模拟条件下三唑磷在稻田中的分布、迁移、消解及相关环境因子的影响

Distribution,movement and dissipation of triazophos in rice plant and the impact of related environmental factors through the simulated experiments

采用室内模拟方法研究了三唑磷在水稻-水-土壤中的分布、迁移及消解情况,探讨了三唑磷的消解与环境温度、光照及降雨的关系。结果表明:于水稻苗期喷施药液,0～3 d内三唑磷主要分布在田水和土壤中,第7 d至试验结束时则主要吸附、积累于水稻植株中;三唑磷在水稻、田水和土壤中的消解半衰期分别为4.45、1.56和5.24 d,相互间存在显著差异(P<0.05);在不同温度(25、35、50℃)下,三唑磷的水解半衰期分别为35.13、19.76和3.97 d,其消解速率随温度升高而显著加快(P<0.05);在照度为19 000 lx、不同光周期(10 h/d、14 h/d)下,三唑磷在水稻上的消解半衰期分别为5.70和4.17 d,14 h/d下的消解速率显著高于10 h/d下的(P<0.05);模拟降雨试验中,三唑磷在水稻植株上的残留量随雨强的增大而显著减小(P<0.05),在固定雨强条件下,施药后2 h内降雨对植株上残留三唑磷的冲刷作用较为明显(P<0.05)。

Through the simulated experiments,the mechanism of distribution,movement and dissipation of trizophos in the ecosystem of rice-water-soil was investigated and the impact of environmental temperature,photoperiod and rainfall on dissipation of triazophos were also analyzed.The trial of distribution,movement and dissipation of triazophos in the system of rice-water-soil indicated triazophos mostly distributed in water and soil during 0-3 d,and then it distributed in rice plant from the 7 d to the end of trial.The half-lives of triazophos were 4.45 d,1.56 d and 5.24 d in rice plant,water and soil respectively,which had significant differences（P0.05）.Under temperature of 25 ℃,35 ℃ and 50 ℃,the hydrolytic rate of triazophos rose significantly with increasing of the temperature（P0.05）,and the half-lives of triazophos were 35.13 d,19.76 d and 3.97 d,respectively.The dissipation rate of triazophos in rice under the photoperiod of 14 h/d was faster than that under the photoperiod of 10 h/d when the same light intensity was used（P0.05）.The half-lives of triazophos in rice under the photoperiod of 10 h/d and 14 h/d were 5.70 d and 4.17 d,respectively.The triazophos deposition depleted significantly with increasing of the rainfall intensity（P0.05）;Under the fixed rainfall intensity condition,a rainfall after treatment within two hours had significantly effect on the triazophos residues in rice plant（P0.05）.