模拟降雨对百菌清在小白菜上的淋失效应

The leaching effect of chlorothalonil on pakchoi by simulated rainfall

为探究降雨对露地蔬菜上农药沉积的淋失影响,以百菌清为供试农药,以小白菜为代表作物,采用人工模拟降雨研究了不同降雨强度、雨滴大小、降雨间隔、降雨次数、降雨连续性、小白菜生育期及室内外生长环境对百菌清在小白菜上沉积量的淋失影响。结果表明:百菌清在小白菜上的残留量随着降雨强度增大而降低;随着雨滴直径增大而降低;随着降雨间隔时间增加而升高;随着降雨次数的增多而降低,达到一定次数趋于稳定;且间断降雨对百菌清的淋失作用大于连续降雨。小白菜生长前期百菌清淋失率远低于生长中后期。施药24h后,室内生长小白菜上百菌清的淋失率高于室外。百菌清施药后48 h内,残留量受降雨影响较大;48 h后在小白菜上具有较高的抗雨刷性。

In order to explore the effect of rainfall on pesticide deposition loss on open vegetables,the effect of rainfall intensity,rain drop size,rainfall interval,rainfall frequency,rainfall continuity,fertility period and indoor and outdoor growing environment on the amount of pesticide deposited on pakchoi was investigated by artificial rainfall simulations,using chlorothalonil as the test pesticide and pakchoi as the representative crop.The results showed that the residual amount of chlorothalonil on pakchoi decreased with increasing rainfall intensity,decreased with increasing rain drop diameter,increased with increasing rainfall interval time,decreased with increasing rainfall frequency,reached a certain amount of stabilization;and the effect of intermittent rainfall on chlorothalonil was greater than continuous rainfall.The loss rate of chlorothalonil in the early growth stage of pakchoi was much lower than that in the middle and late growth stages.After 24 hours of application,the leaching loss rate of chlorothalonil in indoor growing pakchoi was higher than that in outdoor growing pakchoi.Within 48 hours after application of chlorothalonil,the residue was greatly affected by rainfall.After 48 hours,it showed higher windshield wiper resistance on pakchoi.