Phosphorus export by runoff from agricultural field plots with different crop cover in Lake Taihu watershed
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 theeffects 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 in 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鷄) for cropland. Most of P loss is in PP form, which accounts for more than 90% of TP loss for cropland.
作 者： YAN Wei-jin HUANG Man-xiang Zhang Shen TANG Yi-jian 作者单位： Department of Environmental Biogeochemistry, Institute of Geographic Science and Natural Resources Research, Chinese Academy of Sciences, 刊 名： 环境科学学报(英文版) ISTIC SCI 英文刊名： JOURNAL OF ENVIRONMENTAL SCIENCES 年，卷(期)： 2001 13(4) 分类号： X59 关键词：