Effects of cover crops and soil amendments on soil CO2 fluxes in Mississippi corn cropping system on upland soil

Authors: HU, JING - Mississippi State University; Miles, Dana; Adeli, Ardeshir; Brooks, John; Podrebarac, Frances; Smith, Renotta; LEI, FANGNI - University Of Connecticut; LI, XIAOFEI - Mississippi State University; Jenkins, Johnie; MOOREHEAD II, ROBERT - Mississippi State University

Submitted to: Environments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2023
Publication Date: 1/26/2023
Citation: Hu, J., Miles, D.M., Adeli, A., Brooks, J.P., Podrebarac, F.A., Smith, R.K., Lei, F., Li, X., Jenkins, J.N., Moorehead Ii, R.J. 2023. Effects of cover crops and soil amendments on soil CO2 fluxes in Mississippi corn cropping system on upland soil. Environments. 10(2):19. https://doi.org/10.3390/environments10020019.
DOI: https://doi.org/10.3390/environments10020019

Interpretive Summary: Agriculture, accounting for more than one-third of arable land worldwide, plays an important role in the terrestrial carbon cycle. Development of agricultural practices maximizing soil carbon storage from the atmosphere is receiving growing attention due to the recognition of agroecosystems' great potential to serve as sinks of atmospheric carbon dioxide (CO2) and mitigate climate change. Cover crop and soil amendment applications are generating much interest in mitigating climate change and enhancing ecosystem services from agricultural systems. The objective of this study was to evaluate the effects of winter cover crop and soil amendment, including broiler litter (BL), flue gas desulfurization (FGD) gypsum and lignite, on soil CO2 fluxes from cropping systems in the southeastern USA. A field study was conducted from 2019 to 2021 in the Mississippi upland corn cropping system with measurements of soil CO2 flux, moisture and temperature during cash crop growing seasons. We observed high temporal variability in soil CO2 flux with flux peaks between late June and early July, which is likely due to temporal changes in soil moisture. A significant increase in soil CO2 flux was found with BL application. Co-application FGD gypsum and lignite with BL reduced soil CO2 fluxes by 15-23% but did not fully eliminate the rising effects from BL. Significantly higher soil CO2 fluxes and lower soil temperature were observed from fields with cover crop than without cover crop in the third year of this study, which is likely attributed to the higher organic carbon content accumulated in soil with cover crop. Future research should assess year-around soil greenhouse gas fluxes in both cash crop and cover crop growing seasons using a high temporal resolution measurement scheme.

Technical Abstract: Agroecosystems, accounting for more than one-third of arable land worldwide, play an important role in the terrestrial carbon (C) cycle. Development of agricultural practices maximizing soil C sequestration from the atmosphere is receiving growing attention due to the recognition of agroecosystems' great potential to serve as sinks of atmospheric carbon dioxide (CO2) and mitigate climate change. Cover crop and soil amendment applications are generating much interest in mitigating climate change and enhancing ecosystem services from agricultural systems. The objective of this study was to evaluate the effects of winter cover crop and soil amendment, including broiler litter (BL), flue gas desulfurization (FGD) gypsum and lignite, on soil CO2 fluxes from cropping systems in the southeastern USA. To achieve the goal, a field study was conducted from 2019 to 2021 in the Mississippi upland corn cropping system with measurements of soil CO2 flux, moisture and temperature during cash crop growing seasons. We observed high temporal variability in soil CO2 flux with flux peaks between late June and early July, which is likely due to temporal changes in soil moisture. A significant increase in soil CO2 flux was found with BL application (P < 0.05). Co-application FGD gypsum and lignite with BL reduced soil CO2 fluxes by 15-23% but did not fully eliminate the rising effects. Significantly higher soil CO2 fluxes and lower soil temperature were observed from fields with cover crop than without cover crop in the third year of this study (P < 0.05), which is likely attributed to the higher organic C content accumulated in soil with cover crop. Future research should assess year-around soil greenhouse gas fluxes in both cash crop and cover crop growing seasons using a high temporal resolution measurement scheme.