Environmental impacts of eco-nutrition swine feeding programs in spatially explicit geographic regions of the United States.

This study was conducted to determine greenhouse gas (GHG) emissions, water consumption, land use, as well as nitrogen (N), phosphorus (P), and carbon (C) balance of five diet formulation strategies and feeding programs for growing-finishing pigs (25-130 kg body weight) in the three spatially explicit geographic regions where the majority of U.S. pork production occurs. Feeding programs evaluated consisted of 1) standard corn-soybean meal (CSBM) diets, 2) CSBM containing 15% corn distillers dried grains with solubles (DDGS), 3) CSBM with 8.6% thermally processed supermarket food waste (FW), 4) low crude protein CSBM diets supplemented with synthetic amino acids (SAA), and 5) CSBM with phytase enzyme (PHY) added at 600 FTU (phytase units)/kg of diet. An attributional Life Cycle Assessment approach using a highly specialized, spatially explicit Food System Supply-Chain Sustainability (FoodS3) model was used to quantify GHG emissions, water consumption, and land use of corn, soybean meal, and DDGS based on county level sourcing. The DDGS, FW, and SAA feeding programs had less estimated N and P intake and excretion than CSBM, and the PHY feeding program provided the greatest reduction in P excretion. The FW feeding program had the least overall GHG emissions (319.9 vs. 324.6 to 354.1 kg CO2 equiv./market hog), land use (331.5 vs. 346.5 to 385.2 m2/market hog), and water consumption (7.64 vs. 7.70 to 8.30 m3/market hog) among the alternatives. The DDGS feeding program had the greatest GHG emissions (354.1 kg CO2 equiv./market hog) among all programs but had less impacts on water consumption (7.70 m3) and land use (346.5 m2) per market hog than CSBM and PHY. The SAA feeding program provided a 6.5-7.4% reduction in land use impacts compared with CSBM and PHY, respectively. Regardless of feeding program, the Midwest had the least contributions to GHG emissions and land use attributed to feed and manure among regions. Water consumption per market hog associated with feeding programs was much greater in the Southwest (59.66-63.58 m3) than in the Midwest (4.45-4.88 m3) and Mid-Atlantic (1.85-2.14 m3) regions. Results show that diet composition and U.S. geographic region significantly affect GHG emissions, water consumption, and land use of pork production systems, and the potential use of thermally processed supermarket food waste at relatively low diet inclusion rates (<10%) can reduce environmental impacts compared with other common feeding strategies.

Very few studies have been conducted to determine the differences in environmental impacts based on the diet composition of growing-finishing swine feeding programs across major pork production regions in the United States. Therefore, the objective of this study was to determine and compare greenhouse gas (GHG) emissions, water consumption, land use, as well as nitrogen (N), phosphorus (P), and carbon (C) balance of five diet formulation strategies and feeding programs for growing-finishing pigs (25­130 kg body weight) in the three spatially explicit U.S. pork production regions. The corn dried distillers grains with solubles (DDGS), food waste (FW), and low protein-synthetic amino acid (SAA) diets had less estimated N and P excretion compared with corn-soybean meal (CSBM) diets, and the addition of phytase (PHY) to CSBM diets resulted in the greatest reduction in P excretion among feeding programs. Adding FW to diets resulted in the least overall greenhouse gas emissions, water consumption, and land use compared with all other feeding programs, and land use was less for the DDGS and SAA feeding programs than CSBM and PHY feeding programs. The Midwest had the least GHG emissions and land use impact compared with other regions, while the Southwest region had the greatest water consumption associated with feeding programs.

Effects of Spatial Scale on Life Cycle Inventory Results.

Efforts to compile life cycle inventory (LCI) data at more geographically refined scales or resolutions are growing. However, it remains poorly understood as to how the choice of spatial scale may affect LCI results. Here, we examine this question using U.S. corn as a case study. We compile corn production data at two spatial scales, state and county, and compare how their LCI results may differ for state and national level analyses. For greenhouse gas (GHG) emissions, estimates at the two scales are similar (<20% of difference) for most state-level analyses and are basically the same (<5%) for national level analysis. For blue water consumption, estimates at the two scales differ more. Our results suggest that state-level analyses may be an adequate spatial scale for national level GHG analysis and for most state-level GHG analyses of U.S. corn, but may fall short for water consumption, because of its large spatial variability. On the other hand, although county-based LCIs may be considered more accurate, they require substantially more effort to compile. Overall, our study suggests that the goal of a study, data requirements, and spatial variability are important factors to consider when deciding the appropriate spatial scale or pursuing more refined scales.

Subnational mobility and consumption-based environmental accounting of US corn in animal protein and ethanol supply chains.

Corn production, and its associated inputs, is a relatively large source of greenhouse gas emissions and uses significant amounts of water and land, thus contributing to climate change, fossil fuel depletion, local air pollutants, and local water scarcity. As large consumers of this corn, corporations in the ethanol and animal protein industries are increasingly assessing and reporting sustainability impacts across their supply chains to identify, prioritize, and communicate sustainability risks and opportunities material to their operations. In doing so, many have discovered that the direct impacts of their owned operations are dwarfed by those upstream in the supply chain, requiring transparency and knowledge about environmental impacts along the supply chains. Life cycle assessments (LCAs) have been used to identify hotspots of environmental impacts at national levels, yet these provide little subnational information necessary for guiding firms' specific supply networks. In this paper, our Food System Supply-Chain Sustainability (FoodS3) model connects spatial, firm-specific demand of corn purchasers with upstream corn production in the United States through a cost minimization transport model. This provides a means to link county-level corn production in the United States to firm-specific demand locations associated with downstream processing facilities. Our model substantially improves current LCA assessment efforts that are confined to broad national or state level impacts. In drilling down to subnational levels of environmental impacts that occur over heterogeneous areas and aggregating these landscape impacts by specific supply networks, targeted opportunities for improvements to the sustainability performance of supply chains are identified.

Optimizing Eco-Efficiency Across the Procurement Portfolio.

Manufacturing organizations' environmental impacts are often attributable to processes in the firm's upstream supply chain. Environmentally preferable procurement (EPP) and the establishment of environmental purchasing criteria can potentially reduce these indirect impacts. Life-cycle assessment (LCA) can help identify the purchasing criteria that are most effective in reducing environmental impacts. However, the high costs of LCA and the problems associated with the comparability of results have limited efforts to integrate procurement performance with quantitative organizational environmental performance targets. Moreover, environmental purchasing criteria, when implemented, are often established on a product-by-product basis without consideration of other products in the procurement portfolio. We develop an approach that utilizes streamlined LCA methods, together with linear programming, to determine optimal portfolios of product impact-reduction opportunities under budget constraints. The approach is illustrated through a simulated breakfast cereal manufacturing firm procuring grain, containerboard boxes, plastic packaging, electricity, and industrial cleaning solutions. Results suggest that extending EPP decisions and resources to the portfolio level, recently made feasible through the methods illustrated herein, can provide substantially greater CO2e and water-depletion reductions per dollar spend than a product-by-product approach, creating opportunities for procurement organizations to participate in firm-wide environmental impact reduction targets.