Carbon Footprint of Kernza Perennial Grain in Organic and Nonorganic Production Systems

Perennial grains can serve as substitutes for annual grains, reducing soil degradation, increasing soil organic carbon (SOC), and lowering greenhouse gas (GHG) emissions. One such crop is Kernza Intermediate Wheatgrass (IWG), but its emissions impact remains understudied. This study evaluates the carbon footprint of Kernza under organic and nonorganic management, using a life cycle assessment (LCA) methodology. Net GHG emissions were −1.54 kg CO2e kg–1 grain for organic systems and −1.80 kg CO2e kg–1 grain for nonorganic systems, suggesting nonorganic Kernza production has greater potential for reducing GHG emissions. Yield significantly influences global warming potential (GWP) and land use impacts. Higher yields in nonorganic systems offset GHG emissions per hectare, reducing emissions per kilogram of grain compared to the organic Kernza average. Diesel fuel use and soil emissions were responsible for an average of 80% of emissions, highlighting the role of operational and input-specific factors. These findings emphasize the interplay among yield, emissions intensity, and land use in achieving sustainability goals. The dual-use nature of Kernza as both a grain and forage crop could significantly impact LCA outcomes by allocating GHG emission impacts to each product. As a perennial grain, Kernza holds promise for advancing sustainable food systems.