r conditions of most soils.

The mixing of heavy applications of coarse manures or organic matter
with light sandy soils may make them so loose and open that they will
lose moisture rapidly. When this practice is necessary the land should
be rolled after the application of the manure.

METHODS OF CROPPING AND SOIL WATER

Constant tillage hastens the decay of organic matter in the soil.
Hence any method or system of cropping which does not occasionally
return to the soil a new supply of humus tends to weaken the powers of
the soil toward water.

All of the operations and practices which influence soil water also
affect the other conditions necessary to root growth; namely, texture,
ventilation, heat, and plant food, and those operations and practices
which properly control and regulate soil water to a large degree
control and regulate soil fertility.

SELECTION OF CROPS WITH REFERENCE TO SOIL WATER

While climatic conditions determine the general distribution of
plants, the amount of water which a soil holds and can give up to
plants during the growing season determines very largely the crops to
which it is locally best adapted.

With crops that can be grown on a wide range of soils the water which
the soil can furnish largely determines the time of maturing, the
yield, and often the quality of the crop. With such a crop a small
supply of water tends to hasten maturity at the expense of yield.

The sweet potato, when wanted for early market and high prices, is
grown on the light sandy soils called early truck soils. These soils
hold from five to seven per cent, of water. That is, the texture is
such that during the early part of the growing season one hundred
pounds of this soil is found to hold an average of from five to seven
pounds of water under field conditions. This soil, holding little
water, warms up early and thus hastens growth. Then as the warmer
summer weather advances, the water supply diminishes, growth is
checked, and the crop matures rapidly. On account of the small amount
of water and the early checking of growth, the yield of the crop is
less than if grown on a soil holding more water, but the earlier
maturity makes it possible to realize a much higher price per bushel
for the crop. A sweet potato grown on such a light soil is dry and
starchy, a quality which brings a higher price in the northern markets
than does the moist, soggy potato grown on heavier soils which contain
more water and