The Ordway new era., 1910-05-27
Crop R0t0Hon

According to their method Of
growth and general effect upon the
soil, field crops may be divided into
three classes: Perennial grass and
legumes, cultivated crops, and small
grains and uncultivated annual forage
crops. The best results are obtained
by alternating these three classes OF
crops with more or less regularity, In
place OF raising one kind continuous
ly.
Perennial grasses and lcgumcs. as Il
class, are soil protectors, soil renew
ers and soil builders. They leave "a
considerable amount OF vegetable
matter Ia the soil, which. by decay,
furnishes good supplies OF plant food
for crops which follow. Through sew
eral years growth these crops develop
rather deep, penetrating root systems.
which gather certain mineral foods in
the lower layers OF the soil and leave
them In the upper layers when they
decay. These ,iccaying roots also I'm
prove the physical condition OF the
soil by opening it up and increasing
Its capacity to absorb and retain mOis-
ture. As Is we'll known, alfalfa. the
clovers. and other legumcs not only
possess the good characteristics of the
grasses, hut, in addition, have the
ability (through symbolic bacteria) OF
actually adding nitrogen to the soil
from the air. One or these legumcs
should by all means be added to every
rotation.
Cultivated crops, through the tillagc
and cultivation they receive, aeratc
and pulverize the soil and conserve the
moisture. This results in conditions
favorable for the development OF bac.
terra 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
annual forage crops draw heavily
upon soil fertility and soil moisture.
They reduce the organic matter rapid
ly, especially II the straw is not all
removed. Many soils, after a 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
turnover M bard luntps and clods]
when plowed. Tie good tilth OF vir-
gin grass lands Is more or less COM
pletcly restored to worn out soils
when they have been put into II
legume or grass for sufficient
length Of time.
AS Il general rule cultivated crops.
like corn and potatoes, should follow
the grass crops. They have the ability
to get their food under more adverse
circumstances than some Of the
grains, like barley and wheat. and the
constant stirring helps greatly to
subduc the sod and leave Il supply OF
easily 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 injurc the grains, and they
have prepared 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 fertility and organic mat
ter, and Is rather hard and compact.
The grass crops will largely correct
these conditions. If nurse crops are
used in seeding the land, the grain
crop comes in the right place to be
used for this purpose.
D. W. FREAR,
Colorado Agricultural College, Fort