Using Whole Farm Nutrient Balance as a Tool for Evaluating Nutrient Management Plans.

Whole farm nutrient balances assess the amount of nutrients entering the farm boundary (feed, fertilizer, animals, etc.) relative to the amount of nutrients leaving the farm in the form of products (milk, animals, crops, manure, etc.). In 2005, a statewide project was initiated in New York State to assess N, P, and K balances of dairy farms. Currently about 100 dairy farms are participating in the project. Results to date have shown the mass balance assessment to be an effective tool in identifying N, P, and K use per unit milk produced and nutrient remaining per unit cropland. Integration of data collected for nutrient management planning and for mass balances allows for assessment of agricultural environmental indicators that aid in the identification of management options that can lower annual nutrient loss (N) and/or accumulation (P and K).