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Development of a Small-Scaled Model Test System for Simulation of Pesticide Runoff
Yoshiyuki TAKAHASHI, Yutaka WADA, Yoshitsugu ODANAKA, Yasushi KAKUTA and Toshikazu FUJITA
J. Pestic. Sci.
25, 217-222 (2000)
A new indoor runoff test system with controlled rain conditions was developed to better understand the field surface runoff mechanism. Containers (0.7 m2) packed with soil of plow layer were used as test plots and placed under a rain-making machine (10¡¾80 mm/hr) at a 5¡ë slope. When rain conditions of a field (840 m2) in runoff were simulated to the test plot after pesticide application (a mixture of chlorothalonil, diazinon and dimethoate), not only amounts of runoff water (l/m2) but also concentrations of runoff pesticides were very similar to those of the field runoff. When the water runoff in the field was predicted by the occurrence conditions in the indoor runoff test system, amounts of predicted runoff water were larger than the collected ones. Some model tests were performed with 30 mm/hr of rainfall and 1 l of runoff water collection. When individual test plots were aged for several periods (1¡¾21 days) after pesticide application, the concentrations of pesticides in water samples decreased with the lapse of time after aging. Furthermore, when concentrations and ratios of runoff pesticides from each test plot with and without plants were compared, the small difference was observed between the test plots with and without plants.
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