SOIL EROSION IN THE SOUTH. 19 
more of very loose, incoherent soil. These freezes and thaws are 
often followed by heavy rains which sweep away this loose surface 
layer. This process occurs repeatedly during the winter, and as a 
result large quantities of surface soil are removed. This soil is not 
protected from the action of winter rains like the soils of more north- 
erly climates, where the soil is frozen during practically the entire 
winter, so that the rain can not remove the soil mantle. In addi- 
tion, the precipitation in more northerly regions is largely in the 
form of snow, which melts gradually in the spring and is absorbed 
by the soil, instead of running off over the surface. 
Terracing is practiced in the southern Piedmont region, and the 
destruction of the soil is thus greatly reduced. Since the precipita- 
tion is mainly in the form of rain, the soil must be made to absorb 
as much as possible. This can be done only by employing terraces 
and the other methods already described. Plate VI shows a well- 
terraced field in Piedmont Georgia. 
One of the peculiar soil conditions encountered in many sections 
and most conducive to destructive erosion is a surface layer of heavy 
soil material, varying from 6 inches to several feet in thickness, 
underlain by sandy material. Erosion on this type of soil produces 
enormous gulches, 10 to 50 feet deep and several hundred feet wide, 
sometimes extending for 1 or 2 miles. They begin in the hills adjoin- 
ing the lowlands, and by constant undercutting and caving push well 
back into the hills. They are very difficult to stop and often work 
their way across roadways, farms, forests, and even building sites. 
It is problematical whether the progress of these gulches can be 
entirely checked in any profitable way. However, it may be greatly 
retarded by continually dumping debris, brush, or other material into 
the gully, by planting wild honeysuckle around the head and sides 
and young pines or other trees in the mouth. Much soil material 
will thus be retained and in time the eroded area may be reclaimed. 
This type of gully is shown in Plate VII, figures 1 and 2. Sandy 
phases of the Orangeburg and Cecil soils suffer from this type of 
erosion most frequently. 
Similar erosion is encountered in western Tennessee and northern 
Mississippi, but in a different type of soil. Here the most destruc- 
tive erosion occurs in areas of silty soils. While the destruction is 
as great and the devastation possibly more complete, the hope of 
reclamation is not so remote. For one thing, the depth of the gullies 
does not generally exceed 15 feet, because more resistant material 
is encountered at about this depth. The sides are slightly less 
abrupt and there is a better opportunity for the growth of wild 
plants or even the gradual reclamation by reforestation. 
Some of the lands have been stripped of their natural growth of 
timber by rapid erosion. Frequently a surface layer of heavy soil, 
less than a foot thick, covers a subsoil of much lighter material, in 
