Phosphorus and nitrogen, both macronutrients required for plant life, can pose specific threats to surface and ground waters. Phosphorus, found in fertilizers and animals wastes, can cause harm by accelerating algae growth, lowering dissolved oxygen, and contributing to fish death when supplied in excess concentrations to aquatic ecosystems. Nitrogen, also a component of fertilizers and animal wastes, poses a threat to human health when present in excess concentrations in drinking water.

Through the implementation of a nutrient management plan, associated site-specific management techniques (conservation practices), and precise calculation of crop nutrient requirements, nutrients are precisely targeted to the growing of crops and forages, resulting in increased water resource protection.

A Nutrient Management Plan (NMP) includes:

• A description of the farm and a resource inventory;
• Maps of the production and land application areas;
• Soil and manure/waste testing;
• An estimate of yearly manure/waste production;
• Nutrient recommendations (N, P, and K) per field based on soil testing;
• Planned manure/waste and fertilizer applications;
• A nutrient budget;
• Soil loss estimates using RUSLE2 and conservation practices to limit erosion to the tolerable soil loss;
• The Nitrate Leaching Index and conservation practices to mitigate nitrogen mobility on vulnerable soils;
• The Phosphorus Index and conservation practices to mitigate phosphorus mobility on vulnerable sites; and
• An assessment of manure/waste storage and handling within the production area.

For a detailed explanation of nutrient management requirements for:

• Small Farm Operations (SFO), see the Accepted Agricultural Practices;
• Medium Farm Operations (MFO), see the General Permit for MFOs; and
• Large Farm Operations (LFO), see the LFO Law and Regulations.