(334b) Consumption-Based Accounting for Tracing Nutrient Footprints of Beef Supply Chains in the United States

Food supply chains span multiple spatial and temporal scales and have evolved to become increasingly complex. Food products go through many different processing steps before being ready for consumption. While highly connected food chains provide numerous benefits, they lack traceability. As such, understanding their resiliency, security, and associated environmental burdens of consumption become difficult. One specific class of impacts is the nutrient footprint of food consumption. Application of synthetic fertilizers and release of reactive nitrogen and phosphorus has been linked to degradation in water quality and loss of biodiversity across the globe. Beef production involves consumption of large quantities of animal feed, the production of which is heavily dependent on fertilizer application. Although there is a rich body of work on nutrient footprint estimation for beef production, there is a gap in the literature regarding the spatial distribution of the nutrient releases throughout the supply chain. Additionally, bulk of the studies focus on production related impacts making it difficult to trace environmental impacts of beef consumption that typically occur far from the point of consumption.

We develop an optimization-based framework to model supply chain networks of beef products at the county level. Using publicly available data, we construct a weighted network of nutrient flows based on nutrient mass balance, including synthetic fertilizers, manure production, and crop uptake and residues. Preliminary results show that the beef supply chain is highly concentrated in the central region of the United States, with a majority of slaughtering facilities owned by a small number of companies. Additionally, there is a large inflow of cattle to the central region for feeding and slaughtering. Feed is sourced from several different counties and states depending on the specific crop type. Analysis reveals that most states consume far more meat than they produce within their boundaries, and highly populated areas are reliant on the inflow of products from the Midwest. Our results also highlight the disparity between production and consumption-based impacts and spatial heterogeneity in nutrient footprint of beef. Implications of these findings for reducing the environmental impacts of beef supply chain, consumer food choice, and policymaking will be discussed.