Agriculture is the main source of diffuse nutrient pollution in surface waters. It requires best management practices (BMPs) for controlling the discharges of pollutants like total nitrogen (TN) and total phosphorous (TP). In addition, these pollutants are accounted in the grey water footprint (GWF) of agricultural productions. This study proposes an integrated methodology with two steps for assessing the impacts of BMPs on the water footprints (WF) of agricultural productions. First, this approach uses the soil and water assessment tool (SWAT) for basin modeling and calculating the required data for WF assessment. In the second step, the WFs of agricultural productions are quantified and compared in different BMP scenarios, including fertilizer and irrigation reduction (FIR) and the application of vegetated filter strips (VFS). The SWAT modeling shows that FIR and VFS are more effective on TN and TP reduction, respectively. It can estimate that the combination of BMPs has the potential of abating 60% of the TN and TP concentrations of lake in 8 years. However, the WFs of agricultural productions may not be significantly reduced by BMPs as the average GWF only constitutes 4.2% of WF in this basin. For instance, the combination of FIR and VFS can reduce the average WF of cereals from 44 to 41 m3/km2. Nevertheless, this practice is relatively more effective for irrigated crops. The WF of rain-fed crops remains constant on 37 m3/km2, while it is reduced 24% (from 91 to 69 m3/km2) for irrigated crops by BMPs. In addition, it is realized that FIR can adversely reduce the production yields up to 32%. All these findings verify that the proposed methodology can integrate BMP and WF assessments by SWAT modeling and is recommended for basins, where farmlands are the dominated land-use. The soil and water assessment tool (SWAT) is used for water quality assessment Best Management Practices (BMPs) are evaluated by the SWAT model Water footprint of agricultural productions are quantified in different BMPs The soil and water assessment tool (SWAT) is used for water quality assessment Best Management Practices (BMPs) are evaluated by the SWAT model Water footprint of agricultural productions are quantified in different BMPs

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最佳管理实践 (BMP) 对农业生产水足迹的影响评估

农业是地表水中弥散养分污染的主要来源。它需要最佳管理实践 (BMP) 来控制总氮 (TN) 和总磷 (TP) 等污染物的排放。此外，这些污染物被计入农业生产的灰水足迹 (GWF)。本研究提出了一种包含两个步骤的综合方法，用于评估 BMP 对农业生产水足迹 (WF) 的影响。首先，该方法使用土壤和水评估工具 (SWAT) 进行流域建模并计算 WF 评估所需的数据。第二步，在不同的 BMP 情景下对农业生产的 WF 进行量化和比较，包括肥料和灌溉减少 (FIR) 和植被过滤带 (VFS) 的应用。SWAT 建模表明，FIR 和 VFS 分别在减少 TN 和 TP 方面更有效。可以估计，BMPs 的组合有可能在 8 年内减少 60% 的湖泊 TN 和 TP 浓度。然而，BMPs 可能不会显着降低农业生产的 WF，因为平均 GWF 仅占该流域 WF 的 4.2%。例如，FIR 和 VFS 的结合可以将谷物的平均 WF 从 44 减少到 41 m3/km2。尽管如此，这种做法对于灌溉作物来说相对更有效。雨养作物的 WF 保持不变，为 37 m3/km2，而 BMP 对灌溉作物的 WF 降低了 24%（从 91 到 69 m3/km2）。此外，FIR 可以不利地降低高达 32% 的生产良率。所有这些发现都验证了所提出的方法可以通过 SWAT 建模整合 BMP 和 WF 评估，并推荐用于农田是主要土地利用的流域。水土评估工具 (SWAT) 用于水质评估 最佳管理实践 (BMP) 由 SWAT 模型评估 农业生产的水足迹在不同的 BMP 中量化 水土评估工具 (SWAT) 用于水质量评估 最佳管理实践 (BMP) 由 SWAT 模型评估 农业生产的水足迹在不同的 BMP 中量化