Soil-water interactions in shrink-swell clays: measurements and models across scales

Thursday, 18 December 2014: 9:45 AM
Ryan D. Stewart1, David Earl Rupp2, Majdi R Abou Najm3 and John Steven Selker2, (1)Virginia Polytechnic Institute and State University, Blacksburg, VA, United States, (2)Oregon State University, Corvallis, OR, United States, (3)American University of Beirut, Beirut, 1107, Lebanon
Shrink-swell clay soils, which are characterized by crack networks that form as the soil dries, are found all over the globe, with up to 350 million hectares being classified as either Vertisols or verticintergrades. When open, soil cracks can exert substantial influence on hydrological processes; however, up until now our ability to quantify and predict soil cracking behavior in real soils has been limited due to insufficient measurements and models.

Using measurements taken at multiple scales in the laboratory and in the field, as part of a long-term study, we have developed a new, parsimonious model that integrates the behavior of individual soil clods with plot- and catchment-scale processes such as infiltration and overland flow. Even though the model was developed for vertic soils, it potentially can be applied to other clayey soils in order to better describe common processes such as infiltration, preferential flow, and nutrient transport.