The citizen. [volume] (Berea, Ky.) 1899-1958, 1914-04-02
PHOSPHORUS As A FERTILIZER

The following is prize thesis
by I. n. Chestnut prepared for Prof
Clark's class in study Of soils:
OF the three most essential ele-
ments in soil fertility, viz, nitro
gen, phosphorus and potassium;
the one most likely to be deficient
in the average soil, is phosphorus
There are several reasons for
this. O. most soils seem to con-
tain naturally less Of this element
than Of the other two above nam
ed, more especially potassium, ~
Large amounts Of phosphorus are
removed from the farm, never Ia
return, being sold in the grain or
seed Of corn, wheat and oats; and
in the bones Of animals, (3) On
most soils there is an abundance
Of potassium, especially in the sub
soil, and nitrogen is easily added
by manure and leguminous plants
but the limited supply Of phos-
phorus is drawn upon from year
10 year, and practically none is
ever returned, except the small
amount added in ordinary complete
fertilizer aud farm manure which is
far short Of the amount lost annual
~. az On many farms (where the
land is rolling or hilly) large guam
titles Of phosphorus may be lost by
erosion, and sCme is lost by leach.
ing
Thus we see the importance OF
considering carefully the subject OF
phosphorus in relation TO the fer
tility Of the soil.
Pure phosphorus is an elemen-
tary, non-mctallic substance OF a
waxy nature. II is semi-transpar-
ent, luminous, poisonous and highly
combustible, ant is absolutely es-
sentiai to the growth and structure
OF every plant and animal. How
ever. VI is not fodnd in the soil in its
pure form. but is in combination
with other elements usually lime
when IL is known as phosphate OF
lime" The term "phosphoric acid
is often used by chemists TO desig-
nate the amount Of phosphorus
found in the combination, especially
where sulfuric acid has been used Ia
render the raw form Of fertilizers
more available.
The amount Of phosphorus found
in different soils varies widely from
200 TO 200 lbs. per acre, TO as many
thousand, but IL must be remem-
bered that only about or per cent
Of il becomes available for the use
Of plants annually. A 80 bu. crop OF
corn will remove about % lbs. OF
phosphorus from the soil. 80 bu. oil
oats, about IL lbs, % bu. of wheat
about ~ lbs. So we see that grain
farming especially viii soon eN
haust the supply Of phosphorus in
our soils.
DIR. Cyril G. Hopkins Of the Illinois
Experiment Station. one of the
highest authorities in this country
states that the amount of phos-
phorus taken from the soil of ILL
nois by the average corn crop i,
such that IL would completely ex-
haust $4,000 acres of this best corr
belt land and that 10 return IL would
require all the manure from The
leading 5O0.00O,O00 bushels of corn
or the application Of 20,000,000 dol
lars worth Of ordinary complete fer
lizer while the economical method
of using raw phosphate would cost
2,O00,0O0."
This is better understood perhaps
, when we remember that three
fourths Of the phosphorus con-
tanned IN grain crops, corn, wheat
and oats is found in the grain oI
seeds and when these crops are fec
to animals on the farm one fourth
Of the phosphorus is retained il
the bone and flesh of the animal.
Thus We see there must be a con-
tinual loss of this element, which i:
much less however where some
form of stock raising is practical, SC
that all crops grown can be con-
sumed at home, thus retaining Q
large part of all the elements in the
manure. But even then there is Q
loss Of phosphorus which must be
supplied by the purchase of some
form OF PHOSPHORUS in order 10
keep up the fertility Of our soils