Impact of Roundup and Clearfield herbicides on soil nutrients, and the biomass, activity and diversity of soil microorganisms

Front matter only available electronically. The complete thesis in print form is available from the University of Adelaide Library.Roundup and Clearfield are herbicides that have been widely used globally and their use is expected to increase in the coming years. However, these herbicides may affect soil microbes that are important for soil health because of their roles in cycling carbon and soil nutrients. There have been no studies to explore the effect of Clearfield on microorganisms. In this study, the effect of Roundup and Clearfield GM resistant herbicides on microorganisms was investigated. The experiments were designed to measure soil nutrients (available phosphorus and nitrogen), microbial biomass carbon (MBC), and microbial activity (respiration and enzymes) in the soil every 7 days over a 28 day period. Soil microbial diversity was also measured at 28 days using an amplicon sequencing based approach. The results revealed no positive or negative effects of either herbicide at their recommended and five times recommended rates. This study was conducted on soil samples in the lab, but a larger scale studies on the agronomic effects of the two herbicides on microbes in field environments are recommended.Thesis (M.Bio.(PB)) -- University of Adelaide, Masters of Biotechnology (Plant Biotechnology), School of Agriculture, Food and Wine, 2016