Abstract

                                ins change in the concentration of cations, with time, of alkali and saline soils under reclamation was investigated in a pot culture experiment with PVR. 1 and CO. 32 paddy for alkali soils, and SR 26 B and CO. 32 for saline soils. Alkali soils were treated with either 5 tonnes of gypsum or 5 tonnes gypsum plus 5600 kg green manure per hectare. Saline soil was leached with water either alone or with green manure. Gypsum alone was as efficacious as gypsum plus green manure in increasing exchangeable calcium of alkali soils and decreasing exchangeable sodium by about 50 per cent in 10 days. The decrease in exchangeable sodium was still higher at 30th and 45th days. Increase in exchangeable calcium was higher in open textured alkali soil than in close-textured solls. Close relationships between water-soluble and exchangeable calcium and sodium were observed. In the saline soil water-soluble calcium decreased from 0.029 to 0.097 per cent, and water soluble sodium decreased from 0.7 to 0.09 per cent by about 4th day of leaching. Green, manure application for the saline soil was not beneficial.

Key words :