130 MASS. EXPERIMENT STATION BULLETIN 212. 



Table 1. — The Corn Crops. 



Grain (Average Yields per Acre, Bushels). 



1 These plots were discontinued in 1911. 



These results are presented in graphic form in Fig. 1, arranged to show 

 the total yields of grain and stover, and likewise the comparative yields 

 in the two five-year periods. It wdll be noted that the yield of grain de- 

 creased very materially and significantly in the second five-j^ear period. 

 In all of those plots to which potash treatment was apphed, the yield of 

 stover did not decrease in like measure. On the other hand, where potash 

 was not applied, the decrease in the yield of stover was somewhat similar 

 in its significance to the decrease in grain. In all cases, the number of 

 pounds of stover produced per bushel of grain was larger in the second 

 period than in the first, and very materially so in the no-potash treat- 

 ments. 



The First Ten Corn Crops. 



The Check Plots. — The significance of the results and their interpre- 

 tations may best be judged on the basis of the yields on the check plots. 

 There were four such plots, numbered respectively, 3, 6, 9 and 12. The 

 following table shows the yields of corn divided into two five-year periods. 

 Under the system of farming followed, the yielding power of the untreated 

 soil was very low. The acre yields in the second period were practically 

 zero. The check plots were, however, fairly uniform in production. 



