Wednesday, November 15, 2006

Preferential Flow and Phosphorus Translocation in West Virginia Benchmark Soils.

Michael B. Harman1, James Thompson2, and Eugenia Pena-Yewtukhiw1. (1) West Virginia Univ, Division of Plant and Soil Sciences, PO Box 6108, Morgantown, WV 26506-6108, (2) West Virginia Univ., West Virginia University, PO Box 6108, Morgantown, WV 26506-6108

The accumulation of phosphorus in some agricultural soils is an emerging problem, which can be more prominent in certain geographic regions associated with food animal agriculture production and on certain soil types.  In West Virginia, poultry litter, which is high in P (relative to N), is disproportionately produced in the Eastern Panhandle region of the state.  In this region, animal waste is often applied to the land using N-based nutrient management plans, which over time can lead to elevated soil test P levels.  Phosphorus movement in these soils could pose a risk to the environment if preferential flow is occurring and P is leaching or moving through the soil profile attached to colloids.  The objectives of this study are (i) to asses the occurrence of preferential flow within selected benchmark soil series, and (ii) to quantify the distribution of P through the soil profile.  In West Virginia, Grant, Hardy, and Pendleton counties have among the largest food animal agriculture production. Within these three counties, we will select benchmark soil series most commonly associated with hay and pasture land-covers and use this information to identify study sites with a history of land application of animal wastes.  Preferential flow potential will be determined by dye applications and excavation to evaluate the infiltration patterns.  Soil samples will be collected from each soil horizon of the exposed profiles in the stained and unstained soil matrix of each dye application, and from soil cores from the area surrounding the study sites.  Soil P levels will be assessed by Mehlich 1 extractions.  Our hypothesis is that (i) some degree of preferential flow will be identifiable within these series, and (ii) the highly adsorptive nature of the soil-phosphorus relationship will limit any translocation of phosphorus into subsurface horizons.