Soil greenhouse gas emissions in response to corn stover removal and tillage management across the US corn belt

Authors: Jin, Virginia; Baker, John; Johnson, Jane; Karlen, Douglas; Lehman, R - Michael; Osborne, Shannon; Sauer, Thomas; Stott, Diane; Varvel, Gary; Venterea, Rodney - Rod; Schmer, Marty; Wienhold, Brian

Submitted to: BioEnergy Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/15/2014
Publication Date: 2/4/2014
Publication URL: http://handle.nal.usda.gov/10113/58944
Citation: Jin, V.L., Baker, J.M., Johnson, J.M., Karlen, D.L., Lehman, R.M., Osborne, S.L., Sauer, T.J., Stott, D.E., Varvel, G.E., Venterea, R.T., Schmer, M.R., Wienhold, B.J. 2014. Soil greenhouse gas emissions in response to corn stover removal and tillage management across the US corn belt. BioEnergy Research. 7(2):517-527. DOI: 10.1007/S12155-014-9421-0.

Interpretive Summary: Corn stover is the plant material left on the field after harvesting corn grain. Stover and other crop residues in the U.S. Corn Belt are considered a major source for supplying the Nation’s developing second generation biofuels industry. Removal of corn stover from farm land, however, leaves soil vulnerable to water and wind erosion. Stover removal also decreases the return of plant materials into the soil to support long-term soil fertility and crop productivity. Economic and environmental assessments of the emerging second generation biofuel industry are usually modeled, and field measurements are needed to check model estimates. The emission of greenhouse gases from the soil is an important part of these assessments. Field measurements from many locations and over many years are needed to verify modeled emissions values. This study summarizes soil greenhouse gas emissions for a five-year, multi-location research project in the U.S. Corn Belt. Results show that soil greenhouse gas emissions can be decreased when stover is removed, especially if soils are managed with no tillage or reduced tillage conservation practices.

Technical Abstract: In-field measurements of direct soil greenhouse gas (GHG) emissions provide critical data for quantifying the net energy efficiency and economic feasibility of crop residue-based bioenergy production systems. A major challenge to such assessments has been the paucity of field studies addressing the effects of crop residue removal and associated best practices for soil management (i.e., conservation tillage) on soil emissions of carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4). This regional survey summarizes soil GHG emissions from nine maize production systems evaluating different levels of corn stover removal under conventional or conservation tillage management across the US Corn Belt. Cumulative growing season soil emissions of CO2, N2O, and/or CH4 were measured for 2–5 years (2008–2012) at these various sites using a standardized static vented chamber technique as part of the USDA-ARS’s Resilient Economic Agricultural Practices (REAP) regional partnership. Cumulative soil GHG emissions during the growing season varied widely across sites, by management, and by year. Overall, corn stover removal decreased soil total CO2 and N2O emissions by -4 and -7 %, respectively, relative to no removal. No management treatments affected soil CH4 fluxes. When aggregated to total GHG emissions (Mg CO2'eq ha-1) across all sites and years, corn stover removal decreased growing season soil emissions by -5'±'1 % (mean'±'se) and ranged from -36 % to 54 % (n'='50). Lower GHG emissions in stover removal treatments were attributed to decreased C and N inputs into soils, as well as possible microclimatic differences associated with changes in soil cover. High levels of spatial and temporal variabilities in direct GHG emissions highlighted the importance of site-specific management and environmental conditions on the dynamics of GHG emissions from agricultural soils.