@article{Vidon_Hubbard_Cuadra_Hennessy_2012, title={Storm NO<sub;>3</sub><sup>-</sup> and NH<sub;>4</sub><sup>+</sup> Exports in Stream, Overland Flow, and Tile Drains of the US Midwest}, volume={6}, url={https://openjournals.neu.edu/aes/journal/article/view/v6art5}, abstractNote={&lt;p&gt;A better understanding of the dynamics of nitrogen (N) losses to streams during storms in agro-ecosystems of the US Midwest is critical to better understand how to mitigate N pollution in the Mississippi River Basin. This study investigates storm NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; and NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt; concentrations and fluxes in tile drains, overland flow and stream water in relation to bulk precipitation and antecedent moisture conditions. For moderate size spring storms (1.0 - 4.5 cm bulk precipitation), the occurrence of overland flow was primarily associated with high antecedent moisture conditions, but had no direct effect on stream NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; and NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt; concentrations. Mean storm NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; and NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt; concentrations in the stream and tile drains were also not significantly correlated (p &gt; 0.05) to either bulk precipitation or antecedent moisture conditions. Nevertheless, mean stream NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; concentrations (7.50 mg N/L) were on average 28% lower than in tile drains (10.38 mg N/L). No significant difference in NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+ &lt;/sup&gt;concentrations were observed between the stream (0.06 mg N/L) and tile drains (0.05 mg N/L). NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; and NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+ &lt;/sup&gt;fluxes were positively correlated with bulk precipitation (p &lt; 0.05) and high fluxes were typically associated with wet antecedent moisture conditions. Specific NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; fluxes in tile drains (750 g N/ha/storm) were approximately 2 times larger than in the stream (398 g N/ha/storm). Such differences were not observed for NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+ &lt;/sup&gt;fluxes. Considering the positive correlation between storm NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; fluxes and stream NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; baseflow concentrations (r = 0.87, p &lt; 0.05), it is likely that one of the most efficient strategies for reducing N losses at the watershed scale may simply lie in reducing N inputs to cropland, as opposed to trying to manage N after it is applied to fields.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Permanent URL: &lt;/strong&gt;&lt;a href=&quot;http://hdl.handle.net/2047/d20002606&quot;&gt;http://hdl.handle.net/2047/d20002606&lt;/a&gt;&lt;/p&gt;}, journal={Annals of Environmental Science}, author={Vidon, Philippe and Hubbard, Hilary and Cuadra, Pilar and Hennessy, Matthew}, year={2012}, month={Sep.} }