IV.] 



HUMUS IN WET AND DRY SEASONS 



119 



to June, was 13 inches in 1879 an ^ only 2-9 inches 

 in 1893. 



Wheat. Yield in Bushels of Grain. 



The average yield on the dunged plot is about 3 

 bushels more than on plot 7, but in the dry year its 

 superiority amounted to 14 bushels, whereas in the 

 very wet year the two plots sank to the same low level. 

 In a bad season the bacterial changes which render the 

 plant food in dung available for the crop go on very 

 slowly. 



