Soil Greenhouse Gas Responses to Biomass Removal in the Annual and Perennial Cropping Phases of an Integrated Crop Livestock System

Diversifying agronomic production systems by combining crops and livestock (i.e., Integrated Crop Livestock systems; ICL) may help mitigate the environmental impacts of intensive single-commodity production. In addition, harvesting row-crop residues and/or perennial biomass could increase multi-functionality ICL as a potential source for second-generation bioenergy feedstock. Here, we evaluated non-CO2 soil greenhouse gas (GHG) emissions from both grass phases field-scale model system established on marginally productive, poorly drained cropland in western US Corn Belt. Soil nitrous oxide (N2O) methane (CH4) were measured during 2017–2019 growing seasons under continuous corn (Zea mays L.) treatments consisting common pasture species, ‘Newell’ smooth bromegrass (Bromus inermis L.), two cultivars switchgrass (Panicum virgatum ‘Liberty’ ‘Shawnee.’ system, impact stover removal mechanical baling vs. grazing with without winter cover crop, triticale (x Triticosecale neoblaringhemii A. Camus; hexaploid AABBRR). grasslands, effect no grazing. We found that (1) N2O are generally higher than grasslands due to synthetic N fertilizer use; (2) crop use had total GHG regardless management treatment; (3) decreased emissions, though significantly increased one year; (4) tended pastures selected forage quality, but highly variable year (5) incorporate grasses will provide most effective mitigation outcomes.