Assessing soil ecosystem disruption by mesosulfuron methyl and iodosulfuron methyl using an Integrated Biomarker approach

This study examines the individual and combined effects of mesosulfuron methyl and iodosulfuron methyl on herbicide degradation, leaching, and soil enzymatic and microbial activities. Results showed that the combination of both herbicides enhanced their dissipation and increased their vertical mobility in the soil. Mesosulfuron methyl was more persistent in the soil compared to iodosulfuron methyl. When applied together, the herbicides reached higher concentrations at lower soil depths and in leachates than when applied individually. Mesosulfuron methyl caused the greatest suppression of microbial and enzymatic activities (75.68-92.35% up to 90 days), followed by iodosulfuron methyl (66.7-72.99% up to 45 days). The combined application resulted in the least inhibition (45.77-56.45% up to 21 days). After the initial suppression, microbial and enzymatic activities gradually recovered as the toxic effects of the herbicides diminished. Integrated Biomarker Response (IBRv2) values indicated that mesosulfuron methyl had a stronger impact on soil activities compared to iodosulfuron methyl. However, the combination of both herbicides exhibited an antagonistic effect, suggesting that their combined use could reduce the adverse effects on soil health. The study highlights further investigation into the long-term impacts of herbicide combinations and the development of sustainable guidelines for their agricultural use.