The implementation of the nutrient management planning requirements of the new USEPA CAFO regulations appropriately focuses the livestock industry's attention on nutrient-related issues. However, based on a review of the application of these regulations to a single typical beef feedlot, the following conclusions can be drawn:
- An on-farm nutrient management plan targeting cropping systems as required by the CAFO regulations will reduce the concentration of P on beef cattle feedlots, but the reductions are likely to be small especially for farms with limited land base and significant concentrations of animals.
- The edge of field setback requirements of the CAFO regulations will likely remove some land from manure application resulting in additional purchases of commercial P fertilizer by livestock operations and a small increase in the whole-farm nutrient imbalance. The alternative is to take some land out of production for buffers and purchase additional feed from off-farm sources, further adding to nutrient imbalances.
- Voluntary BMPs may have the greatest environmental benefit for reducing environmental risk on beef cattle feedlots. The export of manure to off-farm users is a valuable BMP alternative for many operations. For some animal feeding operations, dietary options such as removal of by-product feeds high in P will reduce the accumulation of P within feedlots. However, the incentives for introducing these practices are limited at this time.
- Whole-farm nutrient balance provides a valuable tool for measuring nutrient performance and evaluating alternative BMPs. Regulatory and incentive-based programs should consider this as a tool for evaluating the environmental benefit of alternative nutrient strategies.