Soil CO2 efflux dynamics in an integrated crop-livestock system

Authors: AUKEMA, KACEY - University Of Florida; WALLAU, MARCELO - University Of Florida; FAUST, DEREK - Clover Park Technical College; Archer, David; Hendrickson, John; Kronberg, Scott; Liebig, Mark

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2023
Publication Date: 4/16/2023
Citation: Aukema, K.D., Wallau, M.O., Faust, D.R., Archer, D.W., Hendrickson, J.R., Kronberg, S.L., Liebig, M.A. 2023. Soil CO2 efflux dynamics in an integrated crop-livestock system. Soil Science Society of America Journal. 87:948-962. https://doi.org/10.1002/saj2.20546.
DOI: https://doi.org/10.1002/saj2.20546

Interpretive Summary: Soil carbon sequestration by integrated crop-livestock (ICL) systems can concurrently improve soil health and mitigate agriculture’s contribution to climate change. However, detecting carbon changes in soil due to ICL management requires many years of implementation and monitoring in semiarid regions. To understand carbon changes of ICL production over a short timeframe, a 3-yr study was conducted near Mandan, ND, USA. Measurements of crop biomass, carbon dioxide emissions, and soil properties were made in grazed and ungrazed crop rotations and grass pasture. Aboveground crop residue biomass carbon was similar in the ICL and conventional cropping systems, and greater than biomass carbon in grazed pasture. Annual soil carbon dioxide emissions were greater in the ICL, grazed, and ungrazed systems than the conventional cropping system. Cover crops in the ICL system were found to contribute to greater soil CO2 emissions in the spring and fall. Soil organic matter and C mineralization near the soil surface were greater in the ICL system compared to the conventional cropping system. Interseeded cover crops in ICL systems can contribute increased root respiration and enhanced soil organic matter pools relative to conventional cropping systems under semiarid conditions.

Technical Abstract: Integrated crop-livestock (ICL) systems have shown potential to provide a variety of environmental benefits including soil carbon (C) increases relative to conventional row cropping systems. However, studies documenting C dynamics of ICL systems in the northern Great Plains are lacking relative to other agroecosystems. Soil CO2 efflux, crop biomass, and soil organic matter (SOM) pools were monitored over three years in an ICL rotation [corn (Zea mays L.)/soybean (Glycine max L.) – spring wheat (Triticum aestivum L.) + cover crop – cover crop] with fall grazing, a conventional cropping system rotation (corn-spring wheat-soybean) and fall grazed and ungrazed mixed-grass pasture near Mandan, ND USA. Cropped treatments were under no-till management. Annual aboveground crop residue biomass carbon was similar in the ICL and conventional systems, while less in the grazed pasture (4.18, 3.83, and 1.21 Mg C/ha/yr respectively; P =0.039). Annual soil CO2 efflux was greater in the ICL, grazed, and ungrazed pasture systems than the conventional system (8.05, 8.73, 8.25 and 5.81 Mg C/ha/yr, respectively; P <0.001). Among crop phases in the ICL and conventional cropping systems, cover crops contributed to greater CO2 efflux in the spring and fall. Soil organic matter and C mineralization were greater at 0-5 cm in the ICL system compared to the conventional cropping system (6.6 vs. 6.3%, P =0.028 and 248 vs. 184 mg CO2-C/kg, P <0.001, respectively). Interseeded cover crops in ICL systems can contribute increased root respiration and enhanced SOM pools relative to conventional cropping systems under semiarid conditions.