植物生长调节剂甲哌鎓在土壤中的降解及其影响因子  

Factors Affecting the Degradation of Mepiquat Chloride in Soil

作　　者：田晓莉[1] 谢湘毅[1] 周春江[2] 杨培珠[3] 王保民[1] 段留生[1] 李松林[2] 恽友兰[2] 何钟佩[1] 李召虎[1] 

机构地区：[1]中国农业大学农学与生物技术学院作物化学控制研究中心,北京100193 [2]北京市农业技术推广站,北京100029 [3]中国农业大学上庄实验站,北京100094

出　　处：《农业环境科学学报》2008年第5期1726-1731,共6页Journal of Agro-Environment Science

基　　金：国家863计划(2003AA246060);农业结构调整重大专项(04207201A);北京市科委科技计划项目(H022020020330)

摘　　要：植物生长调节剂甲哌鎓(DPC)主要用于防止棉花徒长,在我国的应用面积每年达400万hm2以上,用量为75～300g·hm-2,明确其在土壤中的降解及其影响因子可为评价其环境安全性提供依据。在实验室恒温培养条件下应用紫外分光光度法研究了DPC在土壤中的降解动态,该方法的线性检测范围为0～3.5mg·kg-1,添加浓度为1.0～2.0mg·kg-1时,回收率在74.5%～88.8%之间,标准偏差为3.1%～3.6%,变异系数为3.9%～4.2%。研究结果表明,DPC在土壤中的降解包括微生物降解和化学降解两条途径,化学降解和化学降解+微生物降解的平均降解率分别为1.93和3.12%·d-1,半衰期(T1/2)分别为13.0和7.2d,降解95%所需时间(T0.95)分别为53.8和33.2d。另外,土壤温度和湿度对DPC降解均有显著影响,DPC降解的适宜温度为25℃,适宜湿度为饱和持水量的60%～70%,此时平均降解率为(3.0￣3.5)%·d-1,半衰期为8d左右,降解95%所需时间(T0.95)为30￣35d。根据《化学农药环境安全评价试验准则》,DPC属于易降解农药,对环境的影响较小、安全性较高。The plant growth regulator mepiquat chloride（DPC ） is extensively used for preventing the excessive vegetative growth of cotton world-wide. The applied area reaches more than 4 000 000 hectare every year in China, which is more than 70% of the total planting cotton area. Mepiquat chloride is applied at 75-300 g·hm^-2. Laboratory experiments were performed to elucidate the degradation of DPC in soil for estimating the residue and environmental safety. The residue was extracted ultrasonically and determined by an UV Spectrophotometer. The linear range of the method was 0-3.5 mg·kg^-1. The recoveries of DPC were 74.5%-88.8%, with 3.1%-3.6% of standard deviation, and 3.9%- 4.2% of coefficient variations from soil when DPC was applied at 1.0-2.0 mg·kg^-1. One experiment indicated that DPC was degraded by both microbial biodegradation and chemical degradation in the soil. The average degradation rate was 1.93 % d^-1 in sterilized soil, which included chemical degradation alone and 3.12 % d^-1 in non-sterilized soil, which included microbial degradation and chemical degradation together. The T1/2 was 13.0 d in sterilized soil and 7.2 d in non-sterilized soil, and the T0.95 was 53.8 d in sterilized soil and 33.2 d in non-sterilized soil. Another experiment showed that DPC degradation was influenced by both soil temperature and soil moisture. The optimum temperature for DPC degradation was 25 ℃, which is advantageous for both microbial propagation and the enzyme activity. Low temperature （4 ℃ ） or high temperature （35 ℃ ） decreased DPC degradation. The T1/2 was prolonged from 8.4 d to 22.8 d at 4 ℃ and to 9.9 d at 35 ℃. The degradation of DPC was decreased with reduction of the saturation moisture capacity from 70% to 20%. The T1/2 was extended from 7.9 d to 10.3 d.

关 键 词：甲哌鎓 降解 土壤 温度 湿度 

分 类 号：X592[环境科学与工程—环境工程]