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ARS Home » Plains Area » Sidney, Montana » Northern Plains Agricultural Research Laboratory » Agricultural Systems Research » Research » Publications at this Location » Publication #295180

Title: Net global warming potential and greenhouse gas intensity influenced by irrigation, tillage, crop rotation, and nitrogen fertilization

Author
item Sainju, Upendra
item Stevens, William - Bart
item Caesar, Thecan
item Liebig, Mark
item Wang, Jun - Northwest Agriculture And Forestry University

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2013
Publication Date: 5/9/2014
Publication URL: http://handle.nal.usda.gov/10113/58408
Citation: Sainju, U.M., Stevens, W.B., Caesar, T., Liebig, M.A., Wang, J. 2014. Net global warming potential and greenhouse gas intensity influenced by irrigation, tillage, crop rotation, and nitrogen fertilization. Journal of Environmental Quality. 43(3):777–788.

Interpretive Summary: Life-cycle analysis of greenhouse gas emissions from agroecosystems involves accounting of all sources and sinks of carbon cost (or CO2 equivalents) from farm operations, soil carbon sequestration, crop residue returned to the soil and greenhouse gas emissions. Little is known about sources and sinks of greenhouse gases (GHGs) as affected by management practices to account for net emissions from agroecosystems. We evaluated the effects of irrigation, tillage, crop rotation, and N fertilization on net global warming potential (GWP) and greenhouse gas intensity (GHGI) after accounting for CO2 emissions from all sources (irrigation, farm operations, N fertilization, and soil GHG fluxes) and sinks (crop residue and soil C sequestration) in a Lihen sandy loam from 2008 to 2011 in western North Dakota. Treatments were two irrigation practices (irrigated vs. non-irrigated) and five cropping systems (conventional-till malt barley with N fertilizer [CTBN], conventional-till malt barley with no N fertilizer [CTBO], no-till malt barley-pea with N fertilizer [NTB-P], no-till malt barley with N fertilizer [NTBN], and no-till malt barley with no N fertilizer [NTBO]). While CO2 equivalents were greater with irrigation, tillage, and N fertilization than without, equivalents of N2O and CH4 fluxes were greater in non-irrigated NTBN and irrigated CTBN, respectively, than most other treatments. Previous year’s crop residue returned to the soil and C sequestration rate were greater in irrigated NTB-P, but grain yield was greater in irrigated CTBN than other treatments. Net GWP and GHGI based on soil respiration and organic C (SOC) were lower in NTB-P than other treatments, regardless of irrigation. Because of lower GHG emissions, NTB-P may be used as a management option to reduce net GHG emissions from agroecosystems compared to conventional CTBN in the northern Great Plains. This management option can also sustain grain yields, reduce the amount of N fertilizer, and control weeds, pests, and diseases better than CTBN.

Technical Abstract: Little information exists about sources and sinks of greenhouse gases (GHGs) affected by management practices to account for net emissions from agroecosystems. We evaluated the effects of irrigation, tillage, crop rotation, and N fertilization on net global warming potential (GWP) and greenhouse gas intensity (GHGI) after accounting for CO2 emissions from all sources (irrigation, farm operations, N fertilization, and soil GHG fluxes) and sinks (crop residue and soil C sequestration) in a Lihen sandy loam from 2008 to 2011 in western North Dakota. Treatments were two irrigation practices (irrigated vs. non-irrigated) and five cropping systems (conventional-till malt barley [Hordeum vulgaris L.] with N fertilizer [CTBN], conventional-till malt barley with no N fertilizer [CTBO], no-till malt barley-pea [Pisum sativum L.] with N fertilizer [NTB-P], no-till malt barley with N fertilizer [NTBN], and no-till malt barley with no N fertilizer [NTBO]). While CO2 equivalents were greater with irrigation, tillage, and N fertilization than without, equivalents of N2O and CH4 fluxes were greater in non-irrigated NTBN and irrigated CTBN, respectively, than most other treatments. Previous year’s crop residue returned to the soil and C sequestration rate were greater in irrigated NTB-P, but grain yield was greater in irrigated CTBN than other treatments. Net GWP and GHGI based on soil respiration and organic C (SOC) were lower in NTB-P than other treatments, regardless of irrigation. As a result, NTB-P may be used as a management option to reduce net GHG emissions from agroecosystems compared to conventional CTBN in the northern Great Plains.