438 SOUTHERN FIELD CROPS 



because of the removal of large amounts of fertilizing con- 

 stituents, but chiefly because the crop is subject to several 

 very destructive diseases, which, after being once intro- 

 duced into the soil, increase in injury to each successive 

 crop. 



CULTURAL METHODS 



409. How propagated. The sweet-potato is propa- 

 gated without the use of seed. The most common 

 method consists in placing the roots in beds, where, under 

 the influence of proper amounts of heat and moisture, 

 the buds or eyes develop into shoots. These shoots, 

 variously called "slips," " draws," or "sets," are -the 

 means by which the greater part of the acreage is grown. 

 A second method consists in cutting sections of vines from 

 plants produced by slips and in setting these vines in the 

 field rather late in the season. A third method, seldom 

 employed, consists in cutting the potato into small pieces 

 and planting these sections just as one would plant Irish 

 potatoes. 



410. Bedding sweet-potatoes. About six weeks before 

 setting the slips in the field, the enlarged roots are placed 

 in specially constructed beds, for the purpose of stimulating, 

 by means of heat and moisture, the development of buds 

 and shoots. 



The source of heat throughout the greater part of the 

 United States is fermenting stable manure. However, 

 flue heat is employed in the trucking region of New Jersey, 

 Maryland, Delaware, and Virginia, and occasionally else- 

 where. 



411. Manure bed. A bed to be heated by manure 

 is usually made as follows : In a well-drained, sheltered 



