FLUCTUATIONS OF YIELD 



37 



first eighteen years, yet the crop has been practically constant 

 during the last thirty years. The fluctuations during this period 



eooolb 



Plot 2. 



Plot 7. 



1844-51. 1852-61. 1862-71. 1872-81. 1882-91. 1892-1901 1902-1911 



FIG. 2. Broadbalk Wheat. Total Produce. 



are in the main due to season, and correspond very closely with 

 those of the completely manured Plots 6 and 7. For example, 

 there was a considerable drop during the decade 1872-81, a 

 period of notoriously bad seasons ; then followed a considerable 

 recovery in the next decade, which has been maintained for 

 the last twenty years. But all the evidence seems to point to 

 the fact that this plot, which has been without manure of 

 any description since 1839, has reached a stationary con- 

 dition, and that the average crop of twelve and a half bushels 

 for the last fifty years will in future diminish very slowly, if at 



