Effect of Exchangeable Sodium on Hydraulic Conductivity of Soils

Clay, clay loam, silty clay loam, silty ham, loam and loamy sand soils of U. P. were incubated with Na₂CO₃ (0, 15, 25, 35, 45, 55 & 65 per cent of CEC) in order to obtain increasing levels of exchangeable sodium. An increase in exchangeable sodium percentage was accompanied by a marked decrease in hydraulic conductivity. The fractional changes in hydraulic conductivity [K/Kmax) were 0.85 at 5.01 E.S.P., 0 52 at 14.43 E.S.P., 0.21 at 24.50 E.S.P., and 0.06 at 29.88 E.S.P.