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JOHN ERNST WEAVER 



1913, well illustrate this process. On October 15 the north-side 

 soil had a water content of 17.4*% and 23% at 6 inches and 12 

 inches respectively, while that on the south slope had only 11% 

 and 12% at the two depths. The graphs show a general in- 

 crease of water content (except for a trough in late November) 



Fig. 1. Graphs showing the march of soil water to a depth of 10 inches from 

 April 25 to September 25, L913, (heavy lines), and from May 22 to August 10, 1914, 

 on a northeast slope (solid lines), and a southwest slope, respectively. 



and on January 1 the water content had increased to 31% and 

 41% respectively, on the north slope, and 28% and 28% on the 

 south slope. 



It is apparent from these data that prairie plants must obtain 

 their water from greater depths than 10 inches, at least during 

 the dry summers. In fact, some of these plants penetrate to a 



