Modeling of exchangeable sodium ratio on the saline soil

Abstract

Background and Objective: Despite the expansion of salinity in arid and semiarid regions, the measurement of exchangeable cations concentrations such as exchangeable sodium ratio in saline soils remains difficult. Exchangeable sodium ratio (ESR) often measured by using the time-consuming laboratory tests. The correlation between ESR and sodium adsorption ratio (SAR) has documented in many studies. However, no studies have undertaken to model soil ESR in the Sarakhs Plain, Northeast Iran. The aim of this study was to evaluate a linear regression model between soluble and exchangeable cations in this area. Materials and Methods: In this study, 124 soil samples randomly taken from surface and subsurface the experimental site. The soil samples collected using a soil auger at 0-30 cm and 30-60 cm depth. Then the linear regression model was used for predicting soil (ESR) on saline soil. The soil ESR values measured in soil samples compared to the soil ESR values predicted using the soil ESR-SAR model. Results: The statistical results indicate that in surface soil (0-30 cm) and subsurface soil (30-60 cm), to predict soil ESR from soil SAR, the linear regression model ESR = 0.0182SAR-0.027 with (R2 = 0.92, p<0.001) and ESR = 0.0157SAR-0.020 with (R2 = 0.83, p<0.001) can be recommended, respectively. Conclusion: In conclusion, the soil ESR-SAR model recommended for the prediction of soil ESR to its significant importance reducing in time and field checking.