Atlanta tri-weekly journal. [volume] (Atlanta, Ga.) 1920-19??, 1921-04-19
AGRICULTURAL EDUCATION
az DR.. ANDREW M. SOULE

I before quoting a price since they
can usually make better price on a
| large amount than on a small guam
| tity, and the price may be cheaper
| for one time of delivery than for an
other. Therefore, in asking quota
tionS, unless you have a good com
mercial rating with the established
agencies. enclose letter of reference
form some individual or firm that
has such rating and state spec1ficaI-
ly what is wanted giving the exact
tonnage of each material, time of
shipment, whether delivered prices
are required. and destination of car.
Many farmers know what formula
they wish to use from a study OF
, the effects of different formulas on
their land from year to year. For
the benefit of any who may be I'M
decided, the following romulas, which
were indicated from the results of
experiments with cotton, are given.
Since the amount of nitrogen in the
soils of any class will vary according
as the supply has been maintained
and built up, the amount of nitrogen
to be applied in fertilizer should be
different as the conditions require.
For northwest Georgia. 1920 to a
1880. (the three figures In the
formula denote the percentages of
phosphoric acid. ammonia and potash,
respectively. in the mixture). The
application of potassium does not
pay in this section. For the red clay
lands of the Piedmont, a 1920 to
1882. (only small application of
potassium will pay). For the sandy
lands of the Piedmont. a 1922 to a
1888, potassium is needed and will
pay). For the red clay lands of the
costal plain, $50 to a 9-3-2 (only
a small application of potassium will
Nf
gen to phosphorus is needed in the
costal plain than in other parts Of
the state). and for other soils of the
costal plain. a 9-2-3 to a 9-3-5.
In selecting materials to make up
the fertilizer. the farmer will fire.
quently desire to use cottonseed or
cottonseed meal or other materials
that he may have, for all or part of
the heterogeneous material. Phosphorlc
and potash materials must be pur-
chased. Care should be taken not
to mix materials that will cause a
loss of plant food or a lumpy mix
ture.
To know the amounts of materials
needed in a fertilizer of any certain
formula, we must know the amount
of each element of plant food for
which the formula calls. In 1888
there would be ten per cent OF 2,UOO
pounds, or 200 pounds of phosphorlc
acid. three per cent of 1000 pounds,
or so pounds of ammonia, and three
per cent of 1000 pounds, or 60 pounds
of potash. Knowing the pounds Of
each element plant food needed and
the per cent of plant food in the
different materials, we can determine
the amounts of materials required.
In the commercial mixing of fer
tilizer. where materials are used that
contain a high proportion of plant
food, it is sometimes necessary to
add material that contains no plant
food to keep the percentage OF plant
food in a ton of the mixed fertilizer
from being higher than is called for
by the formula.
Inasmuch as material that contains
no plant food is of very little value
in a fertilizer. it is recommended that
instead of the addition of so much
material, such as sand, as a filler,
the application of the mixture be
made at a lesser rate per acre. For
example, if it is desired to apply 400
pounds per acre of a 1888 and 1900
pounds of your mixture contains the
same amount of plant food that 1000
pounds of the commercial 1898 con-
tains, apply 1,S00-2,000 or nine-tenths
(0.9) as much of your mixture or at
the rate of $50 pounds per acre.
In some cases it may be desirable
to use as materials more of the bulky
farm products than are used COM
mercially, which will result in more
than ton of mixture to contain the
same amount of plant food contain
ed in a ton of the commercial mix