The New York City Watershed Agricultural Program (NYCU7AJP) seeks to reduce the potential for phosphorus movement from farms to surface waters. Toward this objective, a Phosphorus Index for Site Evaluation P-Index) provides planners in the NYCWAP with a tool for identifying problems and evaluating solutions. A linear programming model was used to examine dairy farm resource use and profitability given resource constraints and constraints on the values of the P-Index. Results indicate dramatic differences in expected effects on resource use and returns above variable costs between less restrictive targets in the upper end of the medium (for example, 24 and 17) and more restrictive targets in the lower end of the range (for example, 13 through 10). The differences have implications for choosing a target to guide planning on farms - regarding expected effects on profitability, the target within the medium range matters.