Nature-Study Agriculture 



Why weeds 

 larmful 



W. T. Stilling 



FIG. 33. The earth that was allowed to pack and crust over lost water 

 (became lighter) more rapidly than the earth that was stirred. 



Cultivation, therefore, furnishes them with the air that 

 they need. 



(5) // destroys weeds. Weeds live on exactly the same 

 ^^ ^ plant-food material that the crops require, and 

 some use more food and water than do crop plants. 

 Hence, every weed is a crop robber ; and, as some weeds 

 are hardier and more prolific than the crop plants, they 

 may even crowd out a crop and take its place. Cultiva- 

 tion at the right time destroys the weeds and greatly 

 benefits a crop (Figs. 35, 86, and 87). 



The Egyptians used a crude wooden plow tipped with 

 iron and drawn by men or oxen, to scratch up the surface 

 of their fields (Fig. 36). With such methods a farmer 

 could till but little land, and that little not very well. 

 The plowshare made entirely of metal was not invented 



