Soil Moisture 



Average seasonal trends in the soil's moisture content at 20-, 50-, and 100-cm. 

 depths are shown in figures 11-13. These trends should be viewed with respect to 

 moisture stress for plants primarily. The 15-atm. moisture-tension level indicated on 

 each figure is considered the point at which moisture availability generally starts to 

 limit plant growth. The position of this level depends largely upon soil texture; 

 consequently, it often differs with soil depth. Monthly averages of soil moisture are 

 shown in table 12, 



Moisture levels at the 20- and 50-cm. depths were usually near maximum at the 

 beginning of the growing season, early in May. The moisture level at 100-cm. depth was 

 also near maximum on the northeast exposure. However, May and June rains were required 

 to replenish the moisture supply at the 100-cm. depth on the southwest exposure. The 

 snowpack on southwest exposures is typically shallower than that on the northeast 

 exposures; consequently, less moisture is available to recharge the soil mantle on the 

 southwest exposure. 



20 



