The impact of fertilization and hydrology on nitrate fluxes from Mississippi watersheds
The impact of fertilization and hydrology on nitrate fluxes from Mississippi watersheds
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DOI：
10.1016/j.cosust.2012.04.001
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发表时间：
2012-05
影响因子：
7.2
通讯作者：
P. Raymond;M. David;J. Saiers
中科院分区：
文献类型：
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作者：
P. Raymond;M. David;J. Saiers
密西西比河流域是世界上管理最密集的农业流域之一。因此，它们接受高负荷的氮，并将大量硝酸盐输出到密西西比河流域和沿海海洋的排水网络中。我们发现化肥投入与氮素径流输出之间存在正相关关系。根据相关性，∼34%的肥料氮出口到密西西比盆地的小溪和河流，这一比例高于全球平均水平。这种关系在一定程度上是因果关系，但也反映了间接影响，因为密西西比盆地的化肥使用也与农业实践有关，如行作物和瓷砖排水。这些农业措施的总体影响是增加水的吞吐量，减少水和氮的停留时间和加工，这反过来又增加了氮的出口和肥料出口的百分比。这一反应，加上中西部降水量普遍增加，正在加剧氮问题，并将降低减氮管理的效力。
The watersheds of the Mississippi are some of the most intensively managed agricultural basins in the world. As such, they receive high loadings of nitrogen and export a large amount of nitrate to the drainage networks of the Mississippi River basin and coastal ocean. We find a positive correlation between fertilizer input and stream export of nitrogen. According to the correlation, ∼34% of applied fertilizer nitrogen is exported to streams and rivers of the Mississippi basin, a fraction that is greater than the global average. The relationship is partly causal, but also reflects indirect effects, as fertilizer application in the Mississippi basin also correlates with agricultural practices, such as row cropping and tile drainage. The overall impact of these agricultural practices is to increase water throughput and decrease water and nitrogen residence time and processing, which, in turn, increase nitrogen export and the percentage of fertilizer that is exported. This response, coupled with a general increase in precipitation in the Mid-West, is exacerbating the nitrogen problem and will decrease the efficacy of nitrogen-reduction management.