ESTIMATING RUNOFF EXPORT RATIO OF PESTICIDE RESIDUE USING RICEWQ MODEL FROM PADDY FIELD

摘要

Runoff export ratio (Ratio between losses by runoff and applied amount of pesticide) of sixpesticides (Diazinon, Oxadiazone, Butachlor and Chlorpyrifos-me, 2,4-d, Carbaryl) frompaddy fi eld was estimated using RICEWQ model. To refl ect water management of actualfarmers, water balance of experimental paddy fi eld in Hampyung, Korea was monitored. Theobserved rainfall, irrigation, runoff, evapotranspiration, and infi ltration in 2007 were 952, 761,665.3, 469 and 406 mm, respectively. Hydrology submodel was calibrated with observed waterbalance results. Laboratory incubation test was conducted and decaying pattern of pesticideconcentrations was monitored. Parameters for pesticide submodel were determined usingincubation test results after calibration. RICEWQ model simulated runoff and concentrations ofthe pesticide with calibrated hydrologic and pesticide submodel under conventional pesticideapplication scenario. Runoff ratio of each pesticide was estimated based on simulated results.When application of pesticide was varied up to 7 days, runoff ratio of Butachlor, Oxadiazone,Chlorpyrifos-me, Diazinon, 2,4-d and Carbaryl varied 13.1 ~ 17.5, 1.2 ~ 1.4, 0.57 ~ 0.66,12.0~ 20.5 %, 21.9 ~ 28.9 %, and 12,7 ~ 14.3 % respectively. In general, the longer half-life ofpesticide resulted in the higher runoff ratio.