Evaluation of phosphorus-based nutrient management strategies in Pennsylvania

ABSTRACT:

Farm management and financial impacts of three phosphorus (P) nutrient management strategies outlined in the U.S. Department of Agriculture (USDA) and U.S. Environmental Protection Agency (USEPA) (1999) Unified Strategy for Animal Feeding Operations—soil test crop response (STCR), environmental soil P threshold (ESPT), and P Index (PI)—were evaluated on ten Pennsylvania farms. For each farm, a nutrient management plan (NMP) writer and project economist developed one nitrogen-based and three P-based NMPs and associated partial budgets. Greater management and financial restrictions occurred on high animal density (> 2 animal equivalent units ac⁻¹) and multiple production enterprise farms. Although NMPs for the PI were more expensive to develop, writers and farmers found it the most flexible and practical strategy. Variable P-based NMP impacts indicated the need for a strategy such as the PI that accounted for multiple farm management factors. First-year total NMP implementation costs (across all ten farms) were $61,690 for the STCR, $47,862 for the ESPT, and $45,380 for the PI.