DIFFERENTIAL RESPONSE OF SOIL TEXTURE FOR LEACHING OF SALTS RECEIVING DIFFERENT PORE VOLUMES OF WATER IN SALINE-SODIC SOIL COLUMN

This study examined the leaching requirement of three saline-sodic soils in polyvinyl chloride (PVC) columns of 50 cm long and 11 cm internal diameter. Air-dried soils were packed in PVC lysimeters receiving different pore volume (PV) of water (EC 0.89 dS m^-1, SAR 1.55, RSC 1.02 mmolc L^-1). Leaching with 2.5 PV of water removed 94 % of soluble salts and decreased ECe from 33.9 to 5.9 dS m^-1 in 0-25 cm layer of sandy clay loam soil. For lowering ECe to 4 dS m^-1 in loamy sand up to 0-25 cm soil layer, 2.0 PV water removed 67 % soluble salts. In silty clay loam soil, 2.5 PV water lowered ECe to 4 dS m^-1 only up to 0-10 cm depth with 83 % removal of salts. Relationships between EC/EC0 and Dw/Ds established were for the soils as EC/EC0 = 0.329 (Dw/Ds)^-2.12 with r= 0.87 for loamy sand; EC/EC0 = 0.167 (Dw/Ds)-0.60 with r=0.89 for silty clay loam and EC/EC0 = 0.06 (Dw/Ds)0.78 with r=0.98 for sandy clay loam soil. These relationships leads to conclude that reduction in salinity of loamy sand, silty clay loam and sandy clay loam soil was 67, 83 and 94 % when leached with 1.88, 2.72 and 2.67 cm of water, respectively.