Effect of water management practice on pesticide behavior in paddy water
Effect of water management practice on pesticide behavior in paddy water
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DOI：
10.1016/j.agwat.2006.10.009
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发表时间：
2007-03
期刊：
影响因子：
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通讯作者：
Hirozumi Watanabe;M. Nguyen;Komany Souphasay;S. Vu;T. Phong;J. Tournebize;S. Ishihara
中科院分区：
文献类型：
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作者：
Hirozumi Watanabe;M. Nguyen;Komany Souphasay;S. Vu;T. Phong;J. Tournebize;S. Ishihara
使用两种水管理实践对日本水稻生产中常用的三种除草剂的归宿和迁移进行了比较。除草剂为西草净、硫苯威和苯芬那特。第一种管理做法是使用带有高排水门的自动灌溉系统（AI）的间歇灌溉方案，第二种管理做法是在试验稻田中采用连续灌溉和溢流排水方案（CI）。除草剂的消散似乎遵循一级动力学，半衰期 (DT50) 为 1.6–3.4 天，DT90（90% 消散）为 7.4–9.8 天。即使在大降雨期间，AI 方案也几乎没有排水，因此导致每种施用的除草剂通过径流损失不到 4%。与此同时，CI 方案导致西草净、硫苯威和苯芬那特的施用质量分别损失约 37%、12% 和 35%。使用带有高排水闸门的自动灌溉系统的间歇灌溉方案节省了灌溉水并防止了除草剂径流，而连续灌溉和溢流方案导致了水和除草剂的大量损失。保持过量的水储存对于防止重大降雨事件期间稻田水径流非常重要。与水溶性 (SW) 相比，有机碳分配系数 Koc 似乎是除草剂水生命运的有力指标。然而，需要进一步调查来了解 Koc 和农业实践与农药归宿和运输之间的关系。建议将日本目前规定的 3-4 天的基于 DT90 的除草剂施用后持水期延长至 10 天，这是控制稻田除草剂径流的良好农业实践。此外，建议在保水期间使用的最佳水管理做法是使用带有高排水闸门的自动灌溉系统的间歇灌溉方案。
The fate and transport of three herbicides commonly used in rice production in Japan were compared using two water management practices. The herbicides were simetryn, thiobencarb and mefenacet. The first management practice was an intermittent irrigation scheme using an automatic irrigation system (AI) with a high drainage gate and the second one was a continuous irrigation and overflow drainage scheme (CI) in experimental paddy fields. Dissipation of the herbicides appeared to follow first order kinetics with the half-lives (DT50) of 1.6–3.4 days and the DT90(90% dissipation) of 7.4–9.8 days. The AI scheme had little drainage even during large rainfall events thus resulting in losses of less than 4% of each applied herbicide through runoff. Meanwhile the CI scheme resulted in losses of about 37%, 12% and 35% of the applied masses of simetryn, thiobencarb and mefenacet, respectively. The intermittent irrigation scheme using an automatic irrigation system with a high drainage gate saved irrigation water and prevented herbicide runoff whereas the continuous irrigation and overflow scheme resulted in significant losses of water as well as the herbicides. Maintaining the excess water storage is important for preventing paddy water runoff during significant rainfall events. The organic carbon partition coefficient Kocseems to be a strong indicator of the aquatic fate of the herbicide as compared to the water solubility (SW). However, further investigations are required to understand the relation between Kocand the agricultural practices upon the pesticide fate and transport. An extension of the water holding period up to 10 days after herbicide application based on the DT90from the currently specified period of 3–4 days in Japan is recommended to be a good agricultural practice for controlling the herbicide runoff from paddy fields. Also, the best water management practice, which can be recommended for use during the water holding period, is the intermittent irrigation scheme using an automatic irrigation system with a high drainage gate.