Greenhouse Gas Fluxes from Integrated Crop-Livestock Systems in Central North Dakota.

Integrated crop-livestock (ICL) systems have shown potential to achieve environmentally sustainable production of crop and livestock products with regards to improved soil health. Reduction of greenhouse gas (GHG) emissions relative to crop and/or livestock only production systems would increase sustainability in ICL systems. Greenhouse gas soil flux data were collected using static chambers starting in October 2016 in a central North Dakota ICL plot-scale study with a corn/soybean intercrop (Zea mays L., Glycine max (L.) Merr.)-spring wheat (Triticum aestivum L.)-perennial and annual cover crop mixture under no-till management. Objectives of this study were to compare: 1) GHG fluxes of grazing in ICL systems and grass pastures, and 2) GHG fluxes of grazed and ungrazed plots. Grazing in cropped plots increased cumulative CO₂ flux compared to ungrazed crops (p = 0.028). Uptake of atmospheric CH₄ was prevalent across treatments, with cumulative CH₄ uptake significantly greater in ungrazed crops compared to grazed grass (P = 0.040). Cumulative N₂O flux was greater in grazed crops compared to grazed (P = 0.047) and ungrazed grass (P = 0.035). Preliminary evaluation of ICL treatments suggest grazing of cover crops increased soil CO₂ emissions but not CH₄ or N₂O efflux compared to ungrazed crops. Continued determination of GHG fluxes in ICL systems will allow for evaluation of impacts throughout the rest of the crop rotation.