李慧，姜滨，黄择祥，刘莉，邱军，于卫松，孙惠青

摘  要：为明确甲霜灵、噁霜灵和烯酰吗啉3种农药从土壤向烟草叶片的迁移降解及在不同部位叶片中的分布特征，在烟田进行灌根施药，采用GC-MS/MS测定农药残留量，研究了灌根施药方式对烟叶农药残留的影响。结果表明，灌根施药后，3种农药在土壤中的残留量逐渐降低且降解动态符合一级动力学方程;在烟叶中的残留量先升高后降低，不同部位的残留量呈现下部叶>中部叶>上部叶的趋势。甲霜灵、烯酰吗啉在施药后第7天烟叶农药残留量低于最大残留限量标准，噁霜灵在施药后第28天烟叶农药残留量仍高于最大残留限量标准。可见，按推荐高剂量进行灌根施药后，烟叶中甲霜灵、烯酰吗啉超限风险较低，噁霜灵超限风险较高。

关键词：烟草;农药残留;迁移降解;安全性

The Migration and Degradation Characteristics of Three Pesticides in the Soil-Tobacco Plant System

LI Hui1， JIANG Bin2， HUANG Zexiang2， LIU Li3， QIU Jun1， YU Weisong1， SUN Huiqing1*

（1. Tobacco Research Institute， Chinese Academy of Agricultural Sciences， Qingdao 266101， China; 2. China Tobacco Corporation Shandong Branch， Jinan 250101， China; 3. Shandong Linyi Tobacco Co.， Ltd.， Yishui， Shandong 276400， China）

Abstract： In order to clarify the migration and degradation of metalaxyl， oxadixyl and dimethomorph from soil to tobacco leaves and their distribution characteristics in different parts of leaves， the effects of root irrigation application methods on pesticide residues in tobacco leaves were studied by GC-MS/MS. The results showed that the residues of the three pesticides in soil decreased gradually after root irrigation， and the degradation dynamics accorded with the first-order kinetic equation. The residues in different parts of tobacco plants showed the trend of lower leaves>middle leaves>upper leaves. The pesticide residues of metalaxyl and dimethomorph in tobacco leaves were lower than the maximum residue limit on the 7th day after application， and the pesticide residues of oxadixyl in tobacco leaves were still higher than the maximum residue limit on the 28th day after application. It can be seen that the risk of metalaxyl and dimethomorph overrun in tobacco leaves was lower， and the risk of oxadixyl overrun was higher after the recommended high dose of root irrigation.

Keywords： tobacco; pesticide residues; migration and degradation; safety

化學农药在现代农业生产中发挥了不可或缺的作用，是现代农业发展的物质保障。由于长期大量使用化学农药，土壤中不可避免地存在农药残留[1]。农药进入土壤的途径有以下几种：一是灌根施药进入土壤;二是叶面喷施后降落或淋洗进入土壤;三是大气中的农药沉降进入土壤[1-5]。

施用的农药进入土壤后，会通过挥发、扩散、吸附、生物降解、光化学降解等多种途径进行迁移转化[6-8]。其中，植物可以通过发达的根系从土壤中吸收农药并转运至地上部位[9-10]，从而对农产品造成污染，危害人体健康[4，11-12]。

农药在土壤-植株系统中迁移富集规律的研究较少。张贝贝等……