ARS | Publication request: OPTIONS IN DEVELOPING FORAGE SYSTEMS FOR REMEDIATING SOIL P ON POULTRY FARMS

Submitted to: Use of Organic and Inorganic Amendments Derived from Waste By-Products
Publication Type: Government Publication
Publication Acceptance Date: March 29, 2002
Publication Date: N/A

Interpretive Summary: Manure generated on poultry farms is typically utilized as a fertilizer for pastures. A problem with this practice has been that high concentrations of phosphorous (P) in poultry manure can lead to a buildup of soil P, which poses an environmental risk by escalating P in runoff to levels that can contaminate surface waters. An approach to reducing soil phosphorous is to develop and manage forage systems to increase the uptake and utilization of soil P. These systems should provide maximum annual distribution of herbage growth. One such system is to overseed warm-season, perennial grass pastures with cool-season annual grasses. Extrapolations from existing data indicate that a warm-season perennial grass , such as bermudagrass, can be placed under intensive hay production to remove up to 60 kg P/hectare in a productive year. Cool- season grasses can be cut as haylage or grazed by growing calves from fall to early spring and then cut for hay in the late growing season. Extrapolations show that combining grazing and hay production on a cool- season grass, such as ryegrass, can remove 15 to 20 kg P/hectare in a productive year. Use of intensively utilized forage systems is an option in reducing soil P to environmentally safe levels, but the remediation process will likely be in the magnitude of years for pastures with extremely high soil P. These options should be of interest to small poultry farmers who desire to use environmentally safe management practices to enhance the sustainabiltity of their farms.

Technical Abstract: A major use of manure generated on poultry farms has been as a fertilizer for pastures. A problem with this practice has been that high concentrations of phosphorus (P) in poultry waste has caused a buildup of soil P following long-term applications of manure. Excessive soil P has an environmental risk of escalating P in runoff to levels that can contaminate esurface waters. Although the remediation of soil P is a long-term process forage systems can be developed and managed to improve the uptake and utilization of soil P. Maximum annual distribution of growth can further be achieved by overseeding with cool-season annual grasses and legumes into warm-season perennial grasses. Cooler temperatures during the growing season of cool-season forages make it difficult to cure these forages; therefore, producing haylage will be necessary for obtaining acceptable yields during the cool season. In some situations, grazing with cattle ma abe the only alternative in utilizing cool-season forages, but P can be harvested in hay in the late season if cattle are removed in the early spring to allow for a late-season harvest. Management objectives of reducing soil P must be met through the development of intensively managed and utilized forage systems.