A Study of the Relationship between Ionic Strength and Electrical Conductivity in Salt Affected Soils

To find the nutritional condition of plants as related to the tatus of soil nutrients, also for an evaluation of soil solution toxicity and nutrition of plants in salt affected soils, it is preferred to study the activity of these elements rather than their concentrations. To calculate the ionic strength of a solution the concentrations of all cations and anions are needed which is very time consuming to be determined. This research was carred out to investigate the relationship between ionic strength and ECe in salt-sodic soils in Hoze-e-Soltan, Qom. In 40 soil samples, such physical and chemical properties as texture, pH, saturation moisture, gyps, lime, cation and anions in soil solution (Na, K, Ca, Mg, Cl, Co3, HCo3, So4) were assessed. Following a determination of ionic strengths, equation was employed for making calculations. Results showed that the values of ECe and pH in studied soil samples varied from 12.90 to 146.40 ds/m and 8.20 to 8.90, respectively. Relationship between ECe and ionic strength was exponential and 92% of IS variations being resulted from EC. Also, ther eexists a significant linear agreement (r2=0.92) between IS (using Griffin-Jurinak model) and IS, using the concentration of the cations and anions measured in soil samples.