The Sauk Centre herald. (Sauk Centre, Stearns County, Minn.) 1886-current, 1913-01-09
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Crop Rotations.
BY PROFESSOR ANDREW
BOSS, AgricuIturist, Univer-
sity Farm, st. Paul.
Photo MINI. Agricultural College.

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The rotation of crops has been
strongly advocated during recent
years. Because crop yields have been
increased in some cases by rotation
many are led to believe that some
thing is added TO tie fertility of the
soil by crop rotation alone. Nothing
could be farther from the truth il
fact it is likely that the aggregate
amount of plant food is more quickly
exhausted by rotating the crops than
by single cropping, provided no ma
nures or fertilizers are used in eithe,
case.
That yields are temporarily stinu
lated by rotation is we'll shown in the
results from the crop rotation plot
at University Farm. Wheat growI
continuously he's yielded 1873 bushei.
per acre for a te1-year period In tn
three-year rotation for the same pc
Rod it has yielded 20.6 bushels. Corn
has yielded 27.5 bushels an acre
where grown continuously and 46.:
bushels where grown in a three-year
rotation of wheat, clover, and corn
The yield of hay on continuous mead
ow is II tols and in the three-yeaI
rotation 81 tons an acre. The yields
are larger with each class of crops in
rotation. The very fact that the
yields are larger suggests that more
plant food is taken from the soil in
producing them No plant food is
added by the growing crops except
that nitrogen may be gathered from
the air in the soil spaces by the bac
terra on the roots of the clover plants.
All other elements of fertility are
more rapidly exhausted by the larger
crops grown on the three-year rota.
ton fields. Doubtless the bacteria
logical and physical condition of the
soil is improved by the change OF
crops in rotation, thus accounting fol
at least a part of the increased yield.
but it is probable that unless manures
and fertilizers are supplied the yields
ins the three-year rotation without
manuring the land in the following
years will decrease. Poor soil condi
lions and correspondingly poor plant
growth is even now noticed in the
clover and corn crops.
In a five-year rotation where eight
tons per acre of barnyard manure are
applied once in five years, wheat has
averaged 27.4 bushels per acre during
the ten-year period mentioned above,
corn GLIB bushels and hay $50 tons a..
acre.
1t will be noticed that the yields
are materially increased by the use
of manures. The aim in a well bas.
anced rotation should be to return in
the manure the elements removed b.
the growing crops. For every pound
of nitrogen, PHOSPHORUS, potash or
other material taken from the soil
for crop growth a pound must be re-
turned If the normal supply is to be
maintained.
Most of our farm crops will take
from the soil yearly from twenty-five
to 100 pounds of nitrogen, about twen-
tv-fve pounds of phosphoric acid and
thirty-five to sixty pounds of potash
Any rotation scheme to be correct
must provide for replacing these ma
terials. Barnyard manures offer the
best agency for this supply. 1t may
be that in years to come it will be
necessary to add mineral fertilizers
such as PHOSPHORUS, potash. lime, etc.
AS rotations for the maintenance OF
production the following are suggested:
Three-Year Rotation.
First year: Grain-sown to red
clover eight pounds per acre.
Second year: Glover hay, two
crops-plowed in fall-top dressed in
fall or winter with six tons per acre
of barnyard manure evenly applied.
Third year: Corn.
Five-Year Rotation.
First year: Grain, seeded tos tim
othy eight pounds and clover six
pounds. 1s-e,@, :.
Second year., Timothy and clover
hay, two crops.
Third year; Pasture. ploWed in fall
top dressed with eight tons per
acre of barnyard manure. I.
Fourth year: Corn.
Fifth year: Grain.
Time can well be spent during the