PRACTICE XXII (Continued) 



What bearing does this practice have on prevention of de- 

 structive erosion ? 



References. 



" Soils," Lyon and Fippin, pp. 129-130 and 153. 



"The Soil," Hall, pp. 117-118. 



Circular No. 119, Illinois Agricultural Experiment Station. 







95% 



90% 



80% 



60% 



Soil 



Organic 

 Matter 5% 



Organic 

 Matter 10% 



Organic 

 Matter 20% 



"" /o 



Organic 

 Matter 40% 



Time required for soil to become moist 

 on surface 











- 



Weight of tube 













Weight of tube and air-dry soil . . 













Weight of air-dry soil 













Weight of tube and wet soil . . . 













Weight of capillary water retained . 













Per cent of hygroscopic moisture — 

 average for mixture . . . . . 













Weight of water-free soil ... * 













Per cent of capillary water retained . 













Apparent specific gravity — average 

 for mixture 













Weight of a cubic foot of soil . ■ .' . 













Pounds water retained per cubic. foot 













Acre inches of water 













Grams or unit of water retained by 

 1 g. or unit of organic matter . . 













47 



