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Nitrous oxide, methane emission, and yield-scaled emission from organically and conventionally managed systems
- Empirical data on methane (CH4) and nitrous oxide (N2O) emission are needed for management systems from many regions of the United States to evaluate mitigation strategies. The primary objectives of this study were to assess and compare crop productivity, CH4 andN2O flux, and yield-scaled emissions between a conventionally and an organically managed system. All phases of a corn (Zea mays L.)–soybean [Glycine max L. (Merr.)]–wheat (Triticum aestivum L.) over alfalfa (Medicago sativa L.)–alfalfa rotation were present each year. Both systems emitted about 4.2 kg N2O-N ha−1 yr−1 including growing and nongrowing season emissions, which cumulatively represents 4.74 and 9.26% of 267 kg synthetic-N and 136 kg manure-N applied, respectively. The equivalent of 0.84% of the 78 kg urea-N and 0.76% of the 136 kg manure-N were emitted as N2O ha−1 within 30-d of fertilizer application in the conventionally managed system and organically managed system, respectively. Following the application of starter fertilizer to the conventionally managed corn, the equivalent of 3.45% of the 11 kg starter N was emitted within 30 d. The largest spring-thaw N2O flux was measured in the conventionally managed system following alfalfa, which had been killed the previous fall. Yield-scaled N2O+CH4 emission (Mg CO2 equivalents Mg−1 yield) was 1.6- to 5-times greater in the organically managed system, which had lower yield but similar emission compared to the conventionally managed system. Thus, viability of organic systems to mitigate greenhouse gas (GHG) emission may be compromised when crop productivity is reduced. Study results highlight the importance of assessing emission and crop production when evaluating GHG mitigation strategies.
Johnson, Jane M.F. , Weyers, Sharon L. , Archer, David W. , Barbour, Nancy W.
Glycine max , Medicago sativa , Triticum aestivum , Zea mays , alfalfa , carbon dioxide , corn , crop production , fertilizer application , greenhouse gas emissions , greenhouse gases , growing season , methane , methane production , nitrous oxide , organic production , traditional farming , United States
- Includes references
- Soil Science Society of America journal 2012 July, v. 76, no. 4
Journal Articles, USDA Authors, Peer-Reviewed
- Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.