Submitted to: American Forage and Grassland Council Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: March 15, 2004
Publication Date: June 14, 2004
Citation: Brink, G.E., Sistani, K.R. 2004. Phosphorus removal in forage systems. American Forage and Grassland Council Conference Proceedings. Technical Abstract: Manure management represents one of the greatest challenges for livestock producers, particularly where large numbers of animals are produced on a relatively small land area. Frequent application of manure at rates that supply most or all of the N requirement of a forage system can result in excessive soil P levels and increased risk of P loss to the environment. Forage crop production provides a means of removing P from soils and reducing the rate and extent of P accumulation, provided manure is applied when growing conditions are optimum. When fertilized annually with typical rates of broiler litter (4 tons/acre), swine effluent (4 acre-inches/acre), or dairy manure (15 tons/acre), P removal by temperate and tropical forages ranges from about 20 to 75 lb P/acre. Applying N fertilizer in addition to that supplied by the manure has the potential to increase P removal. Phosphorus removal rates of forage crops, however, are often a small proportion of that applied in the manure. To the maximum extent possible, producers should apply manure at rates that balance P application and P removal in the forage, and export the forage from the farm or feed it to animals that are not located on fields receiving manure.