An experiment was carried out in permeameters provided with vertical column and constant hydraulic head in order to evaluate sodification risks of soils with contrasting characteristics and treated with solutions of different electrical conductivities (EC) and sodium adsorption ratios (SAR). The treatments consisted of nine soils and eighteen percolating solutions with three EC values (175, 500 and 1,500 mS cm-1) and six SAR values (0 to 30 for sandy soils, 0 to 25 for medium textured soils and 0 to 15 for clay textured soils). Initially, the adjustment of the Na:Ca ratio on the cation exchange complex of the soils was performed using solutions with concentration of 50 mmol c L-1. Later on leaching with solutions of different EC but same SAR was maintained to reach steady state flow, when the permeameters were dismantled and the soil samples removed for chemical analysis. Exchangeable sodium and cation exchange capacity were determined to calculate exchangeable sodium ratio (ESR) and exchangeable sodium percentage (ESP). Equations were adjusted between either ESR or ESP with EC and SAR of the percolating solution, the increment of EC and SAR elevated the soil ESR and the ESP. It may be concluded that the correct assessment of the sodification hazard has to take into consideration the soil properties and the water quality.
electrical conductivity; sodium adsorption ratio; exchangeable sodium
