A cradle to farm gate life cycle analysis of water use in U.S. pork production.

摘要

The intent of this study was to analyze water use across a range of regions, scales and practices of the U.S. pork industry. A Life Cycle Assessment of water use within the pork supply chain was performed. Cumulative water use was the environmental impact category used in the LCA to evaluate the impacts of pork production processes throughout the pork supply chain. The functional unit for the analysis was the volume of water required to produce one kilogram of swine (live weight) at the farm gate. A comprehensive literature review was used to design and propagate algorithms for the National Pork Board Pig Production Environmental Footprint Calculator (version 2.0). The outputs from the calculator were used to generate lifecycle inventory inputs for unit processes in SimaPro (Pre' Consultants, The Netherlands), an LCA modeling program. The LCA method was then used to assess the water footprint for swine production from cradle to farm gate production scenarios. There were 240 different scenarios analyzed that were a combination of ten regions, three production strategies and three scales. The grow/finish barn phase of the on farm water footprint requires approximately five times as much water as the sow and nursery barns irrespective of the barn infrastructure. Water used to irrigate swine feed crops contributed 89% of the total cradle to farm gate footprint. Since all 240 scenarios were analyzed with the same ration inputs, the final footprints did not vary drastically between scenarios. There were small deviations such as tunnel ventilated production systems consistently required more water than hoop barns due to cooling systems in warmer regions. Smaller scale operations consistently had higher water footprints due to economy of scale, although the footprint differences between scales were marginal. Regarding the water use that occurred on the swine farm, drinking water was by far the most significant contributor to the footprint (81%). Production strategies, production scale and region of production were all statistically significant (p < 0.0001) and affected the blue water footprint. This may seem self-evident, but these processes have not been quantified at this scale prior to this analysis.