|VAN SCOYOC, G|
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2009
Publication Date: 5/1/2009
Citation: Hernandez-Ramirez, G., Brouder, S.M., Smith, D.R., Van Scoyoc, G., Filley, T.R. 2009. Greenhouse gas fluxes in an Eastern Corn Belt soil: Weather, nitrogen source and rotation. Journal of Environmental Quality. 38:841-854.
Interpretive Summary: The relative contribution of diverse agroecosystems to the greenhouse gas effect is not completely documented. This study was conducted to estimate soil surface fluxes of carbon dioxide, methane, nitrous oxide, and global warming potential as affect by management and weather. The cropping systems evaluated were continuous corn, corn-soybean rotation or restored prarie grass. The nitrogen fertilizer sources for corn were an inorganic fertilizer (urea ammonium nitrate) or swine manure applied in the spring or in the fall. Carbon dioxide fluxes correlated with soil temperature and the total rainfall that occurred within the previous 5 days. Carbon dioxide emissions represented the greatest volume of gas emissions from soils, and thus accounted for 85% of the global warming potential from these soils. Soils that received manure emitted methane to the atmosphere, whereas the soils scrubbed methane from the atmosphere when they were cropped using inorganic fertilizers. Pulse emissions of nitrous oxide after fertilization and rainfall events regulated annual or seasonal nitrous oxide emissions. The impact of this research is to inform producers, policy makers and other scientists about greenhouse gas emissions from soils in the Eastern Corn-Belt as affected by cropping systems management.
Technical Abstract: The relative contribution of diverse agroecosystems to the greenhouse gas effect is not completely documented. This study was conducted to estimate soil surface fluxes of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and global warming potential (GWP) as affect by management and weather. Gas fluxes were measured by vented, static chambers in Drummer and Raub soil series during two growing seasons evaluating continuous corn (CCUAN) and corn-soybean rotation (CSUAN) both with urea-ammonium nitrate, continuous corn with either spring (CCSM) or fall liquid swine manure (CCFM), soybean (SC, grown in the CSUAN), and restored prairie grass (PG). The CO2 fluxes were correlated with soil temperature and accumulated rainfall 120 hours prior to sampling, and N2O fluxes with soil temperature. Seasonal CO2 emissions and GWP were typically not different across treatments (4.4 and 5.2 Mg CO2-C ha-1 yr-1, respectively), but differed between the years. Soil receiving manure CCSM and CCFM were net seasonal CH4 emitters, whereas CSUAN and CCUAN recorded CH4 uptake. Seasonal N2O emissions were extremely different across treatments and they were mainly driven by pulse emissions after N fertilizer inputs in concurrence with major rainfall events. The results suggest that fall manure application, corn-soybean rotation, and restoration of prairie grass may diminish N2O emissions and hence might contribute to GWP mitigation.