Abstract Interactions among soil water processes and the nitrogen (N) cycle govern biological productivity and environmental outcomes in the earth's critical zone. Soil water influences the N cycle in two distinct but interactive modes. First, the spatio-temporal variation of soil water content (SWC) controls redox coupling among oxidized and reduced compounds, and thus N mineralization, nitrification, and denitrification. Secondly, subsurface flow controls the movement of water and dissolved N. These two processes interact such that subsurface flow dynamics control the occurrence of relatively static, isolated soil solution environments that span a range of reduced to oxidized conditions. However, the soil water-N cycle is usually treated as a black box. Models focused on N cycling simplify soil water parameters, while models focused on soil water processes simplify N cycling parameters. In addition, effective ways to deal with upscaling are lacking. New techniques will allow comprehensive coupling of the soil water-N cycle across time and space: 1) using hydrogeophysical tools to detect soil water processes and then linked to electrochemical N sensors to reveal the soil N cycle, (2) upscaling small-scale observations and simulations by constructing functions between soil water-N cycle and ancillary soil, topography and vegetation variables in the hydropedological functional units, and (3) integrating soil hydrology models with N cycling models to minimize the over-simplification of N biogeochemistry and soil hydrology mechanisms in these models. These suggestions will enhance our understanding of interactions among soil water dynamics and the N cycle, thus improving modeling of N losses as important sources of greenhouse gas emissions and water pollution.

中文翻译：

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跨空间尺度耦合土壤水过程和氮循环：潜力、瓶颈和解决方案

摘要 土壤水分过程和氮 (N) 循环之间的相互作用控制着地球关键区域的生物生产力和环境结果。土壤水以两种不同但相互作用的模式影响氮循环。首先，土壤含水量 (SWC) 的时空变化控制氧化和还原化合物之间的氧化还原耦合，从而控制氮矿化、硝化和反硝化。其次，地下流动控制水和溶解氮的运动。这两个过程相互作用，使得地下流动动力学控制相对静态、孤立的土壤溶液环境的发生，这些环境跨越一系列还原到氧化的条件。然而，土壤水-氮循环通常被视为一个黑匣子。专注于氮循环的模型简化了土壤水分参数，而专注于土壤水分过程的模型简化了氮循环参数。此外，还缺乏应对升级的有效方法。新技术将允许跨时间和空间的土壤水-氮循环的全面耦合：1) 使用水文地球物理工具检测土壤水过程，然后连接到电化学 N 传感器以揭示土壤 N 循环，(2) 放大小规模观测通过构建土壤水-氮循环与水土功能单元中的附属土壤、地形和植被变量之间的函数进行模拟，以及（3）将土壤水文模型与氮循环模型相结合，以尽量减少氮生物地球化学和土壤水文机制的过度简化在这些模型中。这些建议将增强我们对土壤水分动力学和氮循环之间相互作用的理解，