Constraining Phosphorus in Surface Waters of the New York City Watershed: Dairy Farm Resource Use and Profitability

The New York City Watershed Agricultural Program seeks to reduce the potential for phosphorus movement from farms to surface waters. A “phosphorus index for site evaluation” (P-index) provides planners in the New York City Watershed Agricultural Program with a tool for identifying individual farm business, phosphorus related problems, and evaluating solutions. A linear programming model is employed to examine dairy farm resource use and profitability, with the P-index used to impose phosphorus movement constraints. Results indicate dramatic differences in farm resource use and farm business profitability depending on the level of the P-index. Small changes in the target index level result in large shifts in optimal resource use and business profitability. These differences illustrate that restrictions on phosphorus movement from land to surface waters potentially have major impacts on resource use and farm profitability in the New York City Watershed.