Dissipation of S-metolachlor in plant and soil and effect on enzymatic activities

Abstract

The present study aimed at evaluating the dissipation of S-metolachlor (S-MET) at three doses in maize growing on diverse physico-chemical properties of soil. The effect of herbicide on dehydrogenase (DHA) and acid phosphatase (ACP) activity was estimated. A modified QuEChERS method using LC-MS/MS has been developed. The limit of quantification (0.001 mg kg−1) and detection (0.0005 mg kg−1) were very low for soil and maize samples. The mean recoveries and RSDs for the six spiked levels (0.001–0.5 mg kg−1) were 91.3 and 5.8%. The biggest differences in concentration of S-MET in maize were observed between the 28th and 63rd days. The dissipation of S-MET in the alkaline soil was the slowest between the 2nd and 7th days, and in the acidic soil between the 5th and 11th days. DT50 of S-MET calculated according to the first-order kinetics model was 11.1–14.7 days (soil) and 9.6–13.9 days (maize). The enzymatic activity of soil was higher in the acidic environment. One observed the significant positive correlation of ACP with pH of soil and contents of potassium and magnesium and negative with contents of phosphorus and organic carbon. The results indicated that at harvest time, the residues of S-MET in maize were well below the safety limit for maize. The findings of this study will foster the research on main parameters influencing the dissipation in maize ecosystems.

Effect of Three Commercial Formulations Containing Effective Microorganisms (EM) on Diflufenican and Flurochloridone Degradation in Soil

“…Our results confirm that the herbicide or its metabolites may stimulate the activity of microorganisms in the first period, while the activity of DHA decreases with dissipation of the active substance [ 22 ].…”

Microbial Diversity and P Content Changes after the Application of Sewage Sludge and Glyphosate to Soil

“…The response of enzymes to changes in soil is a consequence of combination of many biotic and abiotic factors such as the type of fertilization and/or contamination, as well as the type of soil and its physicochemical properties (i.e., pH, organic matter content, humidity, nutrient status), experiment condition (laboratory or field scale) or type of enzyme. When sewage sludge is being used, its origin, treatment technique and contaminant level are important factors influencing soil quality [28,50,52]. In the study conducted by Alvarenga et al [53] no effect of sewage sludge application on Dha activity was demonstrated, which partly confirms our results.…”

Kinetic field dissipation and fate of endosulfan after application on Theobroma cacao farm in tropical Southwestern Nigeria

“…The moisture content of cocoa husk is about 14% (w/w) (Daud et al, 2013), this may have facilitated the hydrolysis of endosulfan in pod tissues to form the diol metabolite. Besides, the presence of some endogenous biological enzymes such as lignin peroxidases and pectin methyl esterase (Falade et al, 2016, Kameshwar andQin 2018) may have enhanced the rapid degradation of endosulfan observed on day 0 in pods (Wolejko et al, 2017). These other metabolites were not determined; endosulfan sulfate is reported to be the major metabolite of endosulfan -which also is an intermediary metabolite to the formation of other metabolites in plants and animals via the endosulfan diol route.…”