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. 



CIuLTUKAL Methods 



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

 gated witliout 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 bj' 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 woukl plant Irish 

 potatoes. 



410. Bedding sweet-potatoes. — About six weeks before 

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

 in speciallj' 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 stalile manure. However, 

 flue heat is emploj^ed in tlie trucking region of New Jersey, 

 Maryland, Delaware, antl A'irginia, and occasionally else- 

 where. 



411. Manure bed. — A l)ed to be heated by manure 

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



