428 Report of the Department of Field Crops of the 



the relative efficiency of the potato formula and the l. i. 



FORMULA. 



The proportions of plant food in these formulas are quite differ- 

 ent, the phosphoric acid being only one-half in the former that it 

 is in the latter. In both seasons the L. I. Formula has returned 

 the larger yields, the superiority in 1898 not being so evident as 

 in 1897. (See Table VII.) 



THE INFLUENCE OF POTASH IN THE FERTILIZERS. 



A popular notion widely prevails that potash manures are espe- 

 cially required by the potato crop. This view is probably based 

 upon the fact that the potato plant takes more potash than some 

 others grown agriculturally. Doubtless the marked effect of ashes 

 in some instances has led to the belief that potash is often seriously 

 deficient in ordinary soils, when as a matter of fact ashes modify 

 fertility in ways not wholly attributable to the potash they contain. 



It is widely noticeable that the most popular fertilizer mixture 

 in use on Long Island contains more potash than nitrogen or 

 phosphoric acid. This may be in accordance with the real de- 

 mands of Long Island soils, but in view of the preponderant in- 

 fluence of phosphoric acid as often observed in so many localities, 

 the economy of such an abundant use of potash is certainly open 

 to question. Because of the doubt, it was decided to test the 



* From Fleet and Hallock plats. 



