title: Exploring a water/energy trade-off in regional sourcing of livestock feed crops.
abstract: Feed production constitutes a major portion of the energy and water resource inputs in modern livestock production. Schemes to reduce these inputs may include local sourcing of animal feed. However, in water stressed regions where irrigation of feed crops is necessary, a trade-off between local sourcing (with high water stress) and transport from less water stressed regions can occur. We demonstrate this trade-off in the U.S. by combining state-level irrigation water use and pumping energy demand from USDA surveys with fertilizer and transportation energy demands for producing major feed crops (corn grain, soybean, alfalfa hay, corn silage) in each state and delivering them to two hypothetical dairy farms located in Kersey, CO and Rosendale, WI. A back-up technology approach is employed to express freshwater resource depletion in units of energy, allowing direct comparison with other energy resource demands. Corn grain, soybean, and alfalfa hay delivered to CO demonstrate a clear trade-off between transportation energy (proportional to the distance between CO and the production state) and water stress. On the other hand, transportation burdens dominate for corn silage, making local production most attractive, even in water stressed regions. All crops delivered to WI (a region of low water stress and minimal irrigation) are dominated by transportation burdens, making local production preferable, but this is clearly not a universal principal, as other cases show. This paper quantitatively elucidates the water-energy trade-off in sourcing feed for livestock and the method is expected to be applicable in managing supply chain logistics of other farm commodities.
authors: Center for Sustainable Systems, School of Natural Resources and Environment, University of Michigan, 3012 Dana Building, 440 Church Street, Ann Arbor, Michigan 48109-1041, United States. mcheller@umich.edu
authors: Martin C
authors: MC
authors: Heller
authors: Gregory A
authors: GA
authors: Keoleian
mesh_terms: D000383:Agriculture / Q000379:methods / Q000706:statistics & numerical data*; D000821:Animal Feed / Q000706:statistics & numerical data*; D003247:Conservation of Natural Resources / Q000379:methods*; D018556:Crops, Agricultural / Q000254:growth & development*; D014481:United States; D016885:United States Department of Agriculture; D058438:Water Cycle; D014881:Water Supply / Q000032:analysis / Q000706:statistics & numerical data*