广枯灵中甲霜灵在头花蓼及土壤中的残留消解动态

Degradation Dynamics of the Residue of Metalaxyl in Guangkuling in Polygonum capitatum Buch and Soil

采用田间试验及高效液相色谱检测方法，研究了广枯灵中甲霜灵在中药材头花蓼及土壤中的残留消解动态．实验结果表明，甲霜灵在头花蓼和土壤上的半衰期分别为6．7-7．3d和12．6-13．9d．按最高推荐剂量22．5g·a·i／hm^2和2倍高剂量45g·a·i／hm^2使用2-3次，末次施药距收获间隔14d，甲霜灵在头花蓼植株和土壤中的最终残留量均低于我国蔬菜上的最大残留量0．5mg／kg．所以广枯灵中的甲霜灵在贵阳地区头花蓼上按照推荐剂量11．25-22．50g·a·i／hm^2使用2-3次，降解速度较快，不易发生积累作用，使用安全．

Degradation dynamics and final residues of metalaxyl in the fungicide hymexazol-metalaxyl aqueous solution （its Chinese commercial name being Guangkuling） in the Chinese traditional medicinal plant Polygonurn capitaturn Buch were estimated by HPLC. The results showed that the half-life of metalaxyl in P. capitaturn and the soil was 6.7-7.3 days and 12.6-13.9 days, respectively. When the P. capitaturn plants were sprayed twice or three times at the recommended maximum dose of 22.5 g · a · i/ha or even at 45 g · a· i/ha and harvested 14 days after the last application, the residue level of metalaxyl in P. capitatum and the soil was lower than 0. 5 mg/kg, the permissible maximum residue limit on vegetables in China. Therefore, 11.25-22.50 g ·a · i/ha should be a safe recommended dose on P. capitatum in Guiyang region.