Halosulfuron methyl did not have a significant effect on diversity and community of sugarcane rhizosphere microflora

Halosulfuron methyl (HM) is a new, highly active sulfonylurea herbicide that has been widely used for weed control in agricultural production. However, its potential ecological risks remain unknown. In this study, we investigated the impact of different concentrations of HM on bacterial communities in sugarcane rhizospheric soil by using 16S rRNA gene high-throughput sequencing. The half-life of HM for 130 mg/kg, 600 mg/kg, and 1300 mg/kg spraying concentrations were 6.64, 9.19, and 9.87 d, respectively. HM application did not alter the alpha or beta diversity of the soil bacterial community, whereas some microbial populations and the main microbial functional groups were significantly altered by HM exposure. The phylum Cyanobacteria and genus unclassified Chloroflexi group KD4-96 were found to be positively correlated with HM concentration in soils, indicating that they are highly involved in the biodegradation of HM in soils. Relationship analysis between soil properties and microbial communities showed that total nitrogen and total phosphorus concentration were two key factors that significantly influenced microbial community structure. To our best knowledge, this is the first microbial ecotoxicological assessment of HM in agricultural soil.