2 If) CALIFORNIA FRUITS: HOW TO GROW THEM 



SUB-IRRIGATION IN CALIFORNIA 



The word "sub-irrigated" is freely used in California to describe 

 land which is moistened below by underflow or seepage from 

 streams or springs, or from open irrigation ditches, traversing 

 higher levels. This land is sub-irrigated, it is true, but there is 

 no system about it, except the natural distribution of water, which 

 is to seek its level. Some of our most productive lands are of this 

 character, and where the soil and subsoil are fitted to the move- 

 ment of this living water, and not apt to retain, it up to the point 

 of saturation, most satisfactory growth of deep-rooting field crops 

 and of trees and vines are secured. But this is not sub-irrigation 

 in the ordinary signification of the term. 



Several systems of sub-irrigation by subterranean pipes have 

 been devised by California inventors, but none have passed beyond 

 the experimental stage, and no considerable acreage has been con- 

 tinually operated. 



DRAINAGE IN CALIFORNIA 



There was for a long time a very erroneous popular generaliza- 

 tion that California soils do not need drainage ; that in a dry state 

 the aim should be to retain the moisture, not to part with it. It 

 is, of course, true that we have vast areas of naturally well-drained 

 soil, upon which any money spent for drainage would be in great 

 part thrown away, but we have, also, both in the valley and on the 

 hillsides, localities where, by peculiar character and conformation 

 of the subsoil, water is held in the soil until evaporated from the 

 surface, and the result is a boggy, miry condition, which prevents 

 proper winter cultivation, and at the same time injures the roots 

 of the trees or vines. This defective cultivation, added to the 

 puddling effect of standing water, makes the soil dry out completely 

 under the fervid sun of summer, and the result is that the wettest 

 soil of the winter is the driest in the summer, and plants which 

 are injured by soaking in winter suffer again from lack of moisture 

 and sustenance in summer. Thus it is a fact, clearly proven by 

 observation and experience, that thorough under-drainage removes 

 surplus water in winter, and ministers to the retention of moisture 

 in summer. More than this, a soil puddled by standing water can 

 not present its contents in available form for plant nutrition, and 

 besides, it loses the fertilizing effects of atmospheric currents, which 

 pass through an open, well-dried soil. Wet land is cold and late 

 in spring, and hot as a baked brick under the summer sun; it is 

 no fiction of the imagination to say that well-drained land is 

 warm in winter and cool in summer that is, cool to a degree which 

 favors quick and free root growth, and cool enough to escape the 

 parching effect of deeply baked soil. 





