EFFICIENCY OF Ca^2+ APPLICATION FOR THE RECLAMATION OF SALINESODIC SOILS WITH DIFFERENT SOIL TEXTURES

A lysimeter experiment was conducted to evaluate the effectiveness of different Ca^2+ concentrations in canal water for the reclamation of saline-sodic soils with a range of textures. Calcium Sulphate (CaSO4.2H2O) was added to canal water at Ca^2+ concentrations of 4 (Ca4), 8 (Ca8) and 12 (Ca12) mmolc L^-1. Four pore volumes (PV) of irrigation were applied in four equal splits. During each leaching cycle, leachates were collected and analyzed for EC and soluble ions (Na^+, K^+ and Ca^2+). The maximum volume of leachates was obtained in the fourth leaching cycle at the highest Ca concentration (Ca12). The leaching volume was affected significantly by soil texture and was the highest for the sandy clay loam (SCL) followed by sandy loam (SL) and clay loam (CL). The treatments had an insignificant effect on the removal of salts (EC) but the SAR of leachates was significantly affected by the treatments. The results clearly showed that increasing Ca^2+ concentration in leaching solution decreased ECe of the soil but there were no differences among Ca^2+ treatments for removal of Na^+ and it was significantly higher in first leachate and gradually decreased in subsequent. The concentration of Ca^2+ in leachates followed the order of Ca12 Ca8 Ca4 Ca0 and was also affected by soil texture in the order of SCL SL CL. The saturated hydraulic conductivity (Ksat) increased linearly with increasing rate of Ca applied in the leaching water and maximum Ksat was observed for SCL soil followed by SL and CL.