Effect of some Additives on the hydrolysis, persistence and the downward Movement of Glyphosate and Fluazifop-butyl Herbicides

Abstract

The first objective was to determine the effect of additives and water type on the degradation of glyphosate and fluazifop-butyl herbicides.  Both glyphosate and fusillade were strongly hydrolysed in hard water more than Nile water and distilled water. Most additives were decreased glyphosate persistence in all types of water. Glyphosate plus glue was more persistent than glyphosate alone and when mixed with the following additives (urea, glycerine, dioleate, monoleate, paraffin and mineral oil), respectively. Fusilade alone was more persistent than its mixture with the additives rape seed oil, mineral oil, paraffin oil, dioleate and monoleate, respectively. The second objective was to deal with the effect of additives soil texture interactions on persistance and leaching of glyphosate and fluazifop-butyl herbicides. Persistence of glyphosate in clay soil was lower than in sandy soil. Most additives increased half life of glyphosate in clay soil, while glyphosate additive mixtures decreased its stability in sandy soil. Fluazifop-butyl was rapidly dissipated in clay soil more than the sandy soil. Whereas most of the used adjuvant decreased fluazifop-butyl half life in each soil. Glyphosate was not detected in the soil leachate of clay and sandy soil column. The majority of glyphosate and fluazifop-butyl amount was located in the top layer of soil column followed by fewer amounts in the successive layers. Whereas glyphosate and fluazifop-butyl could be transferred from the sub- surface to the following layer from sandy soil with some additives (surfactants) to the following layer. Meanwhile fusillade with surfactants was detected in sandy soil column leaching with non significant amount.