Open AccessNitrogen fertilizer and landscape position impacts on CO 2 and CH 4 fluxes from a landscape seeded to switchgrass
Author(s) -
Mbonimpa Eric G.,
Hong Chang O.,
Owens Vance N.,
Lehman R. Michael,
Osborne Shan L.,
Schumacher Thomas E.,
Clay David E.,
Kumar Sandeep
Publication year - 2015
Publication title -
gcb bioenergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.378
H-Index - 63
eISSN - 1757-1707
pISSN - 1757-1693
DOI - 10.1111/gcbb.12187
Subject(s) - panicum virgatum , environmental science , fertilizer , carbon dioxide , agronomy , nitrogen , soil carbon , zoology , chemistry , soil water , soil science , ecology , bioenergy , biology , biofuel , organic chemistry
This study was conducted to evaluate the impacts of N fertilizer and landscape position on carbon dioxide ( CO 2 ) and methane ( CH 4 ) fluxes from a US Northern Great Plains landscape seeded to switchgrass ( Panicum virgatum L.). The experimental design included three N levels (low, 0 kg N ha −1 ; medium, 56 kg N ha −1 ; and high, 112 kg N ha −1 ) replicated four times. The experiment was repeated at shoulder and footslope positions. Soil CO 2 and CH 4 fluxes were monitored once every 2 weeks from May 2010 to October 2012. The CO 2 fluxes were 40% higher at the footslope than the shoulder landscape position, and CH 4 fluxes were similar in both landscape positions. Soil CO 2 and CH 4 fluxes averaged over the sampling dates were not impacted by N rates. Seasonal variations showed highest CO 2 release and CH 4 uptake in summer and fall, likely due to warmer and moist soil conditions. Higher CH 4 release was observed in winter possibly due to increased anaerobic conditions. However, year to year (2010–2012) variations in soil CO 2 and CH 4 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 2 fluxes (between 1.3 and 3 times) than in 2011 and 2010. These conditions also promoted a net CH 4 uptake in 2012 in comparison to 2010 when there was net CH 4 release. Results from this study conclude that landscape positions, air temperature, and soil moisture content strongly influenced soil CO 2 fluxes, whereas soil moisture impacted the direction of CH 4 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.