Influence of Herbicide Triasulfuron on Soil Microbial Community in an Unamended Soil and a Soil Amended with Organic Residues

Abstract

The effect of organic amendments and pesticides on a soil microbial community has garnered considerable interest due to the involvement of microorganisms in numerous soil conservation and maintenance reactions. The aim of this work was to assess the influence on a soil microbial community of the simultaneous application of the herbicide triasulfuron at three doses (2, 10, and 50 mg kg-1), with an organic amendment [sewage sludge (SS) or green compost (GC)]. Dissipation kinetics, soil microbial biomass, dehydrogenase activity (DHA) and respiration, and the profile of phospholipid fatty acids (PLFAs) extracted from the soil, were determined in unamended (S) soil and amended (S+SS and S+GC) ones. Triasulfuron dissipation followed the single first-order kinetics model. Half-life (DT50) values were higher in the amended soils than in the unamended one for the 10 and 50 mg kg-1 doses. The dissipation rates were lower in the S+GC soil for the three herbicide doses applied. In general, soil biomass, DHA and respiration values increased in SS- and GC-amended soils compared to the unamended one. DHA values decreased (S and S+SS) or increased (S+GC) with the incubation time of soil with herbicide at the different doses applied. Respiration values increased with the herbicide doses applied and decreased with the incubation time, although maximum values were obtained for soils treated with the highest dose after 70 days of incubation. PLFA analysis indicated different effects of triasulfuron on the soil microbial community structure depending on the organic amendments. While the increasing triasulfuron doses resulted in deeper alterations in the S soil, the time after triasulfuron application was the most important variation in the S+SS and S+GC soils. The overall results indicate that the soil amendment has an effect on herbicide dissipation rate and the soil microbial community. Initially, a high dose of triasulfuron had detrimental effects on the soil microbial community, which is important in the case of the long-term use of this compound.

Application of green compost as amendment in an agricultural soil: Effect on the behaviour of triasulfuron and prosulfocarb under field conditions

“…The DT 50 values found in this study are within the range observed in other field studies on unamended soils (< 50 days) (Sarmah et al, 2000;EFSA, 2015), but they are lower than those obtained in laboratory experiments (33-76 days) (James et al, 1999;EC, 2000;Pose-Juan et al, 2017). Mobility into deeper layers was one the factors proposed for trisulfuron increased dissipation in the field.…”

“…The results indicating the increased DT 50 values of triasulfuron in the GCamended soil are in agreement with the adsorption coefficients K d of triasulfuron for the soil+GC (0.53 mL g -1 ) (Table S3, in Supplementary material), and higher than in the unamended soil (0.05 mL g -1 ). An increased adsorption of this herbicide by soils amended with different composted organic residues has also been reported in laboratory studies (Said-Pullicino et al, 2004;Pose-Juan et al, 2017). However, the addition of straw residues as organic amendment increased the dissipation of triasulfuron in lab experiments, but not in the field (Menne and Berger, 2001).…”

“…The dissipation of triasulfuron herbicide has been studied in the laboratory and in the field (EC, 2000;Gennari et al, 2008), while only some laboratory studies have evaluated the effect of the herbicide's application dosage (Sofo et al, 2012, Pose-Juan et al, 2017 or the influence of OM on its adsorption and dissipation in amended soils (Said-Pullicino et al, 2004;Pinna et al, 2009;Pose-Juan et al, 2017). Evaluating the changes in mobility and the persistence of this herbicide by soil amendment is therefore of interest, as it could impact negatively on the performance of future crops (Menne and Berger, 2001;Sarmah et al, 1998Sarmah et al, , 2000.…”

Changes in microbiological properties of soil during fungicide degradation

“…Global pesticide production increases every year by about 11%, with herbicides, insecticides and fungicides dominating in the sales structure (Carvalho 2017). Long-term and intensive application of these agents can lead to extensive treated of soil ecosystems (Pose-Juan et al 2017). As Ye et al (2018) reports, even 80-90% of applied pesticides penetrate into the natural environment, and only a small percent (1-2%) operate against the target organisms, while the remaining share (10-20%) is situated on the plant surface.…”

“…As Ye et al (2018) reports, even 80-90% of applied pesticides penetrate into the natural environment, and only a small percent (1-2%) operate against the target organisms, while the remaining share (10-20%) is situated on the plant surface. This can have a harmful effect on the quantity and quality of microorganisms inhabiting the soil, as well as on their physiological processes, which is related to unfavourable changes in soil productivity and fertility (Pose-Juan et al 2017). It is very important to determine the response of microorganisms and soil enzymes to pesticides in soil in view of their participation in biogeochemical cycles and their role in maintaining proper soil functions and promoting growth and development of plants (Grz¹dziel andGa-³¹zka 2018, Siwek-Ziomek andKoper 2018).…”