烟稻轮作田土壤中二氯喹啉酸残留阈值分析

为明确烟稻轮作田土壤中二氯喹啉酸导致烟草药害的残留阈值，研究了稻田不同施药剂量下二氯喹啉酸的残留量和降解规律，分析了残留量和烟草药害等级相关性。结果表明，土壤中较低浓度的二氯喹啉酸残留就可导致烟草药害。稻田推荐剂量的二氯喹啉酸在植烟土壤中半衰期为25.7 d，施用60 d后降解率为77.83%。移栽后60 d，土壤中二氯喹啉酸残留量与烟草药害等级呈指数关系，残留阈值为0.006 mg/kg，如超过此阈值，烟草会产生明显药害症状。烟田规划期即烟草移栽前60 d，二氯喹啉酸残留风险值为0.072 mg/kg。研究为控制二氯喹啉酸药害风险和烟田规划提供了理论依据和数据支撑。

Analysis of the Residual Threshold Value of Quinclorac in Tobacco-Rice Rotation Soil

In order to determine the residual threshold value of quinclorac in tobacco-rice rotation soil, the residue and degradation of quinclorac in the soil under different dosages were studied, and the correlation between the residue of quinclorac and the phytotoxicity level of tobacco was analyzed. The results showed that low concentration of quinclorac residues in soil could lead to tobacco damage. The half-life of quinclorac recommended in rice field was 25.7 days, and the degradation rate was 77.83% after 60 days. At 60 days after transplanting, there was a good exponential relationship between the residual amount of quinclorac and the phytotoxicity level of tobacco, and the residual threshold was 0.006 mg/kg. If the residual threshold was exceeded, tobacco would have obvious phytotoxicity symptoms. During the planning period of tobacco field, i.e. 60 days before transplanting, the residual risk value of quinclorac was 0.072 mg/kg. The research provided theoretical basis and data support for controlling the risk of quinclorac and tobacco field planning.