Department of Biological Systems Engineering, Virginia Tech, Blacksburg, VA, USA.
Department of Biological Systems Engineering, Virginia Tech, Blacksburg, VA, USA.
Sci Total Environ. 2018 Sep 1;635:132-143. doi: 10.1016/j.scitotenv.2018.04.110. Epub 2018 Apr 13.
Agricultural conservation practices (CPs) are commonly implemented to reduce diffuse nutrient pollution. Climate change can complicate the development, implementation, and efficiency of agricultural CPs by altering hydrology, nutrient cycling, and erosion. This research quantifies the impact of climate change on hydrology, nutrient cycling, erosion, and the effectiveness of agricultural CP in the Susquehanna River Basin in the Chesapeake Bay Watershed, USA. We develop, calibrate, and test the Soil and Water Assessment Tool-Variable Source Area (SWAT-VSA) model and select four CPs; buffer strips, strip-cropping, no-till, and tile drainage, to test their effectiveness in reducing climate change impacts on water quality. We force the model with six downscaled global climate models (GCMs) for a historic period (1990-2014) and two future scenario periods (2041-2065 and 2075-2099) and quantify the impact of climate change on hydrology, nitrate-N (NO-N), total N (TN), dissolved phosphorus (DP), total phosphorus (TP), and sediment export with and without CPs. We also test prioritizing CP installation on the 30% of agricultural lands that generate the most runoff (e.g., critical source areas-CSAs). Compared against the historical baseline and with no CPs, the ensemble model predictions indicate that climate change results in annual increases in flow (4.5±7.3%), surface runoff (3.5±6.1%), sediment export (28.5±18.2%) and TN export (9.5±5.1%), but decreases in NO-N (12±12.8%), DP (14±11.5), and TP (2.5±7.4%) export. When agricultural CPs are simulated most do not appreciably change the water balance, however, tile drainage and strip-cropping decrease surface runoff, sediment export, and DP/TP, while buffer strips reduce N export. Installing CPs on CSAs results in nearly the same level of performance for most practices and most pollutants. These results suggest that climate change will influence the performance of agricultural CPs and that targeting agricultural CPs to CSAs can provide nearly the same level of water quality effects as more widespread adoption.
农业保护措施（CPs）通常用于减少分散的营养污染。气候变化可以通过改变水文学、养分循环和侵蚀来复杂化农业 CPs 的开发、实施和效率。本研究量化了气候变化对水文、养分循环、侵蚀以及美国切萨皮克湾流域萨斯奎哈纳河流域农业 CP 有效性的影响。我们开发、校准和测试了土壤和水评估工具-可变源区（SWAT-VSA）模型，并选择了四个 CPs；缓冲带、条播、免耕和排水，以测试它们在减少气候变化对水质影响方面的有效性。我们用六个降尺度的全球气候模型（GCMs）为历史时期（1990-2014 年）和两个未来情景时期（2041-2065 年和 2075-2099 年）驱动模型，并量化了气候变化对水文、硝酸盐-N（NO-N）、总氮（TN）、溶解磷（DP）、总磷（TP）和有无 CP 的泥沙输出的影响。我们还测试了在产生最大径流量的农业土地的 30%（例如，关键源区-CSA）优先安装 CP。与历史基线相比，在没有 CP 的情况下，综合模型预测表明，气候变化导致流量（4.5±7.3%）、地表径流（3.5±6.1%）、泥沙输出（28.5±18.2%）和 TN 输出（9.5±5.1%）的年增长率增加，但 NO-N（12±12.8%）、DP（14±11.5%）和 TP（2.5±7.4%）的输出减少。当模拟农业 CPs 时，大多数不会明显改变水量平衡，但是，排水和条播减少了地表径流、泥沙输出和 DP/TP，而缓冲带减少了 N 的输出。在 CSA 上安装 CP 几乎对所有实践和大多数污染物都具有相同的效果。这些结果表明，气候变化将影响农业 CPs 的性能，而将农业 CPs 针对 CSA 可以提供与更广泛采用几乎相同的水质效果。
