Sulphur Mineralisation and Oxidation Potential of Some Soil Types of Kerala

Four soil types from Kerala viz. sandy (Oxic Quartzipsamments), red sandy loam (Arenic Paleustults), laterite (Oxic Haplustults) and kari (Tropic Fluvaquents) were taken for studying their rate of S-mineralization and oxidation potential. In case of kari, sandy and laterite soils, the cumulative SO_4^2--S ntineralisation increased up to 40 days after incubation, then reached a plateau after 60 days and subsequently, increased after 80 days of incubation. In case of red sandy loam, increase in SO_4^2--S mineralisation was noticed up to 40 days after incubation followed by a slight decline and subsequent, increase after 80 days of incubation. Oxidised sulphur after six days of incubation was found to be highest in kari soil followed by sandy, laterite and red sandy loam soils. The oxidative capacity of the soils for sulphur followed the same trend.