Iowa Geological and Water Survey, 109 Trowbridge Hall, Iowa City, IA, 52242-1319, USA,
Environ Manage. 2013 Dec;52(6):1440-52. doi: 10.1007/s00267-013-0142-5. Epub 2013 Aug 24.
In this paper, we argue that there is tremendous potential for nitrate-N reductions to occur throughout the Corn Belt region of the USA if we simply let naturally occurring wet spots on the landscape be wet. Geologic and hydrologic data gathered in the Walnut Creek watershed located in south-central Iowa provides compelling evidence that substantial nutrient-processing capacity exists in this dissected glacial landscape. Self-similarity of stratigraphy, sedimentology and hydrology observed at all spatial scales in the watershed suggests that Holocene alluvial fill deposits provide a natural bioreactor for denitrification of upland groundwater nitrate-N; the occurrence of such deposits can be mapped to identify potential nitrogen sinks across the landscape. This approach to identifying potential nitrogen sinks is geology focused and extends potential locations for nutrient processing upstream into the headwater catchments of individual fields.
本文认为，如果我们让景观中原有的湿地保持湿润，那么美国玉米带地区的硝酸盐氮就有很大的减少潜力。在爱荷华州中南部的沃尔纳特溪流域收集的地质和水文学数据提供了令人信服的证据，表明在这个被分割的冰川地貌中存在大量的养分处理能力。流域内所有空间尺度上的地层结构、沉积学和水文学的自相似性表明，全新世冲积物为高地地下水硝酸盐氮的反硝化提供了一个自然的生物反应器；这样的沉积物的出现可以被绘制出来，以确定景观中潜在的氮汇。这种识别潜在氮汇的方法侧重于地质学，并将养分处理的潜在位置向上游延伸到各个农田的源头集水区。
