title: Simulating concentration of bensulphuron-methyl in a drainage canal of a paddy block using a rice pesticide model.
abstract: A pesticide fate and transport model (PCPF-B) was developed to predict the runoff of pesticides from paddy plots to a drainage canal in a paddy block based on the plot scale model (PCPF-1). The block-scale model now comprises three modules: (1) a module for pesticide application, (2) a module for pesticide behaviour in paddy fields, and (3) a module for pesticide concentration in the drainage canal. The PCPF-B model was first evaluated using published data in a single plot and then was applied to predict the concentration of bensulphuron-methyl in one paddy block in the Sakura river basin, Ibaraki, Japan, where a detailed field survey was conducted. The PCPF-B model simulated well the concentration of bensulphuron-methyl in individual paddy plots. It also reflected the runoff pattern of bensulphuron-methyl at the block outlet, although overestimation of bensulphuron-methyl concentrations occurred due to uncertainty in water balance estimation. A sensitivity analysis showed that the soil adsorption coefficient of the herbicide had the greatest influence on the concentrations and cumulative loss of bensulphuron-methyl to the drainage canal.
authors.affiliation: Department of Bioproduction Environmental Sciences, Faculty of Agriculture, Kyushu University, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Thai Khanh
authors.initials: TK
authors.lastname: Phong
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Hiramatsu
authors.forename: Hirozumi
authors.initials: H
authors.lastname: Watanabe
mesh_terms: D000383:Agriculture / Q000379:methods*; D003198:Computer Simulation; D004323:Drainage, Sanitary; D008962:Models, Theoretical; D012275:Oryza; D010575:Pesticides / Q000032:analysis / Q000737:chemistry*; D013453:Sulfonylurea Compounds / Q000032:analysis / Q000737:chemistry*; D058438:Water Cycle; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D010575:Pesticides; D013453:Sulfonylurea Compounds; D014874:Water Pollutants, Chemical; C071475:methyl bensulfuron