Impacts of Subsurface Tile Drainage on Age—Concentration Dynamics of Inorganic Nitrogen in Soil
Impacts of Subsurface Tile Drainage on Age—Concentration Dynamics of Inorganic Nitrogen in Soil
复制标题
地下瓦排水对土壤中无机氮年龄-浓度动态的影响
DOI：
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发表时间：
2019
影响因子：
5.4
通讯作者：
Praveen Kumar
中科院分区：
文献类型：
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作者：
D. Woo;Praveen Kumar
我们探讨了农田中瓷砖排水沟对硝酸盐、非移动的铵、移动的氨和铵以及氯化物等非反应性示踪剂的年龄和浓度动态的影响。我们实现了两个移动的相互作用的孔隙域捕获矩阵和优先流路径耦合生态水文和地球化学模型，Dhara。我们将此模型应用于一个农业农场，该农场利用位于美国中西部的集中管理景观临界区观测站的玉米-大豆轮作。在一般情况下，我们观察到低浓度和年龄的硝酸盐的地区被归类为地形凹陷，即使存在瓷砖排水沟。此外，在安装瓷砖排水后，观察到移动的氨/铵的年龄增加。这与硝酸盐、固定铵和非反应性示踪剂的情况相反。这些结果的出现是因为由于瓷砖排水导致的移动的氨/铵的消耗导致从非移动的铵到移动的氨/铵的高迁移率通量，其还将相当大量的相对老的氮从非移动的铵携带到移动的氨/铵。这些结果说明了风暴事件尺度动态如何影响流出的空间异质性和时间变异性，这有助于解开土壤中氮动态的复杂性。这一认识有助于精准农业的氮肥应用，以减少对环境的影响。
We explore the impacts of tile drains in agricultural fields on the coupled age and concentration dynamics of nitrate, immobile ammonium, mobile ammonia and ammonium, and nonreactive tracers such as chloride. We implement two mobile interacting pore domains to capture matrix and preferential flow paths in a coupled ecohydrology and biogeochemistry model, Dhara. We apply this model to an agricultural farm that utilizes a corn‐soybean rotation in the Midwestern United States located in the Intensively Managed Landscapes Critical Zone Observatory. In general, we observe both low concentration and age of nitrate in the areas that are classified as topographic depressions even with the presence of tile drains. Also, an increase in the age of mobile ammonia/ammonium is observed after installing tile drains. This is in contrast to the cases for nitrate, immobile ammonium, and nonreactive tracer. These results arise because the depletion of mobile ammonia/ammonium due to tile drainage causes a high mobility flux from immobile ammonium to mobile ammonia/ammonium, which also carries a considerable amount of relatively old age of nitrogen from immobile ammonium to mobile ammonia/ammonium. These results illustrate how storm event scale dynamics impact spatial heterogeneity and temporal variability of the efflux, which helps in disentangling the complexity of nitrogen dynamics in the soil. This understanding can contribute to precision agriculture for nitrogen applications to reduce environmental impacts.