unless placed in a large body in a deep, close
mow that excludes the air. Some farmers use the latter method
successfully, but the experimenter with the cowpea usually will fail,
and should prefer thorough field curing, at the risk of some damage
from rain and sun. The leaves are the most nutritious part of the
plant, excepting the seed.

As a Catch Crop.--A leading use of the cowpea is that of a catch crop,
either between other crops or in a growing crop, such as corn. Early
maturing varieties can be brought in between main crops of the rotation
in warm latitudes. The growth prevents the leaching of plant-food,
shades the ground, adds nitrogen to the soil, smothers weeds, and
produces material that is valuable as feed for livestock or an addition
of organic matter to the soil. When the time that can be devoted to the
crop is short, an early variety should be selected because its vines
are far more valuable to the soil than an equal volume of a
rank-growing variety that is not near maturity.

[Illustration: The cowpea seeded at the last cultivation of corn in the
Great Kanawha Valley, W. Va.]

If this legume were used whenever opportunity afforded along the
southern border of our northern states, and throughout the south, the
faded color of soils, resulting from leaching rains, would be replaced
by the darker colors that mark the presence of rich organic matter. It
is one of nature's best allies in the maintenance of soil fertility.

CHAPTER XI

OTHER LEGUMES AND CEREAL CATCH CROPS

The Soybean.--The soybean is gaining a place among the valuable legumes
of the United States, and the acreage is increasing as its merits
become known to all. Its northern limits of profitable production are
much farther north than those of the cowpea, and approach those of
corn. In the south it is gaining friends. Some of the advantages of the
soybean over the cowpea, as found by the Tennessee station, may be
stated as follows:

1. Greater seed production in case of fertile soils.

2. Less sensitiveness to cold in spring and fall.

3. Greater feeding value of the seed.

On the other hand, a stand of cowpea plants is surer in the case of
soils that crust, and germination runs higher. Its climbing habit makes
it better suited for growing with corn for forage. A less amount of
leaves is lost in curing.

Fertility Value.--There are so many varieties of the soybean and the
cowpea, and adaptation to soil and clim