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ARS Home » Plains Area » Sidney, Montana » Northern Plains Agricultural Research Laboratory » Agricultural Systems Research » Research » Publications at this Location » Publication #395687
Research Project: Ecologically-Sound Pest, Water and Soil Management Practices for Northern Great Plains Cropping Systems

Location: Agricultural Systems Research

Title: Greenhouse gas emissions under perennial bioenergy crops with various nitrogen fertilization rates

Author
item Sainju, Upendra
item Allen, Brett
item Rana Dangi, Sadikshya

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2025
Publication Date: 4/20/2025
Citation: Sainju, U.M., Allen, B.L., Rana Dangi, S. 2025. Greenhouse gas emissions under perennial bioenergy crops with various nitrogen fertilization rates. Journal of Environmental Quality. 25:1-11. https://doi.org/10.1002/jeq2.70021.
DOI: https://doi.org/10.1002/jeq2.70021

Interpretive Summary: Perennial bioenergy crops can provide a significant portion of biofuels for energy, require less inputs and can be grown on marginal lands, but information is lacking on net greenhouse gas (GHG) emissions on perennial bioenergy crops. Researchers at ARS, Sidney, MT determined net GHG emissions by accounting for sources and sinks of GHG under cool- and warm-season grasses and compared them with an annual crop (spring wheat). They reported that switchgrass emitted less GHG compared to intermediate wheatgrass and smooth bromegrass while maintaining aboveground biomass yield when carbon sequestration rate was measured to a depth of 120 cm (4 ft). Increased nitrogen fertilization rate increased GHG emisions. All perennial grasses emitted less net GHG than spring wheat. Producers can reduce net GHG emissions while enhancing biomass yield by planting switchgrass treated with a recommended optimum nitrogen fertilization rate in the northern Great Plains.

Technical Abstract: Little information exists about greenhouse gas (GHG) emissions under perennial bioenergy crops (PBCs) with various N fertilization rates. Our objectives were to evaluate the effect of PBCs receiving various N fertilization rates on N2O and CH4 emissions, GHG balance (GHGB), and yield-scaled GHGB (YSGB) and compare them with an annualcrop from 2012–2013 to 2013 to 2014 in the northern Great Plains. The PBCs were intermediate wheatgrass (IW, Thinopyrum intermedium [Host] Barkworth and Dewey), smooth bromegrass (SB, Bromus inermis L.), and switchgrass (SG, Panicum virgatum L.), and N fertilization rates were 0, 28, 56, and 84 kg N ha-1. The annual crop was spring wheat (WH, Triticum aestivum L.) with 80kg N ha-1. The N2O flux peaked immediately after planting, fertilization, intense precipitation (>15 mm), and snowmelt. Cumulative N2O flux was greater for SG than IW and SB with 56 kg N ha-1 in 2012–2013 and with 28–84 kg N ha-1 in 2013–2014. The CH4 flux was not affected by treatments. Carbon sequestration rate at 0–30 cm from 2009 to 2019 was greater for IW than other PBCs. The GHGB and YSGB were greater for SG and SB than IW with almost all N fertilization rates in both years. Comparing PBCs and an annual crop, cumulative N2O flux, GHGB, and YSGB were greater for SG than IW, SB, or WH in 2013–2014. The IW can reduce GHG emissions per unit area and per unit crop yield compared to other PBCs and WH.