Thesis
Magnitude and timing of stream nitrate export in a semi-arid dryland agricultural watershed
Washington State University
Master of Science (MS), Washington State University
2013
Handle:
https://hdl.handle.net/2376/103491
Abstract
Missouri Flat Creek (MFC) is located in the Palouse region, a rain-fed agricultural region with highly seasonal discharge. High flows occur primarily during the winter (December-April). A 10-year record of nitrate concentrations and water discharge for three locations along MFC is used to examine nitrate mass discharge and areal flux. During high winter flow events, a decrease in NO3 - -N concentrations is observed in the downstream direction, and is attributed to dilution. Factors controlling dilution in the region are not fully understood, but may be due to heterogeneous land use within the basin or hydrologic controls. During the summer, decreases in mass discharge in the downstream direction are likely indicative of biological uptake within the stream channel. However, the magnitude of biological uptake is small compared with winter export of nitrate. High winter flows export the majority (75-99%) of the total annual load of nitrate, and single flood events may export up to 10% of the nitrogen fertilizer applied annually. Given that most of the annually exported NO3 - -N is moving during the winter, when low light availability and cold temperatures limit biological uptake, increasing on-field retention is important to decrease the amount of annual exported nitrogen from agricultural land in this region.
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Details
- Title
- Magnitude and timing of stream nitrate export in a semi-arid dryland agricultural watershed
- Creators
- Julia Schwarz
- Contributors
- Cailin Huyck Orr (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Environment, School of the (CAHNRS)
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525120701842
- Language
- English
- Resource Type
- Thesis