POTATOES. 55 



produces a yet larger increase when used in conjunction with both 

 phosphoric acid and nitrate of soda. 



**A potato fertilizer for such a soil as this should contain nitrogen, 

 phosphoric acid and potash, and I should judge that materials fur- 

 nishing per acre, nitrogen, 30 lbs.; phosphoric acid, 60 lbs.; and potash, 

 100 lbs.; might give a profitable crop." 

 By Frank Wheeler, Concord. Soil — Sandy loam. 



"Potash appears to have been the element *in minimo.' Even 

 when used alone it produced a profitable increase. But its beneficial 

 effects are greater with either of the other elements than alone, and 

 greatest with both the others." 



By L. W. West, Hadley. Soil — Moderately heavy loam. Nitrogen 

 produced a gain of $5 35, phosphoric acid a loss of $3.39, and potash 

 a gain $38,83. 



"The superiority of the plots which received potash was eviJent 

 from an early stage in the growth of the crop. 



"This soil stands in greater need of potash for potatoes than of 

 either of the other ingredients of the fertilizer used. It is significant 

 that all the requirements of corn on similar soil, as shown by the experi- 

 ments of 1889 and 1890, were the same. In view of the confirmatory 

 results of the experiments of three successive years upon it, a very 

 marked deficiency of potash in this soil can not be reasonably doubted." 



1892. 

 General Summary. The average from all the preceding experiments 

 shows that nitrogen produced 10.74 bushels increase, phosphoric 

 acid 10. 1 1 bushels, and potash 41.55 bushels increase. 



"It will be observed that the potash of the fertilizers of every 

 experiment save one (Shelburne), proved much more beneficial in its 

 average effect upon the crop than either nitrogen or phosphoric acid, 

 and the indication is, therefore, that it should be relatively more abun- 

 dant in fertilizers especially designed for this crop than is usually the 

 case." 



At the Station Grounds, at Amherst, North Acre. Bulletin 

 No. 18, 1892, Soil — Warm medium loam. Nitrogen and phos- 

 phoric acid produced a loss; potash a gain of $13.60. 



"These comparisons make evident the fact that for potatoes, as 

 for corn last year, potash should be a prominent ingredient of the fer- 

 tilizer used. Neither nitrogen nor phosphoric acid gave results of any 

 great importance, while potash alone, and in every combination, pro- 

 duced a profitable increase." 



