The Iuka vidette. (Iuka, Miss.) 1894-1912, 1910-01-20
Uses and Value of Commercial Ferti-
lizers

lizers.
The matter of fertilizers for Missis-
sippi farmers is an especially important
one. The United States Department of
Agriculture has recently re-issued lit
tie bulletin on fertilizers, written by DIR.
Knapp, that is especially interesting and
instructive. 1t is given herewith for the
benefit of those who read this publca-
ton:
Since the prime object in the use of
all commercial fertilizers is to increase
production, they must be used either to
supply plant rood directly or to so act
upon the soil that larger quantity of
its nutritive elements will be at the dis
posal of the plant. In actual practice,
most commercial fertilizers combine both
effects. All the substances required by
plants except three-nitrogen, phos-
phoric acid and potash--are abundant in
most soils.
'The chief function of nitrogen in
plants is to promote growth, but it is
also of very great Importance in the
perfection of fruit. Nitrogen enters
largely into the composition of plants,
and it follows that everything of vegeta-
BILE origin is valuable source of this
substance. When vegetable matter is
burned, the nitrogen is released from its
combination and escapes into the atmos-
phere and is lost. ut is a bad practice
to burn off fields and destroy vegetable
matter; it is better to turn it under
The humus in vegetable matter has
value in soil renovation frequently great
err than its value as a plant food) The
forms most important to the farmer of
the South in which nitrogen is available
are vegetable matter, the droppings of
animals, cotton seed meal, bone meal
nitrate of soda, sulphate of ammonia,
and the products of the slaughter pen
in what is known as tankage.
Next in Importance as a plant food
is phosphoric acid. 1t is largely required
by the plant for growth, but is abso-
lutely essential in the perfection of seed,
and is greater factor in fastening the
maturity of crops. The form of phos-
phoric acid most accessible to the farm
er is known as acid phosphate.
Potash is more directly effective in
promoting fruitage, but it is rarely very
deficient in soils, and especially in soils
of the gulf states 1t is found in alum
dance in ashes. Commercially, it is
most cheaply obtained in the form of
kainit.
What Fertilizer to Buy.
"Since the elements of plant food al
ready mentioned are required in differ
ent quantities by different plants, and
since the soils vary in their supply, it is
well for the farmer to know what his
soil and plants need before investing
his money in fertilizers. The practical
way for the farmer to determine these
facts is to observe the growth of the
plants on his land. If the plants grow
rapidly and make an abundance of leaf
and stalk, it is evidence of a good sup
ply of nitrogen. If there is not an ap-
proportionate amount of fruit, it is a
sure indication that the soil needs phos-
phoric acid. On the other hand, if the
plant has not good color and tends to
drop its fruit before it reaches a fair
size, it indicates that the soil requires
potash.
"Most of the soils of the South are
deficient in both nitrogen and phosphoric
acid and some in potash. So when we
buy commercial fertilizers we buy them
for their content of these substances.
If the farmer has saved all his manures
and has grown COW peas abundantly, as
he should, he will rarely have to buy
nitrogen.
How to Buy Fertilizer.
Commercial plant food, called fer
tilizer,' is never sold pure, but in COM
bination with other substances. The
substances with which it is combined
are of no value to the farmer, but sim
ply add to the weight. The laws of
nearly all of the states now require that
on each sack of commercial fertilizer
shall be stamped just what plant food it
contains. This composition is given in
percentages, which means that in hum
dred pounds of the fertilizer there are so
many pounds of the particular sub
stances. For example, a certain fertilizer
is offered for sale, on the sack of which
is branded the following:
Nitrogen ............... 8 per cent.
Soluble phosphoric acid.... 6per cent.
Reverted phosphoric acid.... 4per cent.
Available phosphoric acid. 10 per cent.
Potash 2per cent.
"Transplanted into terms of pounds,
this means that in a sack weighing 100
pounds there are
'Three pounds of nitrogen.
ask pounds of soluble phosphoric acid.
"Four pounds of reverted phosphoric
acid.
"Ten pounds of available phosphoric
acid.
"Two pounds of potash.
'rhis gives a total of is pounds OF
plant food in 100-pound sack. When
ton of such fertilizer is bought, the
purchaser secures nitrogen, 60 pounds
soluble phosphoric acid, 100 pounds; re-
verted phosphoric acid, so pounds; and
potash, 40 pounds. Notice that what Is
called available is the sumlo Of the solu'
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