Semi-weekly herald., 1910-05-26
CROP ROTATION.


According to their method of growth
and general effect upon the soil, field
crops may be divided into three class
es: perennial grasses and legumes,
cultivated annual forage crops. The
best results are obtained by altornat-
ing these three classes OF crops with
more or less regularity, In place of
raising one kind continuously.
Perennial grasses and legumes, as a
class, are soil protectors. soil renew
ers, and soil builders, They leave a
considerable amount of Vegetable mat.
ter In the soil, which, by decay, fur.
crops which follow. Through several
years growth these crops develop
rather deep. penetrating root systems,
which gather certain mineral foods in
them in the upper layers when they
decay. These decaylng roots also i'm,
prove the physical condition OF the
soil by opening 1t up and increasing its
'"pa'ity w dDsoIb anu retain UlOlhtuFe.
AS is well known. alfalfa, the clovers
and other legumes not only possess
the good characteristics OF the grasses,
but, in addition. have the ability
Through symbolic bacteria) of actual.
| ly adding nitrogen to the soil from
The air. One of these legumes should
by all means be included In every ro-
tation
Cultivated crops. through the tilage
and cultivation they receive, aerate
and pulverize the soil and conserve the
moisture. This results in conditions
favorable for the development OF bac.
teria which hasten the decomposition
and chemical changes which make
plant food available. These crops tend
to deplete the fertility rather rapidly
and to reduce the organic matter
Well cultivated crops do not remove
so much soil moisture as the crops In
the other classes.
Small grains and uncultivated an.
nual forage crops draw heavily upon
soil fertility and soil moisture. They
reduce the organic matter rapidly, es.
pecially If the straw is all removed
Many soils, after few years cropping
with grains. become finer in texture,
more compact and heavier to handle
They dry out quicker than they used
to, and often turn over in Jumps and
hard clods when plowed. The good
tilth of virgin grass lands is more or
less completely restored to worn out
soils when they have been put into a
leeume or grass for sufficient
length of time.
As a general rule cultivated crops,
like corn and potatoes. should follow
the grass crops. They have the abil.
ity to get their food under more ad.
verse circumstances than some OF the
grains like barley and wheat. and the |
constant stirring helps greatly to sub |
due the sod and leave a supply OF eas.
lily available plant food for the crops |
that follow.
The grain crops should come In be. |
tween the cultivated crops and the \
grass crops The cultivated crops have |
destroyed many weeds which might |
inIure the grains, and they have pre-
pared plant food and left the soil in
good physical condition. BY the time
several grain crops have been raised |
the soil is again low in available fer
tility and organic matter. and is ra,her
hard and compact. The grass crops
will largely correct these conditions
II nurse crops are used In seeding
the land, the grain crop comes in the
proper place to be used for this pur-
pose.
d. w. FREAR.
Colorado Agricultural College. Fort