Montour American. (Danville, Pa.) 1866-1920, 1902-03-13
ROTATION OF CROPS.
t1fects Upon the Humus Contents
and Fertility of the Soil.

tJnetts Upon the
and Fertility of the Soil.
The Ohio station has made a study
of the application of fertilizers in ro-
tative croppings. Their experiments
indicate that with crops grown cOntin-
uOusly the cost of the fertilizer has
been greater than the value Of the crop
produced. Where grains have been
grown in rotation with clover the cost
Of the fertilizer has beer recovered,
with a margin to spare. In growing
cereals continuously the recovery Of
the fertilizing ingredients applied is
never in excess of 60 per cent. Nitro
gen appears to be the element first eI-
hausted in continuous grain culture.
Grains grown in rotation with clover
recover the nitrogen applied and part
Of that stored up by the clover. The
conclusion is reached that at the pres
ent prices for grains and fertilizers
the use Of commercial fertilizers and
even of barnyard manure, if valued on
the same basis, is not profitable on
wheat, oats and corn except when
those crops are grown in a systematic
rotation with clover or some other nj
trogen collecting crop. The poorer the
soil the smaller the probability Of prof
liable crops by the use Of artificial fer
tiliZers.
The Minnesota station has studied
the effects of the rotation Of crops up
on the humus content as well as upon
the fertility of the soil. Wheat grown
continuously for four years removed
annually twenty-five pounds Of nitro
gen per acre, while 146 pounds more
were lost. This nitrogen was lost by
the oxidation Of the humus, by deni-
trifcation chemically, by windstorms
and through the loss of nitrates by
drainage" AS crop Of spring wheat
occupies the ground during a short por-
ton of the year, it may be seen that
during the greater part of the year the
other factors are at work In eliminat-
ing this element.
In n rotation of wheat, clover, wheat
and oats an average Of 17S pounds OF
nitrogen per acre was removed annu-
ally. yet there was gain for four
years over and above this amount Of
245 pounds of nitrogen. This nitro
gen, it is believed, has been gained
largely by the clover from the free nj
trogcn of the air" In this rotation
not only was the nitrogen and humus
content Of the soil increased, but lar
ger crops We're grown.
With corn grown continuously for four
years the soil lost annually 50 pounds
of nitrogen. OF this amount only 90
pounds were removed by the crop. The
annual loss with an oat crop grown
continuously was $50 pounds Of nitro,
gen, while only about 46 pounds were
removed by the crop. Barley removed
about 80 pounds Of nitrogen per acre,
and there were lost an additional 100
pounds.
With continuous wheat culture there
was an annual loss of 1,S0O pounds OF
humus per acre and with the continu-
Gus culture Of corn, oats and barley an
annual loss Of l 500 pounds. The plats
/ under continuous culture became light
er In color and heavier than those
where rotation was practiced. The fal,
lowing Of the land resulted in great
! loss Of nitrogen, as five times as much
was rendered available as the crop fol
lowing could utilize, and the excess
was lost by teaching. The gain with
clover in rotation was five bushels of
wheat and seventeen bushels Of corn
per acre.