Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/1/2008
Publication Date: 2/19/2009
Citation: Ogle, S.M., Del Grosso, S.J. , Adler, P.R. , Parton, W.J. . 2008. Soil nitrous oxide emissions with crop production for biofuel: Implications for greenhouse gas mitigation. In: J.L. Outlaw and D.P. Ernstes (Eds.). The Lifecycle Carbon Footprint of Biofuels, Farm Foundation, Oak Brook, IL. p. 11-18. Interpretive Summary: An interpretive summary is not required.
Technical Abstract: The growing biofuel commodity market for corn ethanol has the potential to reduce direct greenhouse gas (GHG) emissions associated with fossil fuel combustion in the US. However, projected increases in cropland to accommodate this energy-based commodity will also impact emissions of GHGs from soils. In the recent past, US agricultural soils have been a net sink for atmospheric CO2, largely due to the enrollment of land in Conservation Reserve Program (CRP). Conversion of formerly enrolled lands into biofuel production seems likely with a large portion of contracts ending in the next 5 years. This will lead to a release of CO2 from soils that had been sequestered during recent decades, although losses may be limited with no-till management. In addition to the effect on soil C, fertilization on former CRP lands will also increase soil N2O emissions. Furthermore, corn production is likely to increase on lands currently used for other crops or crops grown in rotation with corn, such as soybeans. Corn is often fertilized more than other crops, and this will lead to additional increases in soil N2O emissions. GHG emissions from soils due to the growing biofuel commodity market will reduce some of the benefit of this energy crop for mitigation of GHG emissions, but the net benefit may still be positive depending on the amount of the total emissions from the production system, including production of chemical inputs and transportation, and the offset of emissions by reducing fossil fuel combustion.