Phosphorus-based nutrient plan required under new rules

Under proposed EPA water quality rules greater emphasis will be placed on applying manure for conservation purposes and to reduce reduce nutrient loss from runoff. Proposed EPA rules may mandate that manure application rates must be based on a phosphorus-based nutrient plan instead of the current nitrogen plan.

The proposed rules make significant changes in the planning and record keeping a farmer must do on land receiving manure. The single largest change is that farmers must base manure application rates on the phosphorus content of their manure if soil test phosphorus is above a certain level. If soil-test phosphorus is too high, no manure may be applied to a field.

Up to now, farmers could apply manure based on the nitrogen need of the crop. In some cases, such as poultry litter and hog or cow slurry, a nitrogen-based strategy can result in a rapid build up of soil-test phosphorus on fields that receive annual applications of manure.

The proposed rules implement a system to evaluate phosphorus levels in the soil and determine if a farmer can continue applying manure based on the current nitrogen system, or must apply manure based on phosphorus, or not apply manure. For planning purposes most farmers, under these rules, should assume they will need to use a phosphorus limit.

Applying manure based on phosphorus levels can require double the land or more compared to the current nitrogen system. Exact land requirements depend on the crops grown and the nutrient concentration in the manure.

Operations using injected unagitated lagoon effluent will require the least change in land needed; operations using poultry litter will require the greatest changes. Other significant new requirements for the nutrient plan proposed by EPA include the following.

• Plans must be written or renewed by a certified nutrient management specialist.
• Plans must be renewed every five years and reviewed annually.
• Plans must include crop sequence and yield goals for five years for every field.
• Soil tests must be taken on all fields for phosphorus every three years with no more than 20 acres per soil sample.
• Manure must be tested for nutrient content each year.
• The plan must calculate manure application rates and stipulate the best time of the year for applying manure.
• A nitrogen, phosphorus, and potassium nutrient balance must be calculated for each field.

Under the proposed rules, all permitted operations must have a written permit nutrient plan. The plan or a plan summary must be available for public review. Farmers who fail to follow their plans can be fined for violating the Clean Water Act under the point source rules.

Furthermore, EPA proposes that if water quality goals are not being met by the current permit nutrient plan additional restrictions can be added at a later date.

All farmers who apply manure are expected to follow a permit nutrient plan. The EPA is considering a requirement that each permitted livestock producer who sells or gives away manure to document that manure applied off the farm is covered by a permit nutrient plan.