1910.] PUBLIC DOCUMENT — No. 31. 41 



used in quantities to furnish equal actual ])(>tasli per acre 

 annually, the crop the past year was hay, mixed timothy, red 

 top and clovers. The average yield of the no-potash plots was 

 at the following rates per acre : — 



Pounds, 



Hay, 5,744 



Rowen, 680 



The average yield of all the potash plots, 35 in number, was 

 at the following rates per acre : — 



Pounds. 



Hay, 6,412.6 



Rowen, 1,555.4 



It will be noticed that the increase in the yield of hay was 

 not very large, and that the yield without the potash was for 

 both crops slightly in excess of 3 tons per acre. The rowen 

 crop on the potash plots is much greater than on the no-potash 

 plots because of the larger proportion of clover. The most 

 striking result of the experiments, indeed, is the comparative 

 failure of clover on the plots to which no potash was applied, 

 and its great inferiority on the five plots to which kainit is 

 annually applied. On these plots, and especially on the plots 

 to which the kainit is applied, the yield of timothy was re- 

 markably heavy, the proportion of this grass being much 

 greater than on plots to which the other potash salts are applied. 



V. In the field where ten of the leading materials which 

 may be used as sources of phosphoric acid have been under com- 

 parison since 1897, the crop during the past year was soy 

 beans. The phosphates used in this experiment are applied in 

 connection with equal and liberal quantities of nitrogen and 

 potash in available forms, at such rates as will furnish equal 

 actual phosphoric acid per acre. The average yield of the three 

 no-phosphate plots was at the rate of 6,668 pounds, or 27.8 

 bushels per acre. The average yield on the ten phosphatic 

 fertilizers was at the rate of 1,835.2 pounds, or 30.6 bushels. 

 The average increase on the phosphate plots as compared with 

 the no-phosphate was at the rate of 167.2 pounds per acre. 

 The highest increase, at the rate of 296 pounds per acre, was 

 produced on the steamed bone meal. This increase is at the 



