I 7 6 AGRICULTURAL ECONOMICS 



The gullies in the field act as drainage ditches. The land between 

 such gullies drains too rapidly, the water-table is lowered, and it is 

 difficult for the crop to obtain sufficient water for proper growth or 

 to withstand even a moderate period of drought. As these gullies 

 occur on hillsides, the natural drainage is ample, if not excessive, so 

 that the additional drainage furnished by the gullies is a positive 

 disadvantage. 



This removal of the best soil material and the impairment of that 

 remaining results in the occurrence of much waste land. In the South 

 the abandonment of land is traceable more often to erosion than to 

 any other cause. In some of the states vast areas, amounting occa- 

 sionally to 50 per cent of the arable land of those sections, have been 

 abandoned to the ravages of water-wash. 



Throughout the South erosion is probably worse than in other 

 sections of the country. In the Atlantic Coast states the worst type 

 is encountered in the Piedmont section. It is less marked in the 

 mountains, probably because agriculture is less extensively practiced. 

 Erosion is very marked in some of the states of the Mississippi Valley, 

 some of the worst eroded sections of the country occurring in the hills 

 of these states. 



The erosion hi the Piedmont province is apparently more pro- 

 nounced in the more southerly states. This is probably due largely 

 to the climatic conditions. During the winter the temperature is not 

 low enough to cause deep freezing, and cold periods are of short dura- 

 tion. The soil is not protected from the action of winter rains like 

 the soil of more northerly climates, where the soil is frozen during 

 practically the entire winter, so that the rain cannot remove the soil 

 mantle. In addition, the precipitation in more northerly regions is 

 largely hi the form of snow, which melts gradually in the spring and 

 is absorbed by the soil instead of running off over the surface. 



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, under- 

 lain by sandy material. Erosion on this type of soil produces enor- 

 mous gulches, 10-50 feet deep and several hundred feet wide, 

 sometimes extending for i or 2 miles. They begin in the hills ad- 

 joining the low lands, and by constant undercutting and caving push 

 far 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 en- 



