BULLETIN 318 THE EFFECTS OF ALKALI ON CITRI'S TREES 311 



It is not necessary to discuss the amounts of, and variations among, 

 the individual constituents of these waters. Casual observation of 

 the analyses will suffice to show that there is a wide range of difference 

 in the content of total dissolved materials and that a number of the 

 individual constituents occur in certain samples in relatively large 

 amounts. The most significant differences in these waters probably 

 lie in the chlorine and sodium. The unusually high nitrate content 

 of sample No. 119 is a matter of special interest. Where such water 

 is used for irrigation, it is highly improbable that nitrogenous ferti- 

 lizers will be needed. 



The variations found among samples that contain relatively large 

 amounts of salts, such, for example, as Nos. 642 and 643, are probably 

 of little practical significance. On the other hand, samples Nos. 103 

 and 105 contain still greater amounts of salts, especially so in the 

 case of the latter. Sample No. 150 is of intermediate composition and 

 represents a type of water that is being used at present on several 

 thousand acres of citrus in California. As will be pointed out later, 

 the use of this water on a lemon grove for a period of approximately 

 twenty years, produced definite injury. 



The numbers of pounds of a given constituent that will be added 

 to the soil by an irrigation water may be readily calculated from the 

 analysis. For example : an acre foot of water, No. 119, which contains 

 1479 parts per million soluble solids, will supply the soil 3993 pounds 

 of solids, while an acre foot of No. 84, containing 222 parts per million, 

 will add only 599 pounds. In view of the fact that the amounts of 

 water applied varies widely in different localities and in different 

 years in a given grove, it is not possible to state the exact amounts 

 of salts that have been added to the soil in a given case. It is only 

 possible at present to make qualitative comparisons among the groves. 

 It is evident, however, that large amounts of alkali must necessarily 

 have been added to the soil where such water as Nos. 119, 642 and 643 

 have been applied. Still greater amounts must have been added in 

 a given period with Nos. 103 and 105, while with No. 150, the rate of 

 salt addition has been considerably less. 



During the past eight years, several hundred acres of orange 

 orchards located near Riverside, which were previously irrigated with 

 suitable water, have been irrigated with saline water similar to samples 

 Nos. 119, 642 and 643. Other groves adjacent 1o these have been 

 irrigated from the beginning W i1h comparatively pure water (No. 

 !4). So far as can now be determined, the soil in this immediate 

 locality was reasonably uniform and free from alkali previous to 

 planting the orchards. The soil is of a sandy loam character, reason- 



