Sustainable agricultural practices influence s-metolachlor, foramsulfuron and thiencarbazone-methyl degradation and their metabolites formation

• Published in: The Science of the total environment 2024-10, Vol.945, p.174039, Article 174039
• Main Authors: Douibi, Marwa, Rodríguez-Cruz, M. Sonia, Sánchez-Martín, María J., Marín-Benito, Jesús M.
• Format: Article
• Language: English
• Subjects: Conservation agriculture; Dissipation; Herbicide; Metabolite; Mulch; Soil
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.174039

The effect of sustainable agricultural practices, such as mulching or the application of straw residues as an organic amendment, on the degradation, dissipation and persistence in the soil of S-metolachlor (SMOC), foramsulfuron (FORAM) and thiencarbazone-methyl (TCM) is still unclear. The objective here was to conduct a laboratory experiment to evaluate the impact of milled wheat straw (WS) simulating its individual use as mulch or applied as an organic amendment to two agricultural soils: unamended and WS-amended soils on the degradation kinetics of the herbicides SMOC, FORAM and TCM, and on the formation of their major metabolites at two incubation temperatures (14 °C and 24 °C). The degradation rate of SMOC on WS was 6.9–16.7 times faster than that observed for FORAM and TCM at both temperatures. The half-life (DT50) values were 1.1–10.6 times lower for FORAM than for SMOC and TCM in the unamended and WS-amended soils at 14 °C and 24 °C. The application of WS to soils increased the DT50 values from 1.1 to 11.2 times for all the herbicides at both incubation temperatures due to their higher adsorption and lower bioavailability. The herbicides recorded a faster degradation at 24 °C (1.2–3.9 times) than at 14 °C, according to Q10 values >1. SMOC metabolites were more persistent in WS-amended soils than in unamended ones, in agreement with the DT50 values recorded for the parent compound. The results indicate that the effect of the mulch applied to soils as an organic amendment was different depending on the herbicide and incubation temperature. The outcomes of this research can give key suggestions for reducing the effects of residual herbicides following sustainable agricultural practices by avoiding soil and groundwater contamination, which is one of the challenges involved in the application of chemical inputs. [Display omitted] •Degradation of three herbicides in wheat straw (WS) and WS-amended soils was assessed.•The degradation rate of SMOC on WS was more rapid than that observed for FORAM and TCM.•The half-lives (DT50) were lower for FORAM than for SMOC and TCM in the unamended and WS-amended soils.•WS in soils increased the DT50 of all herbicides at 14°C and 24°C due to their higher adsorption.•Sustainable agricultural practices modify the behaviour of herbicides in WS mulching and WS-amended soils.