94 CALIFORNIA VEGETABLES. 



the distribution of irrigation water, they are a delusion 

 and a snare if carried into summer work. The very re- 

 lease of water which fits them for winter use unfits them 

 for the dry summer. Level culture is the broad basis 

 upon which summer conservation of moisture rests. The 

 plant root should neither be lifted into the air nor should 

 the soil be opened so that the air is allowed to freely de- 

 scend 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 bot- 

 tom 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, however, heroic treatments and 

 if employed late in the rainy season are apt to give the 

 lower layers of the soil opportunity to dry beyond desir- 

 able moisture retention. If only a slight surface drying 

 is necessary a narrow-toothed harrow or cutting discs with 

 slight lateral pressure will accomplish it. 



