220 VEGETABLE GROWING. 



adapt it to the particular plow and to the particular 

 field, but it is certainly a great labor saving implement. 

 Among Northern sweet potato growers it is -thought 

 that it is detrimental to allow the vines to root, 

 but the idea is not prevalent in the South. Tests 

 on this subject indicate that it will not pay for the 

 trouble, except when cultivation ceases early, or the 

 crop is grown on rich ground, and a heavy rain should 

 fall soon after the last plowing. 



FERTILIZER FORMULA. 



Nitrogen . 4 per cent. 



Potash 9 per cent. 



Available phosphoric acid.. 7 per cent. 



Use 800 to 1,200 pounds of the above formula. If 

 the soil is rich in nitrogenous matter use less of this 

 element, or if very rich, omit it altogether. If the 

 potatoes are intended for table use the amount of fer- 

 tilizer should be less than when grown for stock feed 

 or for shipping. Sulphate of potash is preferred as 

 a source of potash. All fertilizers that contain 

 chlorin are said to be detrimental to the quality of the 

 potato, so we should avoid such fertilizers as kainit, 

 muriate of potash and low grade sulphate of potash. 



The following quantities of fertilizers will give the 

 amounts of each element called for in the formula. 



Element. Pounds of different material for one acre. 



f 500 to 800 Ibs. cotton-seed meal ; or 

 XT .,- I 350 to 500 Ibs. dried blood ; or 



jr en 1 200 to 300 Ibs. nitrate of soda ; or 



{ '150 to 250 Ibs. sulphate of ammonia. 



!150 to 225 Ibs. sulphate of potash ; 

 200 to 300 Ibs. nitrate* of potash ; or 

 500 to 700 Ibs. cotton -seed hull ashes. 



., / 550 to 800 Ibs. acid phosphate ; or 

 Phosphoric acid.... j 50Q to m }b& di8SO l ve d bone. 



*Nitrate of potash contains 13 to 14 per cent, nitrogen, so if it is used 

 only one-fourth of the amount of material directed to supply nitrogen 

 should be added e. g., add only 125 to 200 pounds of cotton-seed meal. 



