Title: Field-to-farm gate greenhouse gas emissions from corn stover production in the Midwestern U.S.

Abstract

Measured field data were used to compare two allocation methods on life cycle greenhouse gas emissions from corn (Zea mays L.) stover production in the Midwest U.S. We used publicly-available crop yield, nitrogen fertilizer, and direct soil nitrous oxide emissions data from the USDA-ARS Resilient Economic Agricultural Practices research program. Field data were aggregated from 9 locations across 26 site-years for 3 stover harvest rates (no removal; moderate removal – 3.1 Mg ha^–1; high removal – 7.2 Mg ha^–1) and 2 tillage practices (conventional; reduced/no-till). Net carbon uptake by crops was computed from measured plant carbon content. Monte Carlo simulations sampled input distributions to assess variability in farm-to-gate GHG emissions. The base analysis assumed no change in soil organic carbon stocks. In all cases, net CO₂ uptake during crop growth and soil-respired CO₂ dominated system emissions. Emissions were most sensitive to co-product accounting method, with system expansion emissions ~15% lower than mass allocation. Regardless of accounting method, lowest emissions occurred for a moderate removal rate under reduced/no-till management. The absence of correlations between N fertilization rate and stover removal rate or soil N₂O emissions in this study challenges the use of such assumptions typically employed in life cycle assessments Storagemore » of all carbon retained on the field as SOC could reduce emissions by an additional 15%. Furthermore, our results highlight how variability in GHG emissions due to location and weather can overshadow the impact of farm management practices on field-to-farm gate emissions. Graphical abstract« less

Authors:

Locker, C. Rebecca ^[1]; Torkamani, Sarah ^[1]; Laurenzi, Ian J. ^[1]; Jin, Virginia L. ^[2]; Schmer, Marty R. ^[2]; Karlen, Douglas L. ^[3]

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+ Show Author Affiliations

1. ExxonMobil Research and Engineering Company, Annandale, NJ (United States)
2. Univ. of Nebraska, Lincoln, NE (United States)
3. National Lab. for Agriculture and the Environment (NLAE), Ames, IA (United States)

Publication Date:

Thu Mar 28 00:00:00 EDT 2019

Research Org.:

Antares Group Inc., Conyers, GA (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE), Transportation Office. Bioenergy Technologies Office

OSTI Identifier:

1853970

Report Number(s):

DOE-ANTARES-07088-2-6
Journal ID: ISSN 0959-6526

Grant/Contract Number:  

EE0007088

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Cleaner Production

Additional Journal Information:

Journal Volume: 226; Journal ID: ISSN 0959-6526

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; Life-cycle assessment; Corn stover; Greenhouse gases; Bioenergy; Biofuel