CROPS AND SOIL IMPROVEMENT 



the rule that plant-roots should not be pruned by 

 deep cultivation is found in the case of a close soil 

 in a wet season. The plants extend their roots 

 only in the soil at the surface because the ground 

 is soaked with water nearly all the time. They 

 cannot form far enough below the surface to with- 

 stand a drouth that may follow the wet weather. 

 Good tillage in such a case demands the pruning 

 of the roots and the airing of the soil when the 

 ground is dry enough to permit such stirring, and 

 the plants then extend their roots in the lower 

 soil where they rightly belong. Judgment is re- 

 quired to decide when such tillage is desirable, 

 but judgment is needed all the time in farming. 

 When a continued period of wet weather affects 

 the position of the plant-roots, it rarely is advis- 

 able not to risk deeper tillage than is given in a 

 normal season. Underdrainage helps to prevent 

 such ill-effect of continued rains in the early part 

 of a plant's life-time. 



Elimination of Competition. Weeds pump 

 the water out of the soil, use up available plant- 

 food, and compete for the sunlight. Tillage is 

 given for several reasons, and one is the destruction 

 of weeds. A weeder which stirs the soil only an 

 inch or two deep is an excellent destroyer of weeds 



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