Effects of fomesafen on soil enzyme activity, microbial population, and bacterial community composition

Abstract

Fomesafen is a diphenyl ether herbicide that has an important role in the removal of broadleaf weeds in bean and fruit tree fields. However, very little information is known about the effects of this herbicide on soil microbial community structure and activities. In the present study, laboratory experiments were conducted to examine the effects of different concentrations of fomesafen (0, 10, 100, and 500 μg/kg) on microbial community structure and activities during an exposure period of 60 days, using soil enzyme assays, plate counting, and denaturing gradient gel electrophoresis (DGGE). The results of enzymatic activity experiments showed that fomesafen had different stimulating effects on the activities of acid phosphatase, alkaline phosphatase, and dehydrogenase, with dehydrogenase being most sensitive to fomesafen. On the tenth day, urease activity was inhibited significantly after treatment of different concentrations of fomesafen; this inhibiting effect then gradually disappeared and returned to the control level after 30 days. Plate counting experiments indicated that the number of bacteria and actinomycetes increased in fomesafen-spiked soil relative to the control after 30 days of incubation, while fungal number decreased significantly after only 10 days. The DGGE results revealed that the bacterial community varied in response to the addition of fomesafen, and the intensity of these six bands was greater on day 10. Sequencing and phylogenetic analyses indicated that the six excised DGGE bands were closely related to Emticicia, Bacillus, and uncultured bacteria. After 10 days, the bacterial community exhibited no obvious change compared with the control. Throughout the experiment, we concluded that 0-500 μg/kg of fomesafen could not produce significant toxic effects on soil microbial community structure and activities.

Effect of long-term industrial waste effluent pollution on soil enzyme activities and bacterial community composition

“…DGGE profiling of soil community DNA fragments enables to monitor the spatial and temporal changes in microbial community structure and provides a comparative picture of the dominant microbial species of polluted soils (Qu et al 2011;Zhang et al 2014). Phylogenetic analysis of 16S rRNA gene clearly indicated the selection in eubacterial community structure with response to IWE pollution.…”

“…In another study, the higher percentage of Proteobacteria, Firmicutes, and Actinobacteria were noticed in long-term polluted soils in which hydrocarbon was the main contaminant (Vivas et al 2008). Pollution-induced bacterial community shifts were observed with organic pollutants such as phenanthrene, fluoranthene, pyrene, benzo(a)pyrene, and herbicides (Tian et al 2008;Zhang et al 2014). Studies suggested that the indigenous bacteria are very sensitive to contaminants and respond rapidly to organic pollutants (Tian et al 2008).…”

Responses of Soil Microorganisms and Enzymatic Activities to Azoxystrobin in Cambisol

“…The plate counting method [13] was applied to measure soil microbial numbers on selective media. Luria-Bertani (LB) medium was used to culture bacterial colonies.…”

Impact of the novel neonicotinoid insecticide Paichongding on bacterial communities in yellow loam and Huangshi soils

“…Many reports showed that insecticides also can alter ecosystems through concentrating along food chain (Stephenson et al 2006). Insecticides are often found in crop, food, soils, and water, and the large amount of insecticide application often leads to insecticide residues in soils, which can affect the soil microbial community by changing their number, microbial activity, and diversity (Zhang et al 2010(Zhang et al , 2014Zabaloy et al 2012;Cycon et al 2013;Cai et al 2015a).…”