Central Kentucky could be considered a critical source area of nutrients in water ways because of low permeability soils, fast groundwater flow through bedrock fractures, and pervasive agriculture and development. Of particular concern is rising development in rural areas, which creates mixed land cover (MLC) watersheds, i.e., watersheds with development, agriculture, and other land cover types. MLC watersheds add complexity to spatial and temporal releases of dissolved constituents, leading to less predictable water quality patterns. The goal of this research was to examine the export of dissolved substances from a small, upland MLC catchment in central Kentucky with a focus on how the interaction between discharges from developed agricultural land cover and groundwater influence base flow water quality. Our approach was to spatially sample a representative catchment monthly over 1 year, characterize the major dissolved constituents, and evaluate catchment processes with statistical analyses and Piper diagrams. Principal component analysis, factor analysis, and Piper diagrams indicate base flow was composed of groundwater influenced by two different host rocks and an outfall draining a developed region. Base flow nutrient export was dominated by mixing nitrate-sulfate rich groundwater with ammonium-phosphate-chloride rich outfall drainage. High nitrate groundwater dominated nitrogen export in the winter, whereas high ammonium outfall drainage dominated summer export. Spatial analysis revealed that ~ 10% of the basin may have similar land cover and hydrologic processes, suggesting that MLC catchments are small but collectively significant nitrogen sources to river networks due to development and agriculturally impacted groundwater.

中文翻译：

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小规模农业流中小规模土地覆盖和地下水相互作用对基流溶质和养分输出的影响。

由于低渗透性土壤，快速的地下水流过基岩裂缝以及广泛的农业和发展，肯塔基州中部被认为是水上养分的重要来源地区。特别令人关注的是农村地区不断发展的发展，这创造了混合土地覆盖（MLC）流域，即具有发展，农业和其他土地覆盖类型的流域。MLC分水岭增加了溶解成分在空间和时间上的释放复杂性，导致水质模式难以预测。这项研究的目的是研究肯塔基州中部一个小型高地MLC集水区的溶解物出口，重点是发达农业土地覆盖物的排放与地下水之间的相互作用如何影响基本流量水质。我们的方法是在1年中每月对一个有代表性的集水区进行空间采样，表征主要溶解成分，并通过统计分析和Piper图评估集水过程。主成分分析，因子分析和Piper图表明，基流由受两种不同宿主岩影响的地下水和排泄发达区域的排泄口组成。基流养分的出口主要是将富含硝酸盐的地下水与富含磷酸铵的氯化物的排污口混合。高硝酸盐地下水占冬季氮素出口的主要部分，而高铵排污口则占夏季出口的主要部分。空间分析显示，流域约有10％的土地覆盖和水文过程相似，