A tiered assessment approach based on standardized methods to estimate the impact of nicosulfuron on the abundance and function of the soil microbial community
Date
2014
Authors
Karpouzas, D.G.
Kandeler, E.
Bru, D.
Friedel, I.
Auer, Y.
Kramer, S.
Vasileiadis, S.
Petric, I.
Udikovic Kolic, N.
Djuric, S.
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Journal article
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Soil Biology and Biochemistry, 2014; 75:282-291
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Abstract
Pesticides impact soil microorganisms in various ways. Despite the pivotal role of the latter in ecosystem functioning, the assessment of pesticides soil microbial toxicity is lagging behind the recent methodological advances in microbial ecology. We investigated the impact of nicosulfuron, a low dose sulfonylurea herbicide, on the structure, abundance and function of the soil microbial community using standardized methodologies (PLFAs, taxa-specific qPCR and enzyme activities). For this purpose a Tiered approach involving assessment i) at extreme, long term (five repeated application cycles) exposure schemes in a microcosm experiment conducted under greenhouse conditions (x0, x10, x100 and x1000 the recommended dose, Tier I) and ii) at realistic field exposure scenarios (x0, x1, x2 and x5, Tier II) was followed. Significant reductions in the abundance of Gram negative (b-proteobacteria, planctomycetes) and Gram positive bacteria (actinobacteria) were indicated by both PLFA and qPCR analyses at low soil concentrations of nicosulfuron (0.25e1 mg g 1), while a reduction of fungi at equally low levels of nicosulfuron in soil was found only by qPCR analysis. C- and P-cycling enzymes were particularly sensitive even at low soil concentration of the herbicide (0e1 mg g 1). In contrast, no inhibitory effects of nicosufluron at field conditions were found. The only exception was cellobiohydrolase which were impaired at herbicide rates higher than the recommended. We suggest that the use of a tiered microcosm-to-field experimentation combined with the application of standardized methodologies could provide a comprehensive assessment of the soil microbial toxicity of pesticides.
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Data source: Supplementary data, https://doi.org/10.1016/j.soilbio.2014.04.022
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Copyright 2014 Elsevier