Systems-Level Analysis of Phosphorus Flows in the Dairy Supply Chain

摘要

The dairy sector plays a vital role in the food supply chain, but it is also highly resource-intensive, consuming vast amounts of water, energy, and nutrients. Nutrients such as phosphorus (P) are key economic drivers in this interconnected system, as they serve as catalysts that enable efficient production of crops that in turn support dairy cow diet requirements and subsequent production of milk and derived products such as cheese and ice cream. As such, the dairy sector is tightly interconnected with mining, chemical, agricultural, and urban sectors. Unfortunately, nutrients are also emitted throughout the supply chain and create widespread environmental impacts. Specifically, P losses that result from urban discharges and overapplication of fertilizer in croplands impact the quality of water reservoirs (e.g., eutrophication). Moreover, natural P resources are finite, and thus efficient recycling and reuse of this valuable nutrient are essential to ensure the long-term viability of the dairy sector. In this work, we provide a systems-level analysis framework that captures the flow of inorganic P throughout the dairy sector and its interdependent sectors. We use this framework to analyze how changes in different sectors and externalities propagate throughout the system. A case study using real data for the State of Wisconsin is used to illustrate the insights that can be obtained with the proposed framework.