Response of soil surface greenhouse gas fluxes to crop residue removal and cover crops under a corn-soybean rotation

Authors: WEGNER, BRIANNA - South Dakota State University; SUBEDI, KOPILA - South Dakota State University; SINGH, SHIKHA - South Dakota State University; LAI, LIMING - South Dakota State University; ABAGANDURA, GANDURA OMAR - South Dakota State University; KUMAR, SANDEEP - South Dakota State University; Osborne, Shannon; Lehman, R - Michael; JAGADAMMA, SINDHU - South Dakota State University

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/16/2018
Publication Date: 9/6/2018
Citation: Wegner, B.R., Subedi, K., Singh, S., Lai, L., Abagandura, G., Kumar, S., Osborne, S.L., Lehman, R.M., Jagadamma, S. 2018. Response of soil surface greenhouse gas fluxes to crop residue removal and cover crops under a corn-soybean rotation. Journal of Environmental Quality. 47:1146-1154.

Interpretive Summary: Large amounts of corn residue returned to the soil can have a negative impact on farming operations, but removing it can affect soil and environmental quality. Incorporating cover crops can add additional residue to the soil and improve soil and environmental quality compared with no cover cropping. Residue and cover crops impacts on greenhouses gases (GHG) emissions are undetermined and site specific. Our research project was conducted to investigate the impacts of corn residue management and cover cropping on greenhouse gas fluxes. The research was conducted in Brookings, South Dakota in static chambers under a corn and soybean rotation, during the years 2013-2015 from a long-term experiment initiated in 2000. Treatments included two residue management levels (residue returned, RR; and residue not returned, RNR) and two cover cropping (cover crops and no cover crops). Results showed that RR under two phases significantly reduced cumulative CO2 fluxes compared to RNR in 2013. The RR emitted significantly less cumulative N2O than RNR from both phases in 2013 and 2014, but not in 2015. The cover crop treatment reduced cumulative N2O fluxes compared to the no cover crop from corn and soybean phases in 2013 and 2014. Our research concluded that leaving crop residue on the soil and including cover cropping can mitigate the greenhouse gas emissions compared to residue removal and no cover cropping.

Technical Abstract: Excessive crop residue returned to the soil hinders farm operations, but residue removal can affect soil and environmental quality. In contrast, cover cropping can return additional residue to the soil and improves soil and environmental quality compared with no cover cropping. Residue and cover crops impacts on greenhouses gases (GHG) emissions are undetermined and site specific. Thus, the present study was conducted to investigate the impacts of corn residue management and cover cropping on GHG fluxes. The fluxes were measured from 2013 to 2015 using static chamber under corn (Zea mays L.) and soybean (Glycine max L.) rotation initiated in 2000 at Brookings, South Dakota. Treatments included two residue management levels (residue returned, RR; and residue not returned, RNR) and two cover cropping (cover crops, CC; and no cover crops, NCC). Results showed that RR under two phase’s significantly reduced cumulative CO2 fluxes (2681.32 kg ha-1 in corn and 2419.79 kg ha-1 in soybeans) compared to RNR (3331.00 kg ha-1 in corn and 2755.04 kg ha-1 in soybeans) in 2013. The RR emitted significantly less cumulative N2O fluxes than RNR from both phases in 2013 and 2014, but not in 2015. The CC treatment had significantly lower cumulative N2O fluxes than NCC from corn and soybean phases in 2013 and 2014. We conclude that crop residue retention and cover cropping can mitigate the GHG emissions compared to residue removal and no cover cropping.