d occur in every
well-planned rotation.

Rotation helps to maintain or increase the plant food in the surface
soil. When crops like cowpeas or clover which take mineral food from
the subsoil and nitrogen from the air, are plowed under, they give up
the plant food in their leaves, stems and upper roots to the surface
soil, and thus help to maintain or increase fertility.

Rotation tends to protect crops from injurious insects and diseases.
If one kind of crop is grown continuously on one piece of land the
soil becomes infested with the insects and diseases which injure that
particular crop. If the crop is changed, the insects and diseases find
difficulty in adapting themselves to the change and consequently
diminish in numbers.

Rotation helps to keep the soil free from weeds. "If the same kind of
crop were grown year after year on the same field, the weeds which
grow most readily along with that crop would soon take possession of
the soil." For example, chick weed, dock, thistle, weeds peculiar to
grain and grain crops tend to increase if the land is long occupied by
these crops.

Rotation helps the farmer to make a more even distribution of labor
throughout the year. This is because crops differ as to the time of
year at which they are planted and harvested.

Rotation of crops enables the farmer to provide for his stock more
economically. Live stock fares better on a variety of food, which is
more cheaply secured by a system of rotation than otherwise.

THE TYPICAL ROTATION

A typical rotation for general farming should contain at least:

One money crop which is necessarily an exhaustive crop.

One manurial crop which is a soil enricher.

One feeding crop which diminishes fertility only a little.

One cleansing crop, a hoed or cultivated crop.

CONDITIONS WHICH MODIFY THE ROTATION

There are certain conditions which tend to modify the rotation or to
influence the farmer in his choice of crops. They are as follows:

First of all the climate will set a limit on the number and varieties
of crops from which a choice can be made for a given locality.

The kind of farming which he chooses to carry on, whether stock
raising, grain farming, truck farming, or a combination of two or more
of these, or others.

Kind of soil. Certain soils are best adapted to particular crops. For
example, heavy soils are best suited to wheat, grass, clover,
cabbages, etc. Light, sandy soils to early truck, certain grades o