DRAINAGE AND SOIL STRUCTURE 



241 



bad physical condition, when first drained. Drainage 

 brings to bear upon the soil all those natural agencies 

 which promote the granular arrangement. In turn, 

 the granular structure, particularly in fine-textured 



Fig. 77. Section of a 20-year-old tile drain in heavy clay soil. Note the 

 more open structure above the drain. 



soil, affects the movement and capillary retention of 

 water, the circulation of air, the growth of organisms, 

 the temperature of the soil, and other conditions depend- 

 ent on these, in a manner highly beneficial to the crops 

 generally grown. 



112. Increases the available water. 



-Drainage in- 



