Investigation of Ecotoxicological Effects of Glyphosate (Herbicide) on Soil (Sandy Loam & Sandy Clay Loam) Physiochemical Properties and Microbial Diversity

Abstract

This work showed that the adsorption of glyphosate depends on the textural class and amount of clays and concerntration of exchangeable cations in the soils. Organic matter had a secondary role in the adsorption of glyphosate on soils. This research was conducted to evaluate the influence of glyphosate-based herbicides systems on soil microbial activity. Soil was treated with commercial formulations of glyphosate (applied as Roundup). The soil microbial activity was measured by quantifying carbon and nitrogen mineralization, pH, concerntration of exchangeable cation, concerntration of exchangeable bases. Soil microbial biomass was determined using Nutrient culture media and total viable cell count method. Glyphosate applied at the recommended field rate to a sandy clay loam and a sandy loam non-agricultural soil resulted in few changes in their population but all the species (Bacillus spp, Mold, Staphylococcus spp, Enterococci, Micrococcus spp) isolated were maintained for the duration of the experiment. Total and culturable bacteria biomass, carbon utilization profiles were unaffected for the period of 21days after application of the herbicide. The result therefore suggest that, although the herbicide does not show any toxicity to the microbial community it however causes fluctuation in the microbial population

Keywords: Sandy loam, Sandy clay loam, Glyphosate, Microorganisms, Batch