Forms of Sulphur and their Relationship with Soil Properties in Entisols, Inceptisols and Alfisols of Assam

Seventy-five surface soil samples representing three soil orders viz., Entisols, Inceptisols and Alfisols of Assam were analysed for various forms of sulphur (S). Entisols contained lowest and Alfisols the highest level of all the fractions of S. Organic S (79.61–82.34%) constituted the dominant form of S in all the orders followed by non-sulphate sulphur (11.19–17.08%). Water soluble and adsorbed S constituted 3.50 and 0.74% of total S pool, 4.07 and 1.66, 7.28 and 4.01% in Entisols, Inceptisols and Alfisols, respectively. The adsorbed S contributed the least to the total S pool in all the soils. All forms of S were positively and significantly linked with total S excluding non-sulphate S in Entisols and Alfisols. The soil organic-C was positively correlated with all forms of S except non-sulphate S.