不同土壤中苯噻草胺的微生物降解

研究了除草剂苯噻草胺在不同土壤中的降解。结果表明，有机质含量低的土壤中微生物降解是其消失的主要因素，有机质含量高的黑土中吸附结合是其消失的主要因素。水田条件下苯噻草胺消失速率比旱田条件下快，但消失类型不同。被吸附的农药在解吸前不参与微生物降解，土壤有机质含量影响苯噻草胺的实际降解速率。提出反 S型函数模型更好地拟合农药在土壤中的消失动态。

Degradation of Mefenacet in Different Soils

The dissipation of mefenacet was studied in different soils. The results showed that in the soil with less organic matter, microbial degradation was the main factor for the disappearance of mefenacet, while in the soil with more organic matter, adsorption was the main factor. Mefenacet disappeared more quickly in paddy soil than in glebe, revealing that its disappearing processes were different. It has been also indicated by the present test that mefenacet that had been adsorbed was not degraded by desorption. The actual dissipation rate was influenced by the content of organic matter in soil. In this research, it was indicated that the function of anti－ S more exactly fit the degradation dynamics of mefenacet than does traditional first order dynamic.