Management Dependent Properties and Pedotransfer Functions for Improving Map Unit Characterization of Select Southeastern U.S. Soils.

Temporal variability of near-surface soil properties is often management-dependent.  Soil Taxonomy was developed with emphasis on subsoil properties to reduce the impacts of management on taxonomic placement.  Although it is difficult to inventory near-surface soil properties in taxonomic-based soil survey applications, it is recognized characterization of the variability of these properties can greatly improve map unit interpretations.  Some degree of characterization of the management-induced range of near-surface soil hydraulic properties (infiltration rate, hydraulic conductivity, soil water retention) by map unit is necessary as these and related data are widely used. We collected near-surface (0-30 cm) soil physical and chemical data for soils in three Southeastern U.S. ecoregions (Appalachian Plateau, Gulf Coastal Plain, Tallahassee Hills) to better understand relationships between management, taxonomic based soil map units, and variability of hydraulic properties.  Soils range from Hapludults with loamy surfaces on the Plateau, to Pale- and Kandiudults with varying thickness of sandy eluvial horizons in the Coastal Plain. Continuous pedotransfer functions (PTFs) depicting soil hydraulic property variability using both inherent (e.g. soil texture) and dynamic (e.g. soil organic carbon, water stable aggregates, soil strength, water dispersible clay, etc..) soil properties were developed, and they described significant amounts of the hydraulic property variability within these map units (30 to 90%).  Efforts are currently emphasizing the development of improved approaches for efficiently characterizing management-induced soil hydraulic property variability in these and similar soils.