BuEEAu OF Ageioxtltuee. 169 



At Mayfield the average gain for wheat was 6.6 

 bushels per acre for acid phosphate, while for potash 

 alone and in combination with limestone and acid phos- 

 phate, it was ^.8 bushels. But comparing the plot treated 

 with acid phosphate, limestone and potash with plots 

 treated with acid phosphate and limestone, there is no 

 gain for potash, the yield being 27.3 bushels per acre in 

 each case. 



On the Berea (Madison county) experiment field last 

 year acid phosphate and limestone gave 45.7 bushels of 

 com per acre, while limestone, acid phosphate and potash 

 gave 46.4 bushels. The yields of soy bean hay on cor- 

 responding treatments were 3,650 pounds and 3,770 

 pounds per acre. The yield of com on untreated ground 

 was 27.8 bushels per acre, and of soy bean hay 2,845 

 pounds. 



On page 79 of Circular No. 144, of the Ohio Experi- 

 ment Station, Dr. Thome shows that as the average re- 

 sult of twenty years' experiments on the Wooster ex- 

 periment farm, $6.50 invested in potash returned $1.44 

 above its cost, while $2.60 invested in acid phosphate 

 paid its cost and a net profit of $13.92. On page 97 of 

 the same Circular he further shows that as the average 

 results of nineteen years' experiments on the Strongs- 

 ville experiment farm, $2.60 iuvested in acid phosphate 

 paid its cost and gave a net profit of $14.88, while $6.50 

 invested in potash returned $4.27 less than its cost. In 

 the above cases the gain is for phosphate used alone in 

 the rotation, while potash is used in addition to phos- 

 phate and nitrogen, giving the potash full opportunity 

 to show its effects. 



Dr. Hopkins, in the National Stockman and Farmer 

 of April 3, 1915, shows that in the Pennsylvania experi- 

 ments from 1885 to 1908, one dollar invested in potash 

 paid back 9 cents, while phosphate paid $3.44 per $1.00. 

 In this case also potash was applied in addition to phos- 

 phate and nitrogen. 



In commenting on the soil requirements for com. 

 Prof. "Williams, of the Ohio Experiment Station, says on 

 page 76, Bui. 282 : 



"Proper soil conditions for the corn crop will then include thor- 

 ough under-drainage, either natural or artificial; a crop rotation which 

 will adequately maintain the organic matter of the soil through the 



