SOIL EROSION IN THE SOUTH. 13 
N. C. It differs from the others in that the terrace lines are not 
level, but contour the field at a grade of l\ inches to 14 feet. This 
terrace is a broad bank of earth with gently sloping sides. It is con- 
structed along the lines laid off by back furrowing and pulling the 
soil to this line, thus forming a low dike. This terrace has been 
described in detail in a Government publication. 1 It gives a gradu- 
ally sloping side both above and below its highest point, so that culti- 
vation may be carried on across the ridge in any direction. While 
providing protection to the land it also eliminates the waste land and 
breeding places for insects afforded by the weeds or grass growing on 
the terrace ridges. For most agricultural lands it is the ideal ter- 
race, but it may not be suitable for some soils of a light character. 
OTHER METHODS OF PREVENTION. 
In addition to the use of terraces to prevent washing of the soil 
it is generally advisable to plow deeply. By plowing deeply the soil 
is so loosened that the rate of absorption becomes much greater and 
the land is enabled to take care of a heavier sudden rainfall. The 
same thing is accomplished by incorporating organic matter in the 
soil or by use of tile drains. In fact, any method that will assist 
in the efficient drainage of a soil will also do much toward the pre- 
vention of excessive erosion. The interstitial spaces become larger 
in a well-drained soil, so that the movement of water through the soil 
is more rapid. Hence a heavy precipitation may be absorbed as 
rapidly as it falls. 
Prevention of erosion is accomplished by having some vegetation 
cover the entire surface of the soil. This offers resistance to the 
water flowing over the surface and retains it long enough for the 
soil to absorb larger quantities than would be possible under clean 
culture. The expedient of alternating strips of cultivated soil with 
grass strips is sometimes resorted to, and on moderately rolling land 
this is fairly effective. Again, land that would be unsuitable to clean 
culture may be utilized for orchards with a cover crop on the soil. 
The use of winter crops should find application especially in the 
Southern States. The winter precipitation, which constitutes a 
large part of the total, is largely in the form of rain, and in many cases 
it falls on land barren of any crop. The use of rye or some winter 
crop would be of great advantage in holding the soil and preventing 
the destructive erosion resulting from the winter rains. 
The method of using hillsides for orchards and maintaining a grass 
cover crop has given rise to considerable discussion as to the relative 
value of the orchard with such a crop or with clean culture. As a 
means of preventing wash, the grass is effective, but the general 
1 Cir. No. 94, Bureau of Plant Industry, U. S. Dept. Agr. 
