6 SOILS OF THE EASTERN UNITED STATES. 



The principal limitation upon the extensive occupation of the 

 Hagerstown clay lies in its tendency to erode readily unless the sur- 

 face soil is protected by grass covering or by some other form of 

 vegetation, particularly during the torrential rains of the winter 

 months. The stiff and impermeable character of the surface soil 

 and subsoil renders the absorption of the rainfall rather slow. As 

 a result, with sudden showers, a large proportion of the rain falling 

 upon the land flows across its surface and is not absorbed by the 

 soil. Under such circumstances, particularly when the subsoil is a 

 stiff, heavy, and compact clay, the erosion of the fertile surface soil is 

 rapid and destructive. In consequence the prevention of erosion 

 upon the type constitutes one of the chief problems in its wider occu- 

 pation and also limits the area of the lands which may be used for 

 the cultivation of any tilled crops. 



The presence of outcropping ledges of rock and of especially stony 

 areas over a considerable portion of the Hagerstown clay, also con- 

 stitutes a limitation upon the uses to which the type may best be put. 

 These areas, while not constituting more than 25 per cent of the total 

 area of the type, are of wide general distribution throughout its 

 occurrence. The presence of the stones, and particularly of the rock 

 ledges, interferes with the tillage of the type and, in consequence, such 

 areas are best devoted to the production of bluegrass, which grows 

 luxuriantly and which constitutes an excellent pasturage. Thus 

 through its topographic condition, and through the presence of an 

 excessive amount of stones, a portion of the type should be devoted 

 to pasture rather than to tillage. 



The Hagerstown clay occurs through a considerable range of cli- 

 matic environment. The more northern areas are generally devoted 

 to the production of corn, wheat, oats, and grass, while in the more 

 southern areas the type is given over to the production of corn and 

 cotton, with small areas of wheat and grass. It is probable that even 

 in the more southern areas the better farm practice would be to 

 eliminate cotton, which is not grown to particularly good advan- 

 tage, and to occupy this type for the production of grain and forage 

 crops. 



IMPROVEMENTS IN SOIL. EFFICIENCY. 



The prevention of excessive erosion over the more steeply sloping 

 portions of the Hagerstown clay constitutes one of the most im- 

 portant needs of this soil. All areas which have a slope in excess of 

 10 degrees should either be left in forest or should be placed in blue- 

 grass sod to furnish grazing, and at the same time to prevent exces- 

 sive erosion. There are, however, many areas with less slope which 

 are subject to serious annual washing. Such areas would be im- 

 proved by filling the gullies already formed with brush and other 



