Nitrous Oxide Fluxes from Agricultural Streams in East-Central Illinois
Indirect nitrous oxide (N2O) emissions account for the majority of uncertainty associated with the global N2O budget. Agricultural streams with subsurface (tile) drainage are potential hotspots of indirect N2O emissions from streams and groundwater. However, there are only a limited number of studies with direct measurements from stream surfaces. Research presented here represents the first study of N2O emissions from agricultural streams in Illinois, USA. We measured water chemistry data from 10 sites in three watersheds in east-central Illinois. Additionally, floating chambers and gas transfer velocity models were used to measure N2O fluxes from the stream surface at 4 of the 10 sites. Dissolved N2O concentrations ranged from < 0.1 to 7.46 μg N2O-N L−1. Floating chamber N2O fluxes ranged from 0 to 13.84 μg N2O-N m−2 min−1. We found strikingly different patterns of nitrate (NO3−) concentrations at sites downstream of a wastewater treatment plant (WWTP) effluent. Data from sites not affected by the WWTP expressed seasonal variations of NO3− with elevated concentrations in winter and spring months when subsurface tile drains were flowing. Floating chamber N2O fluxes were strongly correlated (p value 0.001) with NO3− at sites not affected by the WWTP. All sites were correlated with flow (p value 0.01) and dissolved N2O (p value 0.02). Our data suggest flow and dissolved N2O are stronger indicators of N2O flux from stream surfaces than NO3− concentrations in agricultural watersheds. Furthermore, this study supports growing concerns of estimating N2O emissions using linear relationships between N2O and NO3−, such as those used in IPCC estimates.
KeywordsNitrous oxide Indirect emissions Streams Tile drainage Water quality Greenhouse gas emissions
We thank Candice Smith for field and laboratory work along with data compilation, Corey Mitchell for laboratory analysis and data summaries, and Ryland French and Lauren Behnke for sample collection. This work was partially funded by the Energy Biosciences Institute and the United States Department of Agriculture National Institute of Food and Agriculture under agreement no. 2009-51130-06041.
- David, M. M. B., Gentry, L. L. E., Kovacic, D. a., & Smith, K. M. K. (1997). Nitrogen balance in and export from an agricultural watershed. Journal of Environmental Quality, 26(4), 1038–1048. https://doi.org/10.2134/jeq1997.00472425002600040015x.CrossRefGoogle Scholar
- Dong, L. F., Nedwell, D. B., Colbeck, I., & Finch, J. (2004). Rivers and estuaries, (1998), pp. 127–134.Google Scholar
- Hudson, F. (2004). Sample preparation and calculations for dissolved gas analysis in water samples using a GC headspace equilibration technique. RSKSOP-175 v.2. http://www.epa.gov/region1/info/testmethods/. Accessed 10 Mar 2018.
- Intergovernmental Panel on Climate Change (2006). N2O emissions from managed soils,and urea application. 2006 IPCC Guidelines for National Greenhouse Gas Inventories Volume 4: Agriculture, Forestry and Other Land Use, 11.1–11.54. http://www.ipcc-nggip.iges.or.jp/public/2006gl/pdf/4_Volume4/V4_11_Ch11_N2O&CO2.pdf
- Lorke, A., Bodmer, P., Noss, C., Alshboul, Z., Koschorreck, M., Somlai-Haase, C., et al. (2015). Technical note: Drifting versus anchored flux chambers for measuring greenhouse gas emissions from running waters. Biogeosciences, 12(23), 7013–7024. https://doi.org/10.5194/bg-12-7013-2015.CrossRefGoogle Scholar
- Myhre, G., Shindell, D., Bréon, F.-M., Collins, W., Fuglestvedt, J., Huang, J., et al. (2013). Anthropogenic and natural radiative forcing. Climate change 2013: The physical science basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, 659–740. https://doi.org/10.1017/CBO9781107415324.018.
- Smith, C. M., David, M. B., Mitchell, C. A., Masters, M. D., Anderson-Teixeira, K. J., Bernacchi, C. J., & Delucia, E. H. (2013). Reduced nitrogen losses after conversion of row crop agriculture to perennial biofuel crops. Journal of Environmental Quality, 42(1), 219–228. https://doi.org/10.2134/jeq2012.0210.CrossRefGoogle Scholar
- Stow, C. A., Walker, J. T., Cardoch, L., Spence, P., & Geron, C. (2005). N2O emissions from streams in the Neuse River watershed, North Carolina, 39(18), 6999–7004.Google Scholar
- Turner, P. A., Griffis, T. J., Lee, X., Baker, J. M., Venterea, R. T., & Wood, J. D. (2015). Indirect nitrous oxide emissions from streams within the US Corn Belt scale with stream order. Proceedings of the National Academy of Sciences, 112(32), 9839–9843. https://doi.org/10.1073/pnas.1503598112.CrossRefGoogle Scholar
- Turner, P. A., Griffis, T. J., Baker, J. M., Lee, X., Crawford, J. T., Loken, L. C., & Venterea, R. T. (2016). Regional-scale controls on dissolved nitrous oxide in the Upper Mississippi River. Geophysical Research Letters, 43(9), 4400–4407. https://doi.org/10.1002/2016GL068710.CrossRefGoogle Scholar