226 Physics of the Soil. 



young weeds before they are well rooted ; but this is not an 

 effective tool when weeds have a start nor where the soil is 

 at all hard or heavy. 



FIG. 63. Weeder. 



276. Cultivation After the Harrowing Stage When 



plants have become too large to permit the harrow or 

 weeder to be used to advantage a tool with broader teeth is 

 needed. Cultivation or intertillage should begin as soon 

 as the first fresh weeds start and great pains should be 

 taken to work so close to the row that all the soil is either 

 stirred or covered with a thin layer of fresh soil. Few 

 realize how close it is possible to work to a row without 

 either covering the plants or seriously injuring the roots, 

 until they have learned to do it. It is early and frequent 

 harrowing and careful close first cultivation that insures 

 scrupulously clean fields and the largest yields the season's 

 rainfall will permit. 



277. Cultivators for Intertillage. When harrowing has 

 been properly practiced intertillage may begin with a tool 

 whose teeth are about 2 inches wide and there should be 

 enough of them to thoroughly stir the whole soil surface to 

 a depth of two anc[ one-half to three inches. Fig. 64 shows 

 a good set of teeth for soils not too heavy, while Fig. 65 

 shows a tool which should not as a rule find a place in well 

 cared for fields, for the teeth are too wide and too few for 

 good general work. They are wasteful of moisture, waste- 

 ful of fertility and liable to do too much root pruning. 



