DRYING LAND BY TILLAGE 75 



should neither be lifted into the air nor should the soil be opened 

 so that the air is allowed to freely descend to the plant roots. Soil 

 and air assume proper relations when the culture is flat and fine 

 and sufficiently deep. 



Tillage to Release Excessive Moisture. The occasion for this 

 course, except in stated winter practice already described, rarely 

 occurs in California except on lowlands in regions of ample rainfall, 

 though sometimes a large precipitation in a short time may too 

 long delay planting until the surplus is disposed of. Plowing with 

 rather a long slope of moldboard, which turns furrows without 

 crushing and laps them well, leaves air spaces at the bottom of the 

 furrow-slice and aids greatly in drying the soil. Sub-soiling also 

 allows water to percolate and air to enter freely. These are, how- 

 ever, heroic treatments and if employed late in the rainy season are 

 apt to give the lower layers of the soil opportunity to dry beyond 

 desirable moisture retention. If only a slight surface drying is 

 necessary a narrow-toothed harrow or cutting discs with slight 

 lateral pressure will accomplish it. 



