Abstract: An analytical method and the degradation behavior in the ecological environment of paddy field for the residues of Bentazon (48% aqueous formulationt is reported. The degradation half lives of bentazon in rice grain, soil and water were calculated. If the herbicide was sprayed once during the three-leaf stage of herbs 60 days before harvest with the application volumn of 300ml/mu deluted to 50 liters by water, the final residues of bentazon and its metabolites in rice grain would be bellow the minimun detected limits (0.02 mg/kg).

Key words: Bentazon, Pesticide residue and degradation behavior, Degradation half life, Paddy field

摘要： 报道了48％排草丹水剂在水稻上的残留分析方法及稻田生态环境中残留消解动态试验研究，计算出排草丹在稻株、土壤和水中降解半衰期。每亩施用3.0 m1，兑水50 kg,在杂草2～3叶期喷施一次，距收期60天,稻谷中排草丹及其代谢产物的最终残留量低于最低检出浓度0．02 mg／kg。

关键词: 排草丹, 残留消解动态, 降解半衰期, 稻田