Balancing the phosphorus budget of a swine farm: a case study.

摘要

Trends in animal production have moved the industry toward large confined animal feeding operations (CAFOs). These CAFOs concentrate large amounts of manure-based nutrients in relatively small areas, which increases the risk of nutrient loss to the surrounding environment. In response to water quality concerns, P-based manure application regulations are becoming more common. Mr. Pritchard is the owner and operator of two 4500-head swine (Sus scrofa) farms located in an area of intensive animal production in North Carolina, USA. He has noticed an increasing trend in the soil P concentrations in his manure application fields and realizes that he does not have enough land to apply his anaerobically treated liquid swine manure based on crop P uptake. Mr. Pritchard is now faced with the dilemma of what to do to slow down the P accumulation in his soil. This case constructs a P budget for Mr. Pritchard's farm to examine ways of balancing on-farm nutrients. Students are encouraged to explore solutions related to animal nutrition, crop production, water quality, soil chemistry, and manure management. Furthermore, students should evaluate the appropriate role of government and industry in assisting Mr. Pritchard to protect the environment while remaining a profitable swine producer..