title: Water quality modeling to evaluate BMPs in rice paddies.
abstract: A water quality model applicable to rice paddies was developed using field data from 1999-2002. Use of the Dirac delta function efficiently explained the nutrient-concentration characteristics of ponded water. The model results agreed reasonably well with the observed data. The ponded-water quality was influenced primarily by fertilization; nutrient concentration was especially high during early cultivation periods. Reducing surface drainage during the fertilization period may substantially reduce nonpoint source loading from paddies. Increased weir heights and shallow irrigation methods were evaluated by the model as practical methods for reducing nutrient loading from paddies. These methods were effective in reducing surface drainage and are suggested as "best management practices" (BMPs) if applied based on site-specific paddy conditions.
authors.affiliation: Research Division, Korea Environment Institute, 613-2 Bulgwang-dong, Eunpyeong-gu, Seoul 122-706, Korea. jihongjeon@hanmail.net
authors.forename: J H
authors.initials: JH
authors.lastname: Jeon
authors.forename: C G
authors.initials: CG
authors.lastname: Yoon
authors.forename: H S
authors.initials: HS
authors.lastname: Hwang
authors.forename: K W
authors.initials: KW
authors.lastname: Jung
mesh_terms: D000383:Agriculture / Q000379:methods*; D004784:Environmental Monitoring / Q000379:methods*; D005308:Fertilizers; D007723:Korea; D008962:Models, Theoretical; D009584:Nitrogen; D012275:Oryza; D010573:Pesticide Residues / Q000032:analysis; D010758:Phosphorus; D011891:Rain; D012989:Soil Pollutants; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014876:Water Pollution; D014881:Water Supply
chemical_list: D005308:Fertilizers; D010573:Pesticide Residues; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D010758:Phosphorus; D009584:Nitrogen