Microbial Community’s Dynamic Response to Fomesafen Usage in Chernozems of Northeast China

Fengshan Yang,Mingrui Yuan,Yanbo Wang,Yanan Huang,Yuning Wei,Haiyan Fu,Weimin Zeng,Chunguang Liu

doi:10.3390/d13080340

Abstract

The main purpose of this study was to explore the effects of the recommended usage level and twice the recommended usage level of the long-acting herbicide fomesafen on the soil enzymes and microbial community structure in chernozems of soybean fields. Culturable microbial biomass and phospholipid fatty acids (PLFA) were used as the main references for this evaluation. The digestion curve of fomesafen in soil conforms to the law of a single exponential function. The activities of four soil enzymes decreased significantly when exposed to twice the recommended amount, and then returned to the control level. The inhibition of the fungal and bacterial biomass section of culturable microorganisms in soil at twice the recommended usage level was greater than that under the recommended usage level, and this dosage also stimulated the rapid recovery of the initial level of fungal biomass before the application of fomesafen. The PLFA analysis showed that the ratio of GN/GP decreased significantly, and soil pressure increased significantly. Compared with the recommended usage level, the effect of twice the recommended usage level of fomesafen on soil microbial community structures was more significant. This provides a reference for environmental location recommendations, environmental safety assessments, and the rational use of herbicides.

Highlights

The residue dynamics of of variation between 1.46 and 3.86%, indicating that the extraction method and the testing fomesafen in the soybean field applied at the recommended level and twice the recomconditions met the requirements of pesticide residue analysis
Following the first day ofand spraying with the fomesafen in the applied at the recommended level twice the recommended usage level in of
This study clearly shows that the inhibitory effect of using twice the recommended level of fomesafen on four soil enzymes was significantly higher than that of using the recommended level

Summary

Introduction

Published: 26 July 2021Fomesafen, which is a diphenyl ether herbicide developed by AstraZeneca (UK), is used to remove broadleaf weeds in soybean, fruit tree, and rubber estate fields in China [1].Fomesafen was first exported to China in 1988, and was first produced in China in 1994, becoming a widely used and effective herbicide by the beginning of the 20th century [2,3].Since fomesafen is a long-acting residual herbicide with a half-life ranging from 10 days to several months, its residue dynamics in soil should be assessed [4,5,6].The application of a pesticide can effectively prevent disastrous losses of grain yield and promote economic growth in the agricultural industry, but its degradation is affected by many factors, including soil type, pH, organic matter content and soil microbial communities. Previous authors have reported a residual half-life of fomesafen of 133 days when used in a soybean field of anthrosols in Hangzhou, and of 14.2 days when used in a soybean field of anthrosols in Chuzhou [9]. They studied the degradation of fomesafen in Gongzhuling chernozems in the Jilin Province, and observed that the initial slow degradation rate became more rapid on days 60–90, with yielded half-lives of approximately 87 days for applications of both

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