RANGE PRESERVATION AND EROSION CONTROL. 



21 



counted for by the more luxuriant growth of the individual plants 

 on the noneroded soil regardless of the smaller amount of water re- 

 quired for the production of a unit of dry matter. 



In the case of native bromegrass and wheat the same behavior 

 holds as to vegetative growth and other facts as in the case of the 

 peas. Hence 2.4 and 2.1 times as many leaves of bromegrass and 

 wheat, respectively, were produced on the noneroded as on the 

 eroded soil; the leaf length, dry matter, and water used per plant 











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Peas Bromg Wneat Wheat Aeao's 



Water requirements per unit cfrjr weight 

 gaa Eroded soil 

 vazzzz Non-erod&d soil 

 — • Per cent difference 



Fig. 4. — Relative water requirements per unit dry weight for peas, native bromegrass, 

 and wheat grown in eroded and in noneroded soils of the same type. 



were greater on the noneroded soil by 0.8 and 1.3, 1.1 and 1.2, 0.7 

 and 0.5 for native bromegrass and wheat, respectively. And here, 

 again, the" water requirement per pound of dry. weight was greater 

 on the eroded soil by 20.6 per cent and 37.6 per cent for the native 

 bromegrass and wheat, respectively. 



Erosion is detrimental to plant growth chiefly because it brings 

 about the two following conditions of soil impoverishment: (1) 

 Lack of adequate soil moisture for the full development and seed 



