EFFECT OF PESTICIDES ON MICROBIAL TRANSFORMATION OF SULPHUR IN SOIL

A pot study was conducted in the laboratory of Department of Agricultural Chemistry and Soil Science, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal, India in the year 2007-2008 to investigate the effect of pesticides, on the microbial transformation of sulphur (S) in soil. Insecticide (Endosulfan), fungicide (Dithane M-45), herbicide (2,4-D) were added to the soil at their recommended doses, respectively and their effect on the proliferation and potentiality of thiosulphate oxiding bacteria, aryl sulphatase, available and total sulphur were investigated in soil. The results of the present investigation revealed that insecticide, endosulfan effectuated a significant detrimental effect on some microbiological, biochemical and chemical properties in soil whereas fungicide, dithane M-45 caused a significant detrimental influence during the later stages in spite of stimulating influence at early stages incubation period. However, herbicide, 2,4-D, brought about a beneficial influence on the microbiological, biochemical and chemical properties in soil. Among the pesticides used in the study, the performance of the herbicide was favorable in all respect.