Tuesday, November 6, 2007
199-7
Preferential Flow Patterns and Variability in Soil Phosphorus Profile Data in Selected West Virginia Benchmark Soils.
Michael Harman1, James Thompson1, E. M. Pena-Yewtukhiw2, and Stephen Carpenter3. (1) West Virginia Univ., West Virginia University, Po Box 6108, Morgantown, WV 26506, (2) Divison of Plant and Soil Sciences, 1104 Agricultural Sciences Building, West Virginia University, Morgantown, WV 26506-6108, (3) USDA-NRCS, USDA Natural Resources Conservation Service, 75 High St., Rm. 301, Morgantown, WV 26505
The long-term management of phosphorus (P) to maximize agricultural productivity while minimizing environmental loss is dependant on understanding the soil and P relationship. Preferential flow could impact the soil and P relationship. Preferential flow has been shown to move substances such as colloids and radionuclides through a soil profile while bypassing portion of the soil matrix. A similar movement of P could provide an additional mechanism for environmental loss. Our objective is to evaluate preferential flow potential, soil test P (STP) levels, and their interaction in pastures on selected benchmark soil series in West Virginia to further the understanding of the dynamic soil P relationship. Preferential flow potential was determined by dye applications and excavation to evaluate the infiltration patterns. To asses STP levels, soil samples were collected from each soil horizon of the exposed profiles in the stained and unstained soil matrix. Images of the dye stain patterns were processed using spatial analysis techniques to identify stained and unstained portions of the images and determine areas of preferential flow. STP levels were assessed with Mehlich 1 extractions. Preferential flow was observed in all series. STP levels decreased significantly from surface to subsurface horizons.