Characterizing Mass and Energy Transport at Different Vadose Zone Scales
This proposal seeks support to conduct physical characterizations of mass and energy transport occurring in the vadose zone (i.e., variably saturated soils) within the framework of the W2188 multistate project. Near-surface soils of the vadose zone sustain plants, mediate biotic and abiotic processes, and control mass and energy fluxes between atmosphere and groundwater. The vadose zone is a critical resource for agricultural ecosystems, and its sustainable use is key to the continued economic, social and ecological health in Idaho, the Pacific Northwest, the Intermountain West, and by extension, to all human life on Earth. However, our understanding of physical, biological and chemical processes within the vadose zone is limited by the ability to access and quantify static and transient soil physical properties. Such understanding is critical
to predict and mitigate likely impacts of increasing societal food and energy demands, as well as land use and climate change which impose ever greater stresses on the vadose zone and groundwater resources. Quantifying vadose zone processes is inherently complicated by natural heterogeneity and the disparity of scales across which controlling hydrological, geochemical, and microbiological processes dominate. Soil-water content is of primary importance given its influence on virtually all processes that govern flow and transport. Therefore, dynamics in water content may provide important information for improving the predictive understanding of complex dynamic subsurface systems. This proposal aims to characterize the spatio-temporal dynamics of soil-water content and the interactions between water content and plant communities at three different scales addressing the above issues. The
emphasis is on linking physical data and models with key soil physical, hydrological and ecological processes. An important part of the efforts are the development and application of novel techniques that will allow exploring the linkage between resource heterogeneity (soil texture, structure, water, aeration and nutrients) and plant response and community structures.