Impacts of glyphosate and its formulation on soil microbial function

The herbicide glyphosate is an important tool for weed management, but there are concerns that it negatively impacts on soil health. The thesis examined the impact of glyphosate and a commercial formulation (RoundupCT^®) on soil functions. A meta-analysis of published literature showed no impacts of glyphosate on soil microbial biomass (SMB) or respiration at field rates, but at higher doses inhibition of soil microbial biomass (SMB) was detected. Laboratory studies demonstrated that soil microbial communities and functions were generally resilient to high doses of glyphosate in loam and clay soils, but sandy soils were more at risk. Nevertheless, at field application rates, glyphosate or its commercial formulation RoundupCT™ had negligible longer-term effect on soil function.