title: Phosphorus export by runoff from agricultural field plots with different crop cover in Lake Taihu watershed.
abstract: Runoff and soil losses from agricultural fields are investigated as major nonpoint sources of phosphorus (P) entering lakes of Eastern China. There is relatively little information on P transport from ricefield and cropland of Lake Taihu watershed in Eastern China. Soil and P in surface runoff from a series of plots in the watershed were evaluated under simulated rainfall conditions. The objectives of this study were to evaluate the effects of crop cover, slope, and fertilizer application on P concentrations in surface runoff and eroded soil. Accumulated sediment yields varied from 7.1 to 300 g/m2 for croplands, depending on management practices. For all experiment plots, weighted average concentrations of total-P (TP), dissolved P (DP) and particulate P (PP) are much higher than 0.02 mg/L, the limiting concentration for lake water. This result showed the potential contamination of lake water from agricultural surface runoff. Accumulated TP losses were 3.8 and 18.8 mg/m2 for ricefield and cropland, respectively. The estimated annual loss of TP was 0.74 kg/(hm2.a) for cropland. Most of P loss is in the PP form, which accounts for more than 90% of TP loss for cropland.
authors.affiliation: Department of Environmental Biogeochemistry, Institute of Geographic Science and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China. yanwj@igsnrr.ac.cn
authors.forename: W J
authors.initials: WJ
authors.lastname: Yan
authors.forename: M X
authors.initials: MX
authors.lastname: Huang
authors.forename: S
authors.initials: S
authors.lastname: Zhang
authors.forename: Y J
authors.initials: YJ
authors.lastname: Tang
mesh_terms: D000383:Agriculture; D003247:Conservation of Natural Resources; D004784:Environmental Monitoring; D005068:Eutrophication; D005308:Fertilizers; D012275:Oryza; D010758:Phosphorus / Q000032:analysis*; D011891:Rain; D012987:Soil; D014872:Water Movements
chemical_list: D005308:Fertilizers; D012987:Soil; D010758:Phosphorus