engleski

Ecotoxicological impact of low dose pesticide nicosulfuron on soil microbial biodiversity and functioning

EU report of the working group established under “the thematic strategy soil protection” aiming at preparing the EU proposal concerning the soil framework, have clearly identified agriculture as a major threat for soil biodiversity and functioning. In response to these agrochemical firms started to develop new pesticides working at low concentration for which very few environmental data are yet recorded. In this context ECOFUN- MICROBIODIV, a SEE.ERA.NET-funded project, was settled with the aim to estimate the ecotoxicological impact of low dose herbicide nicosulfuron (NS), belonging to the sulfonylurea family, on soil microbial biodiversity and functioning. Although this herbicide is applied worldwide, its impact on soil microflora remains poorly described. The project was based on an interdisciplinary approach conducted at different scale, from the field plot to the greenhouse. The specific objectives of the project were settled and aimed at (i) characterizing the fate of NS in the soil therefore defining the exposure of soil microbial communities to NS, (ii) estimating the impact of NS on the microbial diversity by using approaches: fumigation/extraction of soil microbial biomass (fungal and bacterial species), phospholipid fatty acid analysis (PLFA), automated ribosomal interspacer analysis (A-RISA), 16S rDNA psequencing, (iii) estimating the impact of NS on the soil functional biodiversity by targeting two bacterial communities involved in nitrogen (amoA) and carbon cycling (pcaH and catA) and one fungal community forming a symbiosis with most of the plants (endomycorrhizal fungi), (iv) estimating NS impact on communities harboring acetohydroxyacid synthase gene targeted by the NS , (iv) monitoring the adaptation of soil microflora by isolating nicosulfuron resistant bacteria and characterizing NS-degrading strains. The results will give new insights in the ecotoxicological impact of herbicide on soil microflora functional biodiversity and is hoped to stimulate research towards the development of guidelines for assessing pesticides toxicity on the soil functional microbial diversity for regulatory purposes.

herbiced; soil; agriculture; nicosulfuron; soil microbail community

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