Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 1, 1998
Publication Date: N/A
Technical Abstract: Heavy or long-term application of animal wastes to soil can result in high soil P levels and increases the potential movement of P into groundwater. Undisturbed soil blocks (30 by 30 by 15 or 30 cm deep) were obtained from a long-term no-till corn field that received annual additions of cattle manure. P content (Bray 1) of the surface soil was 245 mg/kg, and at 30 cm mit was 37 mg/kg. The blocks received 3 simulated rains on separate days o 30, 45, and 45 min at 1 mm/min. Percolation was collected at the base of the blocks using a 64-cell grid lysimeter. With this macroporous soil, even at the wettest conditions, all 64 cells did not produce percolate during a single rain. In the first rain, average soluble P in the percolate was higher in the short blocks (4.8 mg/L) than in the deep blocks (2.9 mg/L). Concentrations of P in the percolate from the 15-cm deep blocks decreased as each rain progressed; the lowest average occurred with the third simulated rain (3.9 mg/L); P levels from the deep blocks were relatively stable within and among rains. This indicates that soluble P from a surface layer high in soil P can readily move through soil which is much lower in P.