Beef cattle have been identified as the largest contributor to greenhouse gas (GHG) emissions from the livestock sector. Through life cycle analysis (LCA), studies have concluded that grass-fed beef production systems have a higher GHG intensity than feedlot-finished (FL) beef. However, these studies have only used one grazing management system, continuous grazing, to model the environmental impacts of grass-fed production. Adaptive multi-paddock (AMP) grazing is a management system with improved animal and forage productivity, as well as potential soil carbon (SOC) sequestration, compared with continuous grazing through high animal stocking on short grazing intervals with pasture recovery periods. To examine the impacts of AMP grazing and SOC sequestration on net GHG emissions, a comparative LCA was executed for two finishing systems in the Upper Midwest: AMP grazing and FL using, on-farm data from the Lake City AgBioResearch Center. Impact scope included GHG emissions from enteric CH4, feed and mineral supplement production, manure, and on-farm energy use and transportation, as well the potential C sink arising from SOC sequestration. Across-farm SOC data showed a four-year C sequestration rate of 3.59 Mg C ha=1 yr-1. After including SOC into the GHG footprint, emissions from the AMP system were reduced from 9.62 to -7.92 kg CO2-e kg CW-1, while FL emissions remained at 7.02 kg CO2-e kg CW-1. This indicates that AMP grazing might offset emissions through soil C sequestration and therefore that the finishing stage may be a net C sink. More long-term research is needed to confirm soil C sequestration in other ecoregions and its potential impact on GHG mitigation in beef production system.
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