iqh] 



FULLER— EVAPORATION AND SOIL MOISTURE 



22 







The ravine of the oak -hickory forest, with its abundance of 

 humus, gave wilting coefficients of 16.3 per cent and 12.2 per cent 



Fig. 23.— Graphs showing the range of soil moisture in the ravine of the oak- 

 hickory forest for 1911; the heavy line at 7.5 cm. and the light line at 25 cm. depth; 

 wilting coefficient represented by broken lines. 



respectively for the soil at depths of 7 . 5 cm. and 25 cm. The graphs 

 (fig. 23) show the presence of a constant' and abundant supply of 

 growth-water throughout the season. This would quite agree with 



