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.