The Bulletin 97 



Taking the results as a whole for both hay and peas, the most profit- 

 able application of phosphoric acid is 300 and 450 pounds of 16 per 

 cent acid phosphate when the nitrogen and potash applications are con- 

 stant at 3 and 12 pounds per acre respectively. By increasing the ap- 

 plication of acid phosphate from 75 to 300 pounds the profit per acre, 

 for hay and peas above cost of fertilizer, was increased 3.6 times. 



Effect of Varying Quantities of Potash. — This portion of the experi- 

 ments was planned to shoAV the effect upon the yield of hay of varying 

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

 stant. On one plat one-half the normal quantity of . potash was ap- 

 plied, or about 3.0 per cent in the actual fertilizer mixture used, while 

 on two other plats tAvo and three times the normal quantities were given, 

 or 24 and 36 pounds per acre, the percentage of potash in the highest 

 application being somewhat in excess of 10 per cent. 



EFFECT ON YIELD OF HAY. 



While there are some variations in the yield, the results show de- 

 creased rather than increased yields from applications of potash, and on 

 none of the plats in either of the fields Avere the profits from the appli- 

 cations of potash in any quantity as great as from phosphoric acid 

 alone. 



On the whole, these tests shov/ that potash used beyond 12 pounds 

 per acre has decreased yields and profits. 



EFFECT ON YIELD OF PEAS. 



In the four years experiments on plats in Field C the increase in 

 the yields of peas was very small and not sufficient to overcome the cost 

 of fertilizer, which was used, in three out of four cases, at a loss. In 

 one year's experiments on the plats in Field A the fertilizer application 

 produced decided increase in pea yields, but the profits in only two cases 

 were greater than from phosphoric acid alone and in only one from 

 phosphoric acid and potash, and the increases in these cases were small. 



Taking them altogether, the results show that increases in quantities 

 of potash have not profitably added to the yields of peas. 



Effect of Varying Quantities of Fertilizer. — These experiments show 

 the effect of increasing and decreasing the normal (N P K equals 300 

 pounds of a fertilizer mixture containing 8 per cent phosphoric acid, 4 

 per cent of potash, and 1 per cent nitrogen) fertilizer application on 

 the yields of hay and peas. The applications were at the rate of 150 

 pounds per acre, !/•> (IST P K) ; 300 pounds per acre, IST P K; 450 

 pounds per acre 1^2 (^ P K) ; 600 pounds per acre, 2 (IST P K) ; and 

 900 pounds per acre, 3 (N P K). 



EFFECT ON YIELD OF HAY. 



The results show an increased yield of hay for the increased appli- 

 cations on the plats in Field A, the greatest average profit coming from 

 the application of 600 pounds of fertilizer per acre; while on plats in 

 Field C 300 pounds per acre gave the most profitable yields. 



