216 THE PRINCIPLES OF SOIL MANAGEMENT 



The velocity of the wind next to the ground may be 

 checked by ridging the soil. It is doubtful if this prac- 

 tice conserves moisture, because more surface is exposed 

 over which evaporation may take place. On the other 

 hand, wide experience, as well as investigation, indicates 

 that for the conservation of water level culture is better 

 than ridged culture. This principle has led to the gradual 

 abandonment of the practice of "laying by" corn and 

 potatoes with a high ridge. In all regions of deficient 

 rainfall, the best practice prescribes level tillage and 

 a fine, dry mulch, both of which are attained by the 

 frequent use of shallow-running small-toothed culti- 

 vators. Many experiments have demonstrated the 

 larger crop yields to be obtained from this practice, 

 on the average. 



The removal of weeds has been mentioned as a means 

 of conserving moisture. The plants serve to expand 

 evaporating surface in the same way as ridged culture. 

 (See page 195.) 



99. Increasing the water capacity. Increasing the 

 water capacity of the soil may be effective in conserving 

 soil moisture by holding more of the water which falls. 

 The first aim should be to get the rainfall or irrigation 

 water into the soil. It is well known that after a long 

 dry period when the soil particularly a fine-textured 

 soil has become dry and hard, the first rainfall may 

 be largely lost by running away over the surface. Sudden 

 showers are almost entirely lost in this way, because 

 not only is the water repelled, but the small amount which 

 is absorbed is held so near the surface that it is quickly 

 lost. Gentle rains are usually much more effective 



