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PRINCIPLES OF FARM PRACTICE 



Besides depriving cultivated plants of water and other 

 requirements for their growth, the presence of weeds in hay 

 and forage crops reduces their value for feeding purposes. 



Weeds are also responsible for the continuance of many 



Effect of weeds on crop production. Ground plowed, seed 

 bed prepared, weeds allowed to grow. Yield, 8 bushels. (Il- 

 linois Agricultural Experiment Station.) 



plant diseases, such as rusts, by acting as host for the fungus 

 until the cultivated plants appear. Weeds bear a similar 

 relation to insects. 



Why weeds are difficult to control. Weeds are extremely 

 successful in competing with other plants because of several 

 characteristics. They are able to withstand adverse con- 



