Envir:l8 



10 20 

 Soil Moisture 



30 

 % dry wt. 



40 



50 



100 

 o 



(0 



to 80 

 ^ 60 



40 . 



20 



5 4 

 Soil Moisture 



Log cm. HpO Tension 



Figure 7 Itoisture content and CO2 evolution in 53 days 

 from Monona sil. loam. (Hallam Ph D. Thesis, 

 Iowa State College. 1952.) 



