Fate and transport of carbofuran under application in rice field by application of root zone water quality model (RZWQM)

Abstract

Most of the land in Khon Kaen Province, located in Northeast Thailand, is used for agricultural purposes and, therefore, contains fertilizers and pesticides. These additives may have harmful impacts on ecosystems and human health. One of the widely used pesticides is carbofuran. It is used to control soil-dwelling and foliar-feeding insects e.g. boll weevils, mosquitoes, and white grubs. This study illustrates the fate and transport of carbofuran in rice field using the Root Zone Water Quality Model (RZWQM). The concentrations of the pesticide under several different agricultural management scenarios were determined. In ten years simulation from 1999 to 2008, the overestimated concentration of residual carbofuran was equal to 32.80 kg/ha at the end of year 2008. Using a sensitivity analysis, it was determined that soil subsurface aerobic and abiotic system significantly have impact on dissipation/degradation of carbofuran in soil. Other parameters, which have effects on carbofuran concentration in soil, include the number of pesticide applications, soil hydraulics, and type and amount of water source. The pesticide can rapidly transport into soil profile that mainly caused by water leaching.