灭多威在棉花及土壤中的残留行为研究

Study on Residual Behavior in Cotton and Soil of Methomyl

为了解灭多威施用后在棉田中的残留降解行为,全面准确评价灭多威的生态环境安全性,指导其科学合理施用,笔者通过动态及残留实验,研究了灭多威在棉花及其土壤上的动态降解及最终残留行为。结果表明:施药3d后,灭多威在棉田土壤和棉叶中的消解率均大于50%;施药28d后,灭多威在棉田土壤和棉叶中的消解率均在90%以上。灭多威在湖南长沙的棉田土壤和棉叶中的半衰期为11.39d和10.04d;在河北石家庄的棉田土壤和棉叶中的半衰期为9.99d和8.94d。灭多威在棉田土壤中的最终残留量均低于0.50mg/kg;在棉叶中的最终残留量均低于0.40mg/kg;在棉籽中的最终残留量均低于最小检出量0.02mg/kg。研究表明灭多威在棉田土壤和棉叶中的降解速度较快,属易降解农药。按推荐剂量在棉田中使用,对棉田环境影响较低,可在生产实际中推广使用。

In order to find out the residual degradation of Methomyl after it had been used in cotton field, assess completely and correctly the bio-environmental safety of Methomyl, and guide how to use it in scientific and rational way. This paper research dynamic degradation and final residual behavior in cotton and soil of Methomyl, by means of dynamic and residual experiment. The results indicated that the degradation rates in cotton soil and cotton leaves both exceeded 50%, after Methomyl had been used for 3 days; and the degradation rates exceeded 90% after Methomyl had been used for 28 days. The half life of Methomyl in cotton soil and cotton leaves was 11.39 days and 10.04 days in Changsha, Hunan province; and it was 9.99 days and 8.94 days in Shijiazhuang, Hebei province. The final residual quantity of Methomyl both below 0.50 mg/kg in cotton soil, below 0.40 mg/kg in cotton leaves. The final residual quantity of Methomyl in cotton seed both below the minimum detectable activity 0.02 mg/kg. The research indicated that Methomyl degrade fast in cotton soil and cotton leaves, which belong to easily degradable pesticide. Methomyl would have a lower impact on environment, if it was used in cotton field according to recommended dose, so it could be applied in the agricuhure production.