Impairment of cellulose- and cellobiose-degrading soil Bacteria by two acidic herbicides

Abstract

Herbicides have the potential to impair the metabolism of soil microorganisms. The current study addressed the toxic effect of bentazon and 4-chloro-2-methylphenoxyacetic acid on aerobic and anaerobic Bacteria that are involved in cellulose and cellobiose degradation in an agricultural soil. Aerobic saccharide degradation was reduced at concentrations of herbicides above environmental values. Microbial processes (e.g. fermentations, ferric iron reduction) that were linked to anaerobic cellulose and cellobiose degradation were reduced in the presence of both herbicides at concentrations above and at those that occur in crop field soil. 16S rRNA gene transcript numbers of total Bacteria, and selected bacterial taxa (Clostridia [Group I], Planctomycetaceae, and two uncultivated taxa of Bacteroidetes) decreased more in anoxic than in oxic cellulose-supplemented soil microcosms in the presence of both herbicides. Collectively, the results suggested that the metabolism of anaerobic cellulose-degrading Bacteria was impaired by typical in situ herbicide concentrations, whereas in situ concentrations did not impair metabolism of aerobic cellulose- and cellobiose-degrading soil Bacteria.

Soil microbial communities and dehydrogenase activity depending on farming systems

“…It is liable that this herbicide might noxiously affect on the bacterial communities, because in the soil of CONFYM treatment the numbers of total bacteria and cellulose decomposers decreased by 21% and 31%, respectively, as compared with the ORGFYM treatment. Our results are similar to the results of Schellenberger et al (2012) who reported about the toxic effect of MCPA on the cellulose degrading bacteria in the water-saturated soil. Such moisture conditions existed in 2010 because during August and September it rained the total of 243 mm.…”

Influence of Agricultural Management Practices on the Soil Properties and Mineral Composition of Potato Tubers with Different Colored Flesh

“…It is liable that this herbicide might noxiously affect the bacterial communities because, in the soil of this system, the soil microbial biomass decreased. Our results are similar to the results of other researchers, who have reported on the toxic effect of MCPA on bacteria [25] and soil enzymatic activity [22]. Previous studies revealed the adverse impacts of pesticides on soil microbial biomass [26,27].…”

Assessment of microbial activity and biomass in different soils exposed to nicosulfuron

“…Cellulose becomes metabolized in soil through the presence of abundant aerobic and anaerobic cellulolytic microorganisms (Schellenberger et al, 2012). Over the initial three days of our bioassay, nicosulfuron caused no change in the abundance of cellulolytic microorganisms in loamy soil (Table 2).…”