Vegetables with Edible Tubers or Roots 255 



sandy soil should be chosen, well fertilized and plowed 

 deeply. A finer grade of sweet potato for table use may be 

 produced by plowing shallow and using less fertilizer or 

 none at all. 



Fertilizer. 



The proportion of fertilizer ingredients should be as 

 follows : ammonia, 5 per cent ; available phosphoric 

 acid, 7 per cent; potash, 9 per cent. Use 800 to 1200 

 pounds to the acre. If the soil is rich in nitrogenous 

 matter, less of this element should be used, or if very rich, 

 it should be omitted altogether. If the potatoes are 

 intended for table use, the amount of fertilizer should be 

 less than when grown for stock feed or for shipping. 

 Sulfate of potash is preferred as a source of potash. 



The following quantities of fertilizers will give the 

 amounts of each element called for in the formula : 



Ammonia 



Pounds to the Acbe 



500 to 800 cottonseed meal , or 

 350 to 500 dried blood; or 

 200 to 300 nitrate of soda ; or 

 150 to 250 sulfate of ammonia. 



Phosphoric acid 550 to 800 acid phosphate. 



Potash 



150 to 225 sulfate of potash ; or 

 200 to 300 nitrate of potash ; or 

 500 to 700 cottonseed huU ashes. 



Propagation of the sweet potato. 



To obtain early sets, or " draws," in subtropical climates, 

 the whole potatoes should be placed in a hotbed or cold- 

 frame and covered with an inch of soil, six or seven weeks 



