection with manure.
1t may be sprinkled in the stable as
the manure accumulates, using about
a pint per day per animal; or 1t may
be put on the manure as 1t is being
hauled out, a layer of manure being
put down in the wagon or spreader,
then the proper amount of raw phos.
phate in turn. With this method, it is
much better to use the manure spread.
er in order to get an even distribution.
Another satisfactory method is to
apply the material broadcast to be
plowed in with a sod or green manure
crop. The standard practice with the
Kentucky Experiment Station is to ap-
ply the material on the sod which is to
be turned for corn. However done,
the application should be made on the
nnplowed ground and thoroughly disk
cd in and then plowed under The
thorough distribution of the material
is a very important consideration.
The Kentucky Experiment Station
has compared acid phosphate and rock
: phosphate on an extremely worn red
clay limestone soil near Burnside, KY
for the past FIVE years. Potash salts
we're used with both forms in orde,