Relationships of Electrical Conductivity With Total Dissolved Salts and Cation Concentration of Sulfate-Dominant Soil Extracts

Simple equations for accurate estimation of total dissolved salts (TDS) and cation concentration (CΣ) from electrical conductivity (EC) measurements (ranging from 0 to 16 mS/cm) were developed for sulfate-rich soils in southern Alberta. Soil extracts were obtained by the saturation extract method from 879 samples. From 260 of these samples, the 1:10 extraction method was also used. Electrical conductivity and TDS in the solution (by summation of the ions and/or by evaporation) were determined. Several regression equations were fitted. The following equation is recommended for estimating TDS (in mg/L):[Formula: see text]For estimating the cation concentration (CΣ in meq/L), the equation[Formula: see text]is recommended. Total soluble salts determined by summation of ions was about 16% less than that by the evaporation method. The amount of salts extracted from the soil was greater with 1:10 extraction than with the saturation extract method, but considerable discrepancy was found between the two extraction methods.