New York Agricultural Experiment Station. 429 



effect of varying quantities of this ingredient on the productive- 

 ness of the potato crop. 



Four formulas were used on four acres of land, one on each of 

 four farms. The percentages of nitrogen and phosphoric acid 

 were the same in each formula, the proportion of potash being 

 respectively per cent, 3.5 per cent, 7.0 per cent and 10 per cent. 

 On all fertilized plats the fertilizer was applied at the rate of 1,000 

 lbs. per acre, so that the amount of potash per acre varied from 

 none to 100 lbs. 



Table VIII. — Kesults from Potash Test Formulas. 



No. of Yield. Gain, 



plats aver- Plant food applied per acre. 



aged. Large. Total. Large. Total. 



Bu. Bu. Bu. Bu. 



8 No fertilizer 123.0 149.9 



8 40 lbs. nitrogen, 80 lbs. phos. acid 



and no potash 179.9 204.0 56.9 54.1 



8 40 lbs. nitrogen, 80 lbs. phos. acid 



and 35 lbs. potash 177.3 203.7 54.3 53.8 



S 40 lbs. nitrogen, 80 lbs. phos. acid 



and 70 lbs. potash 178.4 202.6 55.4 52.7 



8 40 lbs. nitrogen, SO lbs. phos. acid 



and 100 lbs. potash 180.8 203.5 57.8 53.6 



Table VIII shows that the fertilizer without potash was as 

 efficient as those containing this ingredient, and of course under 

 these conditions the variation in the amount of potash was without 

 influence. Such a result was a surprise, and emphasizes the need 

 of further inquiry into the use of commercial plant-food. 



