Effects of soil-applied herbicides on bacterial community structure and diversity of rapeseed field soil.

Soil sealing treatment is an effective chemical weed control method in rapeseed field. To evaluate the effects of different soil-applied herbicides on soil microorganisms in rapeseed field, 16S rRNA amplicon sequencing was used to analyze the changes in soil microbial structure and diversity after treatment with four commonly used soil-applied herbicides alachlor, acetochlor, metochlor and s-metolachlor. The results showed that soil-applied herbicide treatments could significantly reduce soil bacterial diversity in rapeseed fields, and alachlor had the greatest effect on soil bacterial diversity. However, after a period of herbicide treatment, the diversity and richness of the soil bacterial community gradually recovered. Soil-applied herbicide treatment had great influence on Actinomycetes, Acidobacteria and others in rapeseed soil, and alachlor treatment showed the greatest change in soil bacteria at phylum level compared with other herbicides. After 60 days of treatment with soil-applied herbicides, the abundances of functional bacteria related to pollutant degradation, denitrification, photosynthesis, pathogen growth inhibition and rhizosphere growth promotion were increased, whereas functional bacteria associated with the absorption of nutrients and excretion of metabolites were reduced. Overall, the results indicated that the soil-applied herbicides had a certain effect on soil microbial diversity and community structure in rapeseed field, but the effect of herbicides on soil microbial diversity gradually decreased along with the time of treatment. [ABSTRACT FROM AUTHOR]