Degradation and Effects of Pesticides on Soil Microbiological Parameters-A Review*

Abstract

Intensive use of agrochemicals mainly pesticides in natural environments have become a major concern and have stimulated scientists to develop reliable methods to assess the potential for the transformations of these anthropogenic chemicals. These information are very much essential for modelling the fate and effects of these chemicals in the environment. This article is a review of the information available in the literature highlighting the various soil properties, which will influence the degradation of pesticides. The extent of biodegradability depends upon the chemical structure of the pesticides. Soil physico-chemical properties influence the transformation of pesticides to a great extent. Soil microbial components largely govern pesticide degradation in soil. Maintenance of soil quality constitutes considerable intervention in the research agenda. Soil microbial biomass and its activities are important attributes of soil quality. The impact of pesticides on the soil microbial biomass, ergosterol content, respiration and fluorescein diacetate hydrolyzing activity as available in the literatures is reviewed here with especial emphasis. Most of the pesticides at field application rate did not impair the soil biological parameters. At higher rates of application the suppressive effects were transitory. Studies revealed positive correlation between pesticide transformation rate, soil physico-chemical and biological properties. Ecophysiological parameters, like the ratio of basal soil respiration to microbial biomass (qCO2), are helpful to detect the stress on microorganisms due to pesticides. Most of the studies were conducted under laboratory conditions. Field studies are conspicuously lacking in the world literature. Future research need is projected.