Submitted to: Mississippi Water Resources Research Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/6/2000
Publication Date: 8/1/2000
Citation: AIKEN, G.E., EDWARDS JR, J.H., POTE, D.H. 2000. COMBINING GRAZING AND HAY PRODUCTION FOR REMEDIATING SOIL P IN PASTURELAND OF THE SOUTHEAST U.S.MISSISSIPPI WATER RESOURCES RESEARCH CONFERENCE PROCEEDINGS. p. 314-319. Interpretive Summary: Confinement poultry and hog production are concentrated in the southeastern U.S., where it is typically combined with forage-based cattle production to make use of animal waste as a low-cost fertilizer for pastures and hay meadows. A problem with using animal waste as a fertilizer is that phosphorus is often applied in amounts that are above plant requirements. Therefore phosphorus accumulates in the soil to level that cause excessive runoff of phosphorus into waterways. Warm-season grass pastures can be intensively managed to improve the utilization and reduction of high soil phosphorus. Hay production of warm-season perennials is the most effective method of removing phosphorus from these pastures. Cool-season annual grasses can be overseeded into warm-season grass sod to increase the annual distribution of growth. Although cool and moist weather during the growing season prevents harvesting of hay until the late growing season, the pastures can be grazed with stocker calves to retain small amounts of phosphorus in growing body tissues. A late-season harvest of cool-season annual grasses can further improve the reduction of phosphorus during the cool season. This management strategy can be implemented for maintaining acceptable soil phosphorus levels or maximizing the reduction of soil phosphorus where environmentally unsafe levels exist. Furthermore, this strategy can be implemented as part of a waste management plan for small farms with both confinement and pasture production systems.
Technical Abstract: Animal waste is often applied as an organic fertilizer to bermudagrass and bahiagrass pastures in the southeastern U.S. Although the two perennial warm-season grasses respond well to the high nutrient concentrations of animal waste, phosphorus is often applied in amounts that are above plant requirements. High accumulation of phosphorus can cause excessive phosphorus in runoff. A forage system that combines the production of warm-season perennial grasses and cool-season annual grasses can be intensively utilized to maximize the uptake and removal of phosphorus from pastures with environmentally unsafe levels of soil phosphorus. Intensive hay production with bermudagrass can potentially remove 60 to 70 kg phosphorus ha-1 from the soil. Cool-season grasses can be heavily grazed by stocker calves to potentially remove 10 kg phosphorus ha-1 in growing body tissues. A late-season hay harvest can also potentially remove 10 to 20 kg phosphorus ha-1. Warm-season grass hay production can be combined with grazing and hay production of cool- season grasses in pastures with excessive phosphorus to expedite reduction of soil P.