Maize herbicides mixtures effects on soil microbial communities : microcosms studies

Overview & Synopsis

These experiments are part of the actual problematic of understanding the poorknown effects of pesticides mixtures in soil ecosystem. The herbicidal commercial formulations of S-metolachlor (Dual Gold Safeneur®), mesotrione (Callisto®) and nicosulfuron (Milagro®) were applied in mixtures at the recommended field rate. Formulated compounds are more toxic than active ingredients alone (Microtox®) and no synergistic or antagonistic effects were recorded. However, these mixtures impaired rapidly and transitory the Limagne soil microbial communities, without modifying the global parameters of structure and abundance. Effects were also recorded on sensitive communities, such as phototrophic, nitrifying and denitrifying communities. A comparison of mixtures effects on phototrophic communities from two soils underlined the high toxicity of Dual Gold Safeneur® and challenged its use from an ecotoxicological point of view..