Prevention of phosphorus (P) losses from agricultural land to surface waters is critical to water quality issues such as eutrophication. Residual materials resulting from acid mine drainage (AMD) neutralization and other P-sorbing industrial byproducts (gypsum, flyash, and water treatment residuals) were evaluated for their ability to reduce available P concentrations in soil and manure. Materials were used in a P sorption isotherm at a material:solution ratio of 1:15 with concentrations of 0, 1, 5, 10, 25, 50, 100, 200, 400, 800, 1600, and 3200 mg P L-1, shaken for 16 h, and filtered before P analysis. Materials with 3200 mg P L-1 added were air dried and sequentially desorbed five times with deionized water, followed by solution P analysis. Samples from before and after sequential desorptions were chemically fractionated for P using the Hedley method. Manure P reduction was evaluated by conducting an isotherm involving the addition of each material to dairy, swine, and poultry manure at six different rates using a manure:solution ratio of 1:200 and shaking for 16 h before filtration and P analysis. Manure samples amended at the highest material rate and non-amended samples were chemically fractionated for P by the Hedley method. Each material's potential mechanisms for causing P reductions in both soil solutions and manures will be discussed. Differences with respect to the ability of each material to retain P based on material properties such as pH, calcium, iron, and aluminum content will be described.
See more of Phosphorus Chemistry in Soils: I. P Availability
See more of S11 Soils & Environmental Quality
See more of The ASA-CSSA-SSSA International Annual Meetings (November 6-10, 2005)