WIND 



i8i 



snow is an important factor in causing erosion is evidenced by 

 the fact that for a 5-year period an average of about 172 cubic 

 feet of soil, expressed on an air-dry basis, was deposited from 

 area A and 82 cubic feet from area B. As would be expected, 

 however, there is appreciably less sediment deposit per unit of 

 run-off from melting snows than from summer rain storms. 



Fig. 57. — RANGE LAND STRIPPED OF ITS GOOD SOIL. 

 The remaining grass hummocks mark the depth to which the rich surface soil has been removed by 



wind and water erosion. 



Wind. — In addition to the conspicuous action of the gully 

 and " shoestring " type of erosion, the removal of soil caused 

 by the action of the wind is often considerable. After the de- 

 struction of the vegetative cover, either entirely or in part, the 

 wind movement becomes highly effective in the translocation 

 of soil (Fig. 57). Almost everywhere the wind is sufficiently 

 strong to carry from one place to another those soil particles 

 that are not firmly bound by vegetation and ultimately to de- 



