INFLUENCE OF A CROP ON EVAPORATION 123 



TABLE XXIII 



AVERAGE EE8ULTS DURING FOUR YEARS OF THE 

 GENEVA (N.Y.) DRAIN-GAUGES 



In 1883 the evaporation from the turf reached 23-6 inches, 

 out of a rainfall of twenty-four inches. The smallest evapora- 

 tion in this experiment is from the cultivated soil, the surface 

 of which was maintained in a loose condition, thus affording 

 another illustration of the success of this plan for preserving 

 soil water. 



An additional illustration of the evaporating power of turf 

 is furnished by the series of daily determinations of water in 

 various soils conducted by the Agricultural Department of 

 the United States in 1895 (Soils, Bulletin 2, 8). Towards 

 the end of June the amount of water in the surface foot of 

 a blue grass pasture varied between 9 and 10 per cent., while 

 in similar soil with the sod removed it amounted to 19-20 

 per cent. 



It follows from what has now been said, that when a soil 

 is treated as a bare fallow, and left for a whole season without 

 a crop, being submitted during that time to frequent ploughing, 

 it is (notwithstanding its free exposure to sun and wind) in 



1 The total drainage from these gauges for 1886 is apparently wrongly 

 stated on p. 348 of the New York Fifth Report. The figures for that year which 

 are included above have been obtained by summing the monthly items 

 on p. 347. 



