A NEW METHOD TO ESTIMATE TOTAL DISSOLVED SALTS IN SOIL SATURATUION EXTRACTS FROM ELECTERICAL CONDUCTIVITY UNDER EGYPTIAN CONDITIONS

                Fifty two soil samples with different quantities and qualities of salt were taken from different places in Egypt to present the most soil types. A saturation extract from each sample was prepared and its electrical conductivity (EC) and total dissolved salts (S) were determined. Both EC and S values ranged from 0.74 to 185 dSm^-1 and from 0.44 to 309 g dm^-3, respectively.
                   The relationship between S and EC was not linear. When the saturation extracts were diluted with progressively large quantities of distilled water [1(saturation extract):10, 25, 50, 100, 250, 500, 1000 (distilled water)] and their electrical conductivity were calculated (EC_e) with the equation: EC_e =(EC_d –EC_w)F, where EC_d and EC_w were the conductivity of the diluted extract and the distilled water, respectively, and F was the dilution factor, the relationship between S and EC_e tended to be linear.
                    The highest linear correlation coefficient relating S (mg dm^-3) and EC_e (dS m^-1) was reached when EC_e values were calculated for dilution with an electrical conductivity (EC_d) between 0.1 and 0.5 dSm^-1 (EC_e^*). The regression equation was S=425 EC_e^* with R²=0.989. This relationship can be used in all saturation extracts, regardless of the concentration and type of ions present.