IV.] 



WATER EVAPORATED BY CROPS 



109 



inches of fallow and of adjoining land carrying a barley 

 crop — 



The total difference between the cropped and un- 

 cropped land down to the depth of 54 inches, amounted 

 to more than 900 tons of water per acre, or 9 inches 

 of rain, which is quite half as much again as would 

 be accounted for by the crop on the assumption that 

 only two tons or so of dry matter had been grown at 

 the date of sampling. 



Another example of the withdrawal of water from 

 the soil by the crop is seen in the proportions of water 

 in the soil of certain of the permanent grass plots at 

 Rothamsted, taken in July of the same year, 1870 — 



