SOIL EROSION 



361 



3. Changes of Color. Erosion almost invariably results in a 

 change of color of the soil. If the soil is brown, yellow or grayish 

 yellow, erosion produces a yellow or reddish color, depending wholly 

 on the color of the subsoil. On the Piedmont Plateau and some 

 other residual soil areas the color becomes very red, due to exposure 

 of the subsoil. 



KINDS OF KROSIOX 



Two somewhat distinct types of erosion are recognized, sheet 

 erosion and gullying. 



I. Sheet Erosion 



Water flowing over a uniform slope removes approximately the 

 same amount of soil material from all parts. Sheet erosion is the 

 source of far greater loss than gullying. The latter quickly and 

 completely ruins small areas, but the former reduces the produc- 

 tiveness over large areas to the point of unprofitable returns. 



Methods of Prevention and Reclamation. 1. Application 

 cf Limestone. Limestone in time renders the soil more porous 



1 in Marrli, photngrnphml in 



bv producing granules. This lessens erosion, because the soil i- 

 more absorbent and the heavier compound granules ;ire more difti- 



