Adsorption and translocation of sulfur in some tropical acid soils

Abstract

In view of growing concern about sulfur (S) deficiency, we attempted to study the effect of soil characteristics on the adsorption and translocation of S in soils. Laboratory experiments were conducted with five surface soils collected from three regions in the state of Orissa (Eastern India). In an adsorption study, all the soils were equilibrated with graded doses of potassium sulfate (K2SO4). Freundlich adsorption isotherms provided good fit to S adsorption data. Free Fe2O 3 and Al2O3 in the soils were primarily responsible for retaining added S in soils. Further, studies on the movement of sulfate-S in 30-cm plexiglass columns, where radio-labeled S along with water (5 cm) was applied as gypsum and K2SO4, showed that K 2SO4-S migrated deeper than gypsum-S. Sulfur moved deeper in case of initially water-saturated soils than in initially air-dry soils.