Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 29, 1999
Publication Date: N/A
Technical Abstract: Phosphorus buildup occurs in soils fertilized with poultry litter or swine effluent. Hay harvesting of forages is a management practice used to remove P from these soils. Plant P uptake varies among different forage species and among plant parts of these species. Uptake by leaves, upright stems, and flowers is useful since they can be harvested for hay and P removed from the site. Uptake by prostrate stems and roots ties up P but eventually they decompose releasing P to the environment. This study evaluated forage species for P accumulation in roots, stems, leaves, and flowers when grown under poultry litter or swine effluent fertilization. Phosphorus concentration and uptake was determined for plant parts of 17 grasses and legumes under poultry litter in Collins, MS; 13 legumes under swine effluent in Crawford, MS; and 3 bermudagrasses under swine effluent in Crawford, MS. Each study was conducted for 2 yr with single harvests of the annuals at full maturity and 5 harvests over 2 yr for bermudagrass. The majority of phosphorus in legumes, annual grasses, and bermudagrass was located in stems or runners. Legume stems had greater P concentrations than grasses, but grass stems contained more P due to their greater dry weight. Leaves contained about 25% of the plant P. Flowers and roots contained relatively little P. The P distribution in various plant parts varied greatly among forages, though stems usually contained the greatest P amount in all species. Due to the greater dry weight of stems, farmers should use management techniques to maximize stem production in their forages grown for hay to maximize P removal. Breeders should select forages with greater stem dry matter to increase P removal.