EVAPORATION FROM BARE SOIL 



109 



evaporation being reached in June and July, namely 3-14 and 

 3-44 inches. After July the evaporation again diminishes 

 till the winter minimum is reached. In five months of the 

 year the evaporation exceeds the rainfall, but in the whole 

 year it is less than the rainfall by 5 inches. 



The rate of evaporation from a perfectly saturated soil 

 destitute of vegetation, is somewhat greater than from a 

 water-surface, the rough soil exposing a larger area of surface 

 than the level surface of the water. The average evapora- 

 tion from the bare loam in the Rothamsted drain-gauges 

 (Table XXII) during six winter months (4-8-5-2 inches) is 

 quite similar to that from a water-surface (4-8 inches), but in 

 the six summer months the evaporation from the Rothamsted 

 loam (11-1-11-5 inches) is distinctly less than that from water 

 (15-9 inches), as the soil is at this season seldom saturated. 



The annual evaporation from the Rothamsted bare loam is 

 singularly unaffected by the amount of the rainfall. The 

 following table shows the results obtained during the first 



TABLE XIX 



EVAPORATION AND PERCOLATION FROM BARE LOAM, ROTHAMSTED, 

 DURING NINE YEARS 



