Soils 59 
difference between the surface and the subsoil is not great, 
the subsoil being in many cases just as fertile and mellow 
as the upper laver. In humid regions, on the other hand, 
the subsoil is often compact and, on account of its lack 
of aération, seems “dead” when brought to the surface. 
Such soils sometimes require a number of years to be- 
come fertile. Sugar-beets, on account of their deep pene- 
tration of roots and their high air requirement, find their 
best growth only in soils having a subsoil condition that 
is favorable. Any hardpan layer is particularly detri- 
mental. 
SOIL TEXTURE 
Soils vary greatly in the size of particles composing 
them. Some are made up almost entirely of coarse parti- 
eles; others are composed entirely of fine. “Most soils, 
however, contain some fine and some coarse grains, the 
relative number of each determining the texture, which 
cannot be modified by the farmer. The texture of the 
soil has a great influence on the method of tillage as well 
as on a number of its properties, such as the water-hold- 
ing capacity, the circulation of air, and the availability 
of plant-food. These all help in determining the kind 
of crop that should be grown. For example, peaches and 
cherries thrive on a soil having a coarse texture; the small 
grains prefer a “ heavier” soil; sugar-beets and most other 
crops do best on soils of intermediate texture, such as the 
loams. 
The various sizes of particles composing the soil have 
been classified by the United States Department of 
Agriculture, Bureau of Soils, as follows: 
