328 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



drainage water. In localities where the volume of the drainage water 

 resulting from such leaching constitutes any considerable portion of 

 the natural drainage water, the ground water may ultimately become 

 heavily charged with salts as a result. This is especially to be feared 

 where the ground water is rising or is already near the surface. In 

 view of these facts, the application of saline irrigation water should 

 be avoided, whenever possible. 



The experience of the growers near Corona, following the use of 

 water from Lake Elsinore, is of special interest at this time. Some 

 of the groves that were severely injured then, have since recovered 

 and have borne profitable crops of fruit, while others have not yet 

 fully recovered. In general, the most effective treatment was found 

 to consist of thorough tillage, plowing down manure and the applica- 

 tion of suitable irrigation water. 



If good water be applied freely it is probable that the harmful 

 concentrations of salts that have accumulated will be gradually leached 

 dow r n below the reach of the roots and the use of manure, coupled with 

 deep plowing, will gradually restore conditions favorable to growth. 

 As a means of further increasing the porosity of the soil, an applica- 

 tion of gypsum may also be desirable. In addition to its flocculating 

 effect, gypsum, and other calcium salts also, seem to ameliorate the 

 effects of toxic concentrations of alkali salts, and enable crops to 

 tolerate concentrations of alkali salts that are prohibitive of normal 

 growth in the absence of an abundance of calcium salts. 



"While somewhat apart from this investigation, it may be appro- 

 priate to state, that a limited study of the amounts of water available 

 to the citrus groves of California leads us to believe that the most 

 promising source from which a supply of really good water can be 

 secured in quantities sufficient to meet the demands of the constantly 

 expanding citrus industry, can be obtained only through concerted 

 effort directed towards the control of flood waters. By the use of 

 suitable check dams, reservoirs, reforestation, and such other devices 

 as will permit the storage of the mountain waters, either above ground 

 or within the water-bearing gravels, an adequate supply of suitable 

 water can probably be obtained. At any rate, the excellent water 

 that falls in the mountains of California, may be so conserved as 

 to augment materially the volume of water now being obtained from 

 them, and thereby make it possible to discontinue the use of at least 

 a portion of the saline water. 10 



i" Acknowledgment is due Mr. A. B. Cummins and Mr. S. M. Brown for 

 analytical assistance rendered in connection with this investigation. 



