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ARS Home » Plains Area » Sidney, Montana » Northern Plains Agricultural Research Laboratory » Agricultural Systems Research » Research » Publications at this Location » Publication #304538

Research Project: Development of Ecologically-Sound Pest, Water and Soil Management Practices for Northern Great Plains Cropping Systems

Location: Agricultural Systems Research

Title: A global meta-analysis on the impact of management practices on net global warming potential and greenhouse gas intensity from cropland soils

Author
item Sainju, Upendra

Submitted to: PLoS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/16/2016
Publication Date: 2/22/2016
Publication URL: http://handle.nal.usda.gov/10113/61966
Citation: Sainju, U.M. 2016. A global meta-analysis on the impact of management practices on net global warming potential and greenhouse gas intensity from cropland soils. PLoS One. 11(2): e0148527. doi:10.1371/journal.pone.0148527.

Interpretive Summary: Agricultural management practices contribute from 6% of the total greenhouse gas (GHGs: carbon dioxide, nitrous oxide, and methane) emissions in the USA to about 20% globally. The impact of these GHGs in radiative forcing in earth’s atmosphere is quantitatively estimated by calculating net global warming potential (GWP) which accounts for all sources and sinks of carbon dioxide equivalents from farm operations, chemical inputs, soil C sequestration, and N2O and CH4 emissions. Another measure of GHGs’ impact is net greenhouse gas intensity (GHGI) which is expressed as GWP per unit crop yield. Little is known about the influence of management practices on GWP and GHGI. Several methods have been used to calculate GWP and GHGI based on nitrous and methane emissions and soil organic C sequestration rate ('SOC), but values that account for carbon dioxide equivalents from farm operations, N fertilization, soil respiration, and crop residue returned to the soil in addition to these parameters are lacking. Based on nitrous oxide and methane emissions, GWP varied from 1068 to 7126 kg carbon dioxide equivalent/ha/yr for N fertilization treatments in California and Arkansas. Based on nitrous oxide and methane emissions and 'SOC, GWP varied from 403 to 2900 kg carbon dioxide equivalent/ha/yr for various treatments at different places. Using nitrous oxide and methane emissions, 'SOC, and carbon dioxide equivalents of farm operations and N fertilization, GWP varied from -1291 to 10250 kg carbon dioxide equivalent/ha/yr. Substituting 'SOC by soil respiration and crop residue returned to the soil, GWP varied from -9169 to 9850 kg carbon dioxide equivalent/ha/yr. Similarly, GHGI varied from -2920 to 1860 kg carbon dioxide equivalent/Mg grain/yr for various management practices. The GWP and GHGI were overestimated when 'SOC was not accounted, but underestimated when CO2 sources from farm operations and chemical inputs were not included. Although GWP and GHGI varied due to variations in GHG emissions, soil C sequestration, management practices, crop yields, and soil and climatic conditions, no-till diversified crop rotations with optimum fertilization rate showed the potentials to reduce GWP and GHGI compared to traditional systems.

Technical Abstract: Agricultural practices contribute significant amount of greenhouse gas (GHG) emissions, but little is known about their effects on net global warming potential (GWP) and greenhouse gas intensity (GHGI) that account for all sources and sinks of carbon dioxide emissions per unit area or crop yield. Several methods have been used to calculate GWP and GHGI based on nitrous and methane emissions and soil organic C sequestration rate ('SOC), but values that account for carbon dioxide equivalents from farm operations, N fertilization, soil respiration, and crop residue returned to the soil in addition to these parameters are lacking. Based on nitrous oxide and methane emissions, GWP varied from 1068 to 7126 kg carbon dioxide equivalent/ha/yr for N fertilization treatments in California and Arkansas. Based on nitrous oxide and methane emissions and 'SOC, GWP varied from 403 to 2900 kg carbon dioxide equivalent/ha/yr for various treatments at different places. Using nitrous oxide and methane emissions, 'SOC, and carbon dioxide equivalents of farm operations and N fertilization, GWP varied from -1291 to 10250 kg carbon dioxide equivalent/ha/yr. Substituting 'SOC by soil respiration and crop residue returned to the soil, GWP varied from -9169 to 9850 kg carbon dioxide equivalent/ha/yr. Similarly, GHGI varied from -2920 to 1860 kg carbon dioxide equivalent/Mg grain/yr for various management practices. The GWP and GHGI were overestimated when 'SOC was not accounted, but underestimated when CO2 sources from farm operations and chemical inputs were not included. Although GWP and GHGI varied due to variations in GHG emissions, soil C sequestration, management practices, crop yields, and soil and climatic conditions, no-till diversified crop rotations with optimum fertilization rate showed the potentials to reduce GWP and GHGI compared to traditional systems.