POTATOES 



123 



Keitt found cottonseed meal slightly snioerior to nitrate of 

 soda as a source of nitrogen, while Vorhees obtained much 

 better results from nitrate of soda than from cottonseed meal. 



Shiver concludes that sulphate of potash is apt to give larger 

 yields than muriate, although either will aid in better production, 



Stuckey's experiments show that while nitrogenous fertilizers 

 gave heavy yields of vines, they may or may not give large yields 





Fig. 



I. — Sweet-potato slips ready to be drawn. 

 Truck Exp. Sfalioii, 'Bulletin Id. 



-Virginia 



of tubers. In the same work it was found that acid j^hosphate 

 alone did not increase the yield of potatoes. 



Varieties.^ Varieties Avhich gave the largest yields are not, 

 as a rule, desirable for table use, and are usually grown for 

 stock feeding. In the north, the sweet potato is usually boiled, 

 and for this reason a variety high in starch is more in demand 

 than the sugarv-fleshed varieties, which are used so generallv in 

 the South. 



Two varieties of the dry or mealy type are Big Stem Jersey 

 and Yellow Jersey. The soft flesh sorts, Avhich are more popular 

 in the South, are Nancy Hall, Triumph, Porto Rico, and Dooley 

 Yam. Bermuda is the best representative of the larger type 

 which is grown exclusively for livestock. 



