Influence of Endosulfan on Microbial Biomass and Soil Enzymatic Activities of a Tropical Alfisol

The effect of endosulfan at normal residue level (1 and 10 ppm) and elevated level (100 ppm) on microbial biomass and enzymatic activities of a tropical alfisol was studied. Dehydrogenase, Fluorescein diacetate hydrolase, acid phosphatase, aryl sulphatase activities and microbial biomass of the soil increased by 2.4, 1.7, 1.4, 1.8 and 3.7 times, respectively by the 14th day of incubation with 1 ppm endosulfan, indicating the possible involvement of soil microorganisms and their enzymes in degradation of endosulfan. Soil nitrogenase activity decreased by 8.0 times by the 14th day of application of 1 ppm endosulfan, suggesting that endosulfan or its metabolites may pose toxicological threat to nitrogen fixers in soil.