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C) o ~.. CO . -.J c;p approximately 2 mmhc~m greater saturation extracts than those growing in the chloride treated s0ils at the Salinity Lab. Similar findings are reported by Shoshin (1955) as cited by Stroganov (1962) and Doneen (1963). Declination yield curves were based upon the CiJllfornia Committee of Consultants' Report and inter[.lreted with a 2 mmho/cm increase when comparing soil saturation extracts from projected values. PROCEDURE The base point of the soil extract conductivities was determined from mean values of soi I extracts taken from 33 locations twice yearly over a 10- year period on four 5011 classifications on the Imperial Valley Field Station. The 95% confidence intervals of these samples are presented in table 3. A similar interval was determined for the irrigation water conductivity. The ratios of the mean soil saturation extracts to the mean conductivity of the Irrigation water is shown in table 4. The median of each ratio was utilized to project the soil salinity which developed with tne current best practice on that soil, as defined in Guidelines Imperial County Crops Circular 104 (1973) . In view of the statement, "At present our ability to predict changes in soli solution concentration during infiltration and drainage has not been ascertained. Theoretical and experimentai analysis involving nonsteady flow conditions are both meager and incomplete.1I Nielsen (1972). This study wi II assume that the ratio between the conductivity of soi I saturation extl-acts and the conductivity of the irrigation water wi 11 remain constant. Consultation with Robert Zimmerman, Soil Conservation Service, produced the acreages of the major soli classifications in the Imperial Valley. He also Indicated the general distribution of crops on each soil class, table 5. Mean crop yields and acreage were obtained from 1965 to 1972 from the Annual Crop Reports, Agricultul'al Commissioner, Imperial County Courthouse. These are shown in table 6. Utilizing the Fc regression as a function of TDS from table I and the median ratios from table 4, table 7 was constructed indicating a projected median conductivity of a saturated soil extract at different TON levels. The irrigation management influence was defined as a function of tho zone from which water was e;<tracted from the soil. When intervals were Ions enough to require 13.3 cm application (16 irrigations per year), the sa1inity 17