State Key Laboratory of Environment Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing, 100875, China,
Environ Monit Assess. 2014 Dec;186(12):9011-22. doi: 10.1007/s10661-014-4061-6. Epub 2014 Sep 19.
Best management practices (BMPs) have been widely used in managing agricultural nonpoint source pollution (ANSP) at the watershed level. Most BMPs are related to land use, tillage management, and fertilizer levels. In total, seven BMP scenarios (Reforest1, Reforest2, No Tillage, Contour tillage, and fertilizer level 1-4) that are related to these three factors were estimated in this study. The objectives were to investigate the effectiveness and cost-benefit of these BMPs on ANSP reduction in a large tributary of the Three Gorges Reservoir (TGR) in China, which are based on the simulation results of the Soil and Water Assessment Tool (SWAT) model. The results indicated that reforestation was the most economically efficient of all BMPs, and its net benefits were up to CNY 4.36×10(7) years(-1) (about USD 7.08×10(6) years(-1)). Regarding tillage practices, no tillage practice was more environmentally friendly than other tillage practices, and contour tillage was more economically efficient. Reducing the local fertilizer level to 0.8-fold less than that of 2010 can yield a satisfactory environmental and economic efficiency. Reforestation and fertilizer management were more effective in reducing total phosphorus (TP), whereas tillage management was more effective in reducing total nitrogen (TN). When CNY 10,000 (about USD 162) was applied to reforestation, no tillage, contour tillage, and an 0.8-fold reduction in the fertilizer level, then annual TN load can be reduced by 0.08, 0.16, 0.11, and 0.04 t and annual TP load can be reduced by 0.04, 0.02, 0.01 and 0.03 t, respectively. The cost-benefit (CB) ratios of the BMPs were as follows: reforestation (207 %) > contour tillage (129 %) > no tillage (114 %) > fertilizer management (96 and 89 %). The most economical and effective BMPs can be designated as follows: BMP1 (returning arable land with slopes greater than 25° to forests and those lands with slopes of 15-25° to orchards), BMP2 (implementing no tillage on arable land with slopes less than 15°), and BMP5 (0.8-fold less than that of 2010).
最佳管理措施（BMPs）已广泛应用于流域层面的农业非点源污染（ANSP）管理。大多数 BMPs 与土地利用、耕作管理和肥料水平有关。本研究共估计了与这三个因素相关的七种 BMP 情景（重新造林 1、重新造林 2、免耕、等高耕作和肥料水平 1-4）。这些研究的目的是基于土壤和水评估工具（SWAT）模型的模拟结果，调查这些 BMPs 在三峡水库（TGR）一条大型支流中减少农业非点源污染的有效性和成本效益。结果表明，重新造林是所有 BMP 中最具经济效益的措施，其净效益高达人民币 43.6×10^7 元/年（约合 7.08×10^6 美元/年）。就耕作实践而言，免耕比其他耕作实践更环保，等高耕作更具经济效益。将当地肥料水平降低到 2010 年的 0.8 倍，可以实现令人满意的环境和经济效益。重新造林和肥料管理对减少总磷（TP）更有效，而耕作管理对减少总氮（TN）更有效。当应用于重新造林、免耕、等高耕作和肥料水平降低 0.8 倍时，每年 TN 负荷可分别减少 0.08、0.16、0.11 和 0.04t，每年 TP 负荷可分别减少 0.04、0.02、0.01 和 0.03t。BMP 的成本效益（CB）比如下：重新造林（207%）>等高耕作（129%）>免耕（114%）>肥料管理（96%和 89%）。最经济有效的 BMP 可以指定为：BMP1（将坡度大于 25°的耕地和坡度为 15-25°的耕地还林），BMP2（在坡度小于 15°的耕地上实行免耕），BMP5（2010 年减少 0.8 倍）。
