Effect of Lime on the Changes in Adsorbed and Soluble Sulphate in Alfisols of Orissa

A laboratory investigation was carried out to study the effect of lime applied with and without gypsum on the changes in adsorbed and soluble SO₄ ^2- at different time intervals in two Alfisols of Orissa. Lime was applied @ 0 and 0.3 LR with three different combinations of sulphur i.e. 0, 20 and 40 μg g^-1 through gypsum. The soils were incubated for a period of 60 days. Soil pH, after liming, increased by 0.3 to 0.6 unit in Dhenkanal soil and 0.4 to 0.9 unit in Jharsuguda soil at different days of the incubation period in different treatments. Soil pH either remained constant or decreased slightly with application of gypsum. There was a significant reduction in exchangeable H+ and Al⁺⁺⁺ after liming. Effect of gypsum on the changes in exchangeable H+ and Al⁺⁺⁺ was insignificant. Application of lime decreased the adsorbed SO₄ ^2- -S by 20.3 to 58.1 % and 30.9 to 47.5 % and increased the soluble by 14.3 to 99.3% and 21.3 to 125.4% in Dhenkanal and Jharsuguda soils, respectively in different treatments at different days of the incubation period. However, adsorbed, soluble and (adsorbed + soluble) were higher in the lime + gypsum treated soils than in the lime treated soils only. There were irregular changes in adsorbed, soluble and (adsorbed + soluble) with increasing days of the incubation period.