Location: Agricultural Systems ResearchTitle: Soil carbon dioxide and methane emissions and carbon balance with crop rotation and nitrogen fertilization
Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2021
Publication Date: 6/25/2021
Citation: Sainju, U.M., Ghimire, R., Rana Dangi, S. 2021. Soil carbon dioxide and methane emissions and carbon balance with crop rotation and nitrogen fertilization. Science of the Total Environment. 775. Article 145902. https://doi.org/10.1016/j.scitotenv.2021.145902.
Interpretive Summary: Information on the carbon footprint of cropping systems is needed to know if the systems are carbon sources or sinks that contribute to global warming. ARS researchers at Sidney, MT in collaboration with New Mexico State University examined the four-year effect of crop rotation and nitrogen fertilization rates on carbon dioxide and methane emissions and carbon balance in the northern Great Plains. They reported greater carbon dioxide but lower methane emissions in continuous spring wheat than in a wheat-pea rotation at higher nitrogen fertilization rates. Yield-based carbon dioxide emissions and carbon balance were not affected by treatments, but all systems were shown to be carbon sources. Producers can reduce carbon dioxide and methane emissions by using legume-nonlegume crop rotations with reduced nitrogen fertilization rates.
Technical Abstract: Information is needed about the effect of crop rotation and N fertilization rate on CO2 and CH4 emissions and C balance under dryland cropping systems in arid and semiarid regions. The objective of this study was to examine the effect of crop rotation and N fertilization rate on CO2 and CH4 fluxes and C balance under dryland farming from 2012-2013 to 2015-2016 in the northern Great Plains, USA. Treatments were two crop rotations (continuous spring wheat [Triticum aestivum L.], CW; and spring wheat-pea [Pisum sativum L.], WP) and four N fertilization rates (0, 50, 100, and 150 kg N ha-1) applied to spring wheat. The CO2 flux peaked immediately after planting, fertilization, and intense precipitation (>15 mm) when the emissions varied among treatments. Treatments had minor effect on CH4 uptake, except the uptake varied with N fertilization rate in 2015-2016. Cumulative annual CO2 flux was greater with CW than WP at 50-150 kg N ha-1 in 2013-2014 and 2015-2016, but was greater with WP than CW at 100 kg N ha-1 in 2014-2015. Mean cumulative CH4 flux was greater with CW than WP at 0 kg N ha-1, but was greater with WP than CW at 150 kg N ha-1. Yield-based CO2 and CH4 fluxes were unaffected by treatments, but varied among years. Carbon balance was negative and unaffected by treatments. Legume-nonlegume crop rotation and reduced N fertilization rate decreased CO2 emissions with limited impact on CH4 emissions. Dryland spring wheat-based cropping systems was a carbon source in the semiarid region.