Measurement and Simulation of Soil Water Dynamics Across a Small Agricultural Watershed.

Hydropedology has been identified as a “synergetic integration of soil science and hydrology” (Lin, 2012), which complements the SSSA motto, “Soils sustain life.”  Hydropedology implies spatial and temporal interactions between soil and water processes and state variables.  In the last decade, we have deployed sensors to infer space-time patterns of soil water content over a wheat field in Colorado, USA.  These data provide a basis for simulating soil water dynamics across a 56 ha watershed delineated by a surface runoff flume at the edge of the field and detailed landscape topography.  Soil textural and hydraulic properties have been measured in samples from profiles at different landscape positions.  The AgroEcoSystem (AgES) Watershed model is used to simulate surface infiltration, runoff, and stratified soil water responses.  Model parameters are calibrated using a Shuffled Complex Evolution scheme to capture complex process interactions in space and time.  Thus soil parameters are “inversed” to reveal spatial structure at the small watershed scale.  The soil structure and parameters are treated as static. However, the dynamic nature of soil properties (aka pedology) will be discussed as “next steps” in light of observed changes in soil surface elevation over a decade.  Therefore multiple facets of field measurement, biophysical process simulation, and information systems are invoked to integrate fundamentals of hydrology and soil science into hydropedology.

Reference: Lin, H. (Editor), 2012. Hydropedology: Synergistic Integration of Soil Science and Hydrology, Elsevier, Amsterdam, The Netherlands.