74 The Bulletin 



(4) That potash added to nitrogen and phosphoric acid resulted in 

 a small increase in yield and without profit; and 



(5) That the use of lime alone resulted practically in no profit per 

 acre, but when used with nitrogen, phosphoric acid and potash there 

 was a somewhat better showing made. 



Effect of Varying Quantities of Nitrogen. — These experiments were 

 arranged to test the effect on the yield of corn and stover of varying 

 quantities of nitrogen, leaving the phosphoric acid and potash con- 

 stant. 



On one plat the nitrogen was reduced to one-half the normal quan- 

 tity, making the application 41/2 pounds of nitrogen per acre, or practi- 

 cally 2.4 per cent in the actual amount of the fertilizer mixture used. 

 On two of the plats it was increased by two and three times the normal 

 quantity (9 pounds per acre) making the application 18 and 27 pounds 

 per acre respectively, or on the four plats 41/2, 9, 18, and 27 pounds of 

 nitrogen per acre. 



The average results for three years in Field A showed the largest 

 profit to have come from the application containing three times the nor- 

 mal quantity of nitrogen per acre, or 27 pounds of nitrogen, the average 

 yield being 24.3 bushels corn per acre, and the profit $4.65 over cost of 

 fertilizer on the basis of corn alone or $9.60 on the basis of com and 

 stover. For five years in Field B the largest yields and profit were 

 too from the application containing three times the normal quantity of 

 nitrogen, the average yield of corn being 24.5 bushels per acre, and the 

 profit $4.97 over cost of fertilizer, on the basis of corn alone, or $10.13 

 on the basis of corn and stover. Averaging the results of both fields, 

 the gain per acre from the use of the N3 P K application was $4.81 on 

 the basis of com alone and $9.87 when both corn and stpver are con- 

 sidered. On an average as will be seen from the results in Table VII 

 the yields and profits per acre increased as the amount of the nitrogen 

 in the mixture increased. 



Effect of Varying Quantities of Phosphoric Acid. — This part of the 

 experiineiits were planned to show the effect on the yields of corn and 

 stover of varying quantities of phosphoric acid, the nitrogen and 

 potash remaining the same. On one plat one-half the normal quantity 

 of phosphoric acid was applied or an amount represented by 65.5 

 pounds of 16 per cent acid phosphate and equivalent to 6.7 per cent 

 phosphoric acid in the fertilizer mixture. On two plats were applied 

 two and three times the nomial quantities of phosphoric acid repre- 

 sented by 263 and 394 pounds of 16 per cent acid phosphate respectively, 

 or 42 and 63 pounds of phosphoric acid per acre. The results in all 

 the fields show increased yields and profits from all the different quanti- 

 ties of phosphoric acid. The largest increase in grain in yield on 

 Field A was from the use of three times normal phosphoric acid with 

 nitrogen and potash, while in Field B it was from the use of three times 

 normal phosphoric acid. On an average of the results of both fields, 

 there was practically no difference in the profit per acre above cost of 

 fertilizer from the two and the three r»hosphoric acid applications, when 

 the quantities of nitrogen and potash remained the same in the mixtures. 



Effect of Different Quantities of Potash. — These experiments were 

 arranged to show the effect on the yield of corn and stover of varying 



