232 POTATOES 



Varieties. The so-called "yam" of the South has sweeter 

 and softer flesh than the "Jersey sweets." The true yam is a trop- 

 ical plant quite different from the sweet potato of this country. 



Common varieties of the soft, sweet type are Dooley, Southern 

 Queen and Georgia. Popular varieties of the firm Jersey type 

 are Nansemon, Big Stem and Red Jersey. Markets favor certain 

 varieties and the kind grown should be suited to the particular 

 market for which the crop is grown. 



Soils and Fertilizers. Light sandy soils are well suited 

 to the sweet potato. If the soil is very loose and open, and 

 the subsoil is heavy so the moisture will be retained, the condi- 

 tions will favor a good crop. Too much organic matter in the soil 

 tends to develop the vines at the expense of the roots. For this 



FIG. 166. Bedding sweet potatoes under sash in early spring to produce the plants for 

 setting in open fields much later. (New Jersey Station.) 



reason the use of green manure and barnyard manure on sweet 

 potato fields should be very limited unless the soil is very deficient 

 in humus. Crimson Clover is often grown in rotation with and 

 used as green manure for sweet potatoes. 



It is well to use commercial fertilizers in growing sweet pota- 

 toes. From five hundred to eight hundred pounds per acre of the 

 following mixture is recommended: Tankage, 300 pounds, dried 

 blood, 100 pounds, acid phosphate, 400 pounds, and muriate of pot- 

 ash, 200 pounds. This should have a formula of about 2}^: 9:10. 



Preparation of Soil. Sweet potato fields should be plowed long 

 enough before planting to allow the soil to settle. After plowing 

 it may be harrowed several times to help sprout the weed seed, 

 warm the soil and thoroughly aerate it. If the soil is well drained 



