Cover Crop Effects on Greenhouse Gas Emissions and Global Warming Potential in Furrow-Irrigated Corn in the Lower Mississippi River Valley

Corn (Zea mays) production systems are described as high risk for emissions of greenhouse gases (GHG) due to large fertilizer inputs. Conservation practices, such as cover crop (CC), can limit the effects of agricultural activities on GHGs while increasing carbon and nitrogen storage. The objective of the study was to assess the effects of cover crops, i.e., with CC and no-CC, on GHG (i.e., CO2, CH4, and N2O) emissions and global warming potential (GWP) in furrow-irrigated corn in the Lower Mississippi River Valley. Gas sampling was conducted with an automated system that measured GHGs four times daily during the 2024 growing season in furrow-irrigated corn on a loam soil in Mississippi. Only CO2 emissions differed (p < 0.05) by CC treatment, with soil respiration ~30% greater from CC than no-CC. Season-long emissions ranged from −0.22 to 0.30 kg CH4 ha−1 season−1, 5.53 to 7.28 kg N2O ha−1 season−1, with a GWP between 12,888 and 15,053 kg CO2 eq. ha−1 season−1 from no-CC and CC, respectively. The role of CC as a conservation practice needs to be evaluated with soil and plant parameters. The beneficial effects of CC on soil physical and chemical properties likely outweigh a predictable increase in GHG emissions.