Release of Non-exchangeable Sodium from Saline Water Irrigated Vertic Ustochrepts

Soils irrigated with different SAR water were repeatedly extracted with normal potassium and magnesium acetate (KOAc and MgOAc) to find the release of non exchangeable sodium and changes in its cationic bondin genergy during leaching. The release of Na decreased rapidly with progressive extraction. KOAc extracted more sodium than MgO Ac but the differences were small to detect significant amounts of non-exchangeableNa and zeolite. Quasicrystal formation and differences in hydration state seemed to cause partial immobilisation of sodium in case of MgO Ac extraction. The CEC of K-saturated soil was slightly higher than the Mg-saturated one. The ESP determined by using these values differed slightly but correlated significantly (r=0.99) with the routine method. The sodium was loosely bound with the clay in soils irrigated with waters having SAR of 19 and more. The bonding of sodium increased with repeated extractions. The results indicated that reclamation of soils irrigated with high SAR water would require more amendment.