ARS | Publication request: Management to reduce greenhouse gas emissions in western U.S. croplands

Submitted to: Elsevier
Publication Type: Book / Chapter
Publication Acceptance Date: July 6, 2011
Publication Date: June 19, 2012
Citation: Halvorson, A.D., Steenwerth, K.L., Suddick, E.C., Liebig, M.A., Smith, J.L., Bronson, K.F., Collins, H.P. 2012. Management to reduce greenhouse gas emissions in western U.S. croplands. Elsevier. New York, NY: Elsevier Inc. p. 167-182.

Interpretive Summary: Literature from 2005-2011 on greenhouse gas (GHG) emissions (CO2, CH4, N2O) from crop production systems in the Western U.S. was reviewed to determine potential GHG mitigation options. GHG emissions data from cropping systems was limited. Converting from conventional tillage (CT) to minimum-till (MT) or no-till (NT) production to sequester soil organic carbon (SOC), reduces CO2 emissions in some cropping systems, but not all. Methane emissions or uptake are not greatly influenced by crop management practices, except in rice and manure production systems. N2O emissions are affected by N availability, climatic factors, irrigation, and crop management practices. N2O emissions tend to be lower under dryland than irrigated cropping conditions. Inorganic N fertilizer source and rate affect N2O emissions. Micro jet sprinkler and subsurface drip irrigation reduces N2O emissions compared to surface drip irrigation. Available GHG data can be used to verify GHG prediction models and develop local mitigation practices, but due to diversity of cropping systems, climates, soils, and lack of representative cropping system GHG data bases, generalized mitigation practices for the Western U.S. is probably not feasible.

Technical Abstract: Greenhouse gas (GHG) emissions (CO2, CH4, N2O) research from crop production systems in the Western U.S. published from 2005-2011 is summarized here. Limited GHG emissions data were found. Data from irrigated cropping systems in California (grain, rice, vegetable, orchards), Texas (cotton), Colorado (corn), and Washington (corn and potato), and from dryland wheat systems in Montana and North Dakota were found. Converting from conventional tillage (CT) to minimum-till (MT) or no-till (NT) production to sequester SOC, reduces CO2 emissions in some cropping systems, but not all. Methane emissions or uptake are not greatly influenced by crop management practices, except in rice and manure production systems. Nitrous oxide (N2O) emissions are affected by N availability, climatic factors, irrigation, and crop management practices. N2O emissions tend to be lower under dryland than irrigated cropping conditions. Reducing N fertilization rate and selecting the right N source can reduce N2O emissions. Use of micro-jet sprinkler or subsurface drip irrigation can reduce N2O emissions in vineyards and orchards. Available GHG data could be used to verify GHG prediction models and develop local mitigation practices, but due to diversity of cropping systems, climates, soils, and lack of representative cropping system GHG data bases, generalized mitigation practices for the Western U.S. is probably not feasible.