Location: Agricultural Systems ResearchTitle: Life-cycle analysis of dryland greenhouse gases affected by cropping sequence and nitrogen fertilization
Submitted to: World Congress of Soil Science
Publication Type: Abstract Only
Publication Acceptance Date: 2/15/2014
Publication Date: N/A
Technical Abstract: Little information is available about management practices effect on net global warming potential (GWP) and greenhouse gas intensity (GHGI) under dryland cropping systems. We evaluated the effects of cropping sequences (conventional till malt barley-fallow [CTB-F], no-till malt barley-pea [NTB-P], and no-till continuous malt barley [NTCB]) and N fertilization rates (0 and 80 kg N ha-1) on net GWP and GHGI from 2008 to 2011 in eastern Montana. The CO2 equivalent from farm operations was greater in CTB-F than NTB-P and NTCB, from N fertilization was greater with 80 than with 0 kg N ha-1, and from crop residue and soil organic C (SOC) sequestration were greater in NTB-P or NTCB with 80 kg N ha-1 than other treatments, but the equivalent from soil greenhouse gases (GHGs) varied among treatments and years. Net GWP and GHGI based on soil respiration were greater in NTCB with 0 kg N ha-1, but GWP and GHGI based on SOC were greater in CTB-F with 0 kg N ha-1 than other treatments. Because of greater grain yield but lower GWP and GHGI, NTB-P with 80 kg N ha-1 may be used as a management option to reduce global warming potential while sustaining dryland crop yields compared to CTB-F with 0 kg N ha-1 in the northern Great Plains. The management option also has been known to reduce the cost of N fertilization and control weeds, pests, and diseases effectively compared to NTCB with 80 kg N ha-1.