Sulphate sorption and buffering capacity in some soils of Assam

A study was undertaken to relate the sulphate sorption characteristics and buffering capacities in some soils with soil properties covering three major soil orders viz., Entisols, Inceptisols and Alfisols of Assam. Both sorption and maximum sulphur buffering capacity (MSBC) of these soils varied widely among the soils. Alfisols, in general, showed maximum sulphate sorption capacity ranging from 91.6 to 1300 μg g⁻¹ along with highest MSBC (35.6 to 418 mL g⁻¹). Among the soil orders, Entisols, in general, showed lowest MSBC with 19.2 to 32.8 mL g⁻¹ and lowest sulphate sorption capacity varying from 58.2 to 399 μg g⁻¹. Such differences in sulphate sorption and MSBC were attributed to differences in their soil pH, amount of amorphous and crystalline oxides of Fe and Al, organic carbon content and available sulphate pools of these soils.