| Summary: | Abstract Atrazine has been intensively applied to control weeds in agriculture and frequently detected in soil far from the point of application due to its special property, which causes serious soil environmental problems. Therefore, the aim of this study was to investigate the effects of environmental concentrations of atrazine (0, 0.1, 1.0, and 10 mg $ kg^{−1} $) on the soil microbial community during 42 days of culture using biochemical and molecular methods. The results showed that the number of culturable bacteria, fungi, and actinomycetes decreased significantly with the increase of atrazine concentration during the whole exposure process, showing a certain dose-effect relationship. Soil microbial biomass carbon also decreased significantly during atrazine exposure. Biolog ECO analysis showed that 10 mg $ kg^{−1} $ treatment had an inhibitory effect on the overall activity of microbial community (AWCD) at the later stage of the experiment (days 28 and 42). Additionally, 10.0 mg $ kg^{−1} $ atrazine treatment for 28 days decreased the richness of the soil microbial community (Shannon), the dominance of common species (Simpson), and the homogeneity of species (Mcintosh). PCR-T-RFLP analysis showed that atrazine exposure significantly affected the structure of bacterial dominant flora in the soil at days 0, 7, 14, and 21. Further PCR-DGGE analysis showed that the dominant bacteria flora mainly belonged to Proteobacteria, Firmicutes, Deinococcus-Thermus, Actinobacteria, and Acidobacteria. Overall, this study demonstrates that atrazine has a certain influence on soil microorganisms and provides an objective assessment of the ecological risk of atrazine to soil microorganisms.
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