Nitrogen fertilizer and landscape position impacts on CO2 and CH4 fluxes from a landscape seeded to switchgrass. Issue 4 (29th April 2014)

• Record Type: Journal Article
• Authors: Mbonimpa, Eric G.; Hong, Chang O.; Owens, Vance N.; Lehman, R. Michael; Osborne, Shannon L.; Schumacher, Thomas E.; Clay, David E.; Kumar, Sandeep
• Is Part Of: Global change biology. Volume 7:Issue 4(2015)
• Page Start: 836
• Page End: 849
• Publication Date: 2014-04-29
• Subjects: Biomass energy -- Periodicals; Biomass energy -- Environmental aspects -- Periodicals; Energy crops -- Periodicals; 662.88
• DOI: 10.1111/gcbb.12187
• Languages: English
• ISSNs: 1757-1693

Abstract

<abstract abstract-type="main" id="gcbb12187-abs-0001"> <title>Abstract</title> <p>This study was conducted to evaluate the impacts of N fertilizer and landscape position on carbon dioxide (CO<sub>2</sub>) and methane (CH<sub>4</sub>) fluxes from a US Northern Great Plains landscape seeded to switchgrass (<italic>Panicum virgatum</italic> L.). The experimental design included three N levels (low, 0 kg N ha<sup>−1</sup>; medium, 56 kg N ha<sup>−1</sup>; and high, 112 kg N ha<sup>−1</sup>) replicated four times. The experiment was repeated at shoulder and footslope positions. Soil CO<sub>2</sub> and CH<sub>4</sub> fluxes were monitored once every 2 weeks from May 2010 to October 2012. The CO<sub>2</sub> fluxes were 40% higher at the footslope than the shoulder landscape position, and CH<sub>4</sub> fluxes were similar in both landscape positions. Soil CO<sub>2</sub> and CH<sub>4</sub> fluxes averaged over the sampling dates were not impacted by N rates. Seasonal variations showed highest CO<sub>2</sub> release and CH<sub>4</sub> uptake in summer and fall, likely due to warmer and moist soil conditions. Higher CH<sub>4</sub> release was observed in winter possibly due to increased anaerobic conditions. However, year to year (2010–2012) variations in soil CO<sub>2</sub> and CH<sub>4</sub> fluxes were more pronounced than the variations due to the impact of landscape positions and N rates. Drought conditions reported in 2012, with higher annual temperature and lower soil moisture than long‐term average, resulted in higher summer and fall CO<sub>2</sub> fluxes (between 1.3 and 3 times) than in 2011 and 2010. These conditions also promoted a net CH<sub>4</sub> uptake in 2012 in comparison to 2010 when there was net CH<sub>4</sub> release. Results from this study conclude that landscape positions, air temperature, and soil moisture content strongly influenced soil CO<sub>2</sub> fluxes, whereas soil moisture impacted the direction of CH<sub>4</sub> fluxes (uptake or release). However, a comprehensive life cycle analysis would be appropriate to evaluate environmental impacts associated with switchgrass production under local environmental conditions.</p> </abstract>