Ottumwa tri-weekly courier. [volume] (Ottumwa, Iowa) 1903-1916, 1909-06-24
THE SOIL MUST BE FED
Some Plain and Interesting Fig.
ures Relating to Removal of
Plant Food-The Effect.
By PROFESSOR CYRIL G. HOPKINS,
University of Illinois,

In a three-year rotation of corn,
pats and clover. let us assume yields
kf 100 bushels per acre of corn and
watts, four tons of clover and four
bushels of clover seed.
We may sow cowpeas in the corn the
last cultivation and possibly produce a
ratch crop of one-half ton to the acre.
We will plan to husk the ear corn
and leave the stalks on the land to
be disked down for seeding oats and
clover.
The oats should be cut as high as
possible and the threshed oat straw
should be spread over the land either
before or after rotting, as may be
found best.
The third year the clover may be
clipped perhaps two weeks before hay
ing and left lying on the land, the
second crop being harvested later for
seed, using a buncher attached to the
mower so as to avoid raking.
The threshed clover straw should be
spread over the land, and if rock
phosphate is used it may be applied
and plowed under with all of the
accumulated organic matter in prepa-
ration for the following corn crop
which would begin the second rota-
ton.
These three crops removed about 173
pounds of nitrogen, while the clover
and cowpeas returned about 1872 pounds
Of nitrogen and, together with the corn
stalks and oats straw, furnished a
large supply of humus.
This is system of grain farming
planned to maintain the supply of
humus and nitrogen.
If the yields are cut in two the basis
of the system remains the same.
Many other rotations for grain farm
Ing might be followed, but in all cases
liberal use must be made of legume
crops, catch crops, other green manure
crops and crop residues in order to
supply humus and nitrogen.
In live stock farming take a five
year rotation, including corn two
years, oats with clover and timothy
seeding the third year, and two years
of clover and timothy, using one year
for hay and the other for pasture, as
Stunning the same yields as before.
Shock one-half of the corn or put
1t in the silo; husk the other half and
use the oats straw for feeding and
bedding.
The four crops will remove from the
ooii dOoul 1oo5 pouIluS VI HllTOSeI ana
the clover hay will contain about 1901
pounds, which we assume was secured
from the air, making 4S9 pounds of
nitrogen in the total feed and bedding.
If one-half of this is recovered in the
manure and returned to the land there
would be deficiency of 1874 pounds
But two thirds Of the nitrogen can be |
recovered by feeding upon cement floors
and a liberal use of straw and shredded
fodder for bedding, thus reducing the
deficiency to 43 pounds.
The pasturing may gain IL pounds of
nitrogen. By feeding more or less
upon the fields and by leaving con-
siderable clover in the pasture to
serve as green manure this small
deficiency can be replaced, but to main
tain or increase the supply of humus
and nitrogen in the soil is by no
means an easy problem, even with live
stock farming.
Keep in mind these two words, pros
phorus and humus.
If these are increased in the soil
The farm will be growing richer and
more productive, but whoever removes
the phosphorus or destroys the humus
more rapidly than they are replaced
Hill have poorer land year by year with
poverty as the only future for the chill
aren who continue the same ruinous
system.
A 100-bushel crop of corn requires 90
pounds of phosphorus; 50-bushel crop
of wheat, 16 pounds: a. Atom crop of
cloyer 20 pounds