10 BULLETIlSr 180, U. S. DEPARTMENT OP AGEICULTURE. 



ing action is taking place. Soils composed almost entirely of either 

 sand or clay particles are not so good as those with a fair amount of 

 each. 



The quality of the soil is greatly impaired by the continual process 

 of erosion. Rapid leaching takes place, removing a large part of the 

 soluble salts; the surface soil is often washed down to the lowlands 

 and sometimes out to the sea; gullymg so defaces the land that it 

 becomes difficult to cultivate. The organic matter is one of the first 

 losses of eroded soils. Abandonment of the field follows, because 

 the land is considered too poor for agricultural use, having lost its 

 productiveness through the process of erosion. 



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

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

 difficult for the crops to obtain sufiicient water for proper growth 

 or to withstand even a moderate period of drought. As these guUies 

 occur on hillsides, the natural drainage is ample, if not excessiv^e, so 

 that the additional drainage furnished by the gulHes 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 amoimting 

 occasionally to 50 per cent of the arable land of those sections have 

 been abandoned to the ravages of water wash. 



THE PREVENTION OF EROSION. 



The necessity for the prevention of erosion is obvious. There is 

 every indication that the public conscience is being quickened in this 

 respect, and several wStates are beginning to appreciate the necessity of 

 conserving their soil. The State of Tennessee is making a serious 

 effort in this direction. The State geologist, with the aid of soU and 

 forestry experts, is waging a campaign of education to teach the 

 farmers how to prevent erosion and reclaim eroded lands. Some of 

 these lands with proper care can be reclaimed for agricultural use, 

 while others can be utifized for forestry. It is the function of the 

 experts to determine the best use of eroded lands in various sections 

 of the State. 



A number of papers on the subject of erosion and its prevention^ 

 point out the damage from erosion and the general means of con- 

 trolling it. 



METHODS OF PREVENTION. 



Methods employed for the prevention of erosion must embody 

 either one or two principles: They must increase the capacity of the 

 soil for absorbing water or must decrease the velocity of the running 



1 Farmers' Bui. No. 20, U. S. Dept. Agr.; HI. Expt. Sta. Cir. No. 199; SoU Kept. No. 3, lU. Expt. Sta. 



