除草剂氟磺胺草醚在不同土壤中的环境行为

Environmental behavior of herbicide fomesafen in different soil types

利用液相色谱分析法，研究了氟磺胺草醚在不同类型土壤（白浆土、草甸土、黑土）中的残留和淋溶动态。结果显示，氟磺胺草醚以有效成分1350g·hm-2的剂量施用时，在3种类型土壤中的降解符合一级动力学反应，半衰期分别为：草甸土25．7～26．7d，白浆土16．9～19．3d，黑土26．7～30．1d；在120d内，氟磺胺草醚在不断降解代谢的同时，逐渐向深层土壤中淋溶，但多数氟磺胺草醚滞留在表层土壤中。在白浆土中，施用氟磺胺草醚30d后淋溶深度达到30cm，第60天10～30cm土层的氟磺胺草醚浓度达到最大；在草甸土和黑土中，氟磺胺草醚施用后第5天的淋溶深度即达30cm，第14天10～30cm土层的氟磺胺草醚浓度达到最大。结果表明，氟磺胺草醚在有机质含量较高的土壤环境中不容易降解，土壤理化性质是影响氟磺胺草醚淋溶作用的主要因素之一，在草甸土和黑土中氟磺胺草醚对后茬作物的残留药害及对地下水的潜在污染大于白浆土。

In this study, fomesafen residue and its leaching dynamics in three types of soil were clarified by high performance liquid chromatography （ HPLC ）. When fomesafen was applied with the active ingredient at 1350 g · hm 2, the half-lives of degradation in the meadow, albic and black soils were 25.7-26.7, 16.9-19.3, and 26.7-30.1 days, respectively, which were con- sistent with the first-order reaction kinetics model. Fomesafen leached gradually with its degrada- tion in soil during 120 days, while most of it retained in the surface soil. In the albic soil, fome- safen leached to 30 cm after 30 days of application and the concentration of fomesafen in 10-30 cm soil reached the maximum after 60 days. In the meadow and black soils, the leaching depths were up to 30 cm after 5 days, and the concentrations of fomesafen in 10-30 cm soil reached the maximum after 14 days. These results indicate that fomesafen is hard to degrade in a soil with a high organic matter content, and the soil physical and chemical properties are main factors influ- encing fomesafen leaching. The residue toxicity of fomesafen on following rotation crops and its potential pollution to groundwater in the meadow soil and black soils were heavier than in the albic soil.