246 Fertilizers 



is also considered. Any excess of nitrogen over this 

 amount seems to contribute toward a larger, rather oblong, 

 rooty growth of tuber, and to injure cooking quality. In 

 growing crops for the general market, however, larger 

 applications of nitrogen are demanded, and experiments 

 have shown that organic forms are preferable to soluble 

 forms, though the climate and season largely influence 

 this point. In northern sections, and in cold seasons, the 

 soluble forms are more useful than in the warmer climate 

 and longer seasons of the South. 



There is no question, however, that commercial fer- 

 tilizers can be depended upon to produce maximum crops 

 of sweet potatoes, and at much smaller cost than with 

 yard manure. 1 Results reported by the Georgia Ex- 

 periment Station 2 indicate the following formula as an 

 excellent one for sweet potatoes, though, as there stated, 

 " the amounts that can be used vary considerably, depend- 

 ing upon the character of the soil the richer the land in 

 humus, the greater the quantity that can be safely used." 

 " Thin soils will, of course, only stand very moderate ma- 

 nuring, and necessarily produce a very small yield." The 

 formula consists of 



Acid phosphate 320 Ibs. 



Cotton-seed meal 360 Ibs. 



Kainit 640 Ibs. 



This formula will furnish about 25 pounds of nitrogen, 

 50 of phosphoric acid and 80 of potash, and, according to 

 the bulletin, will produce a yield of potatoes from 200 to 

 400 bushels to the acre, depending upon the season and 

 variety of potatoes planted. Experiments at the Georgia 



1 Bulletin P, New Jersey Exp. Sta. 



2 Bulletin No. 25, Georgia Exp. Sta. 



