Relating Mass and Energy Fluxes to Arid Soil Development

The morphology of desert soil is linked to water flux through the soil system because terrain conditions are controlled, in large part, by soil hydrology. Furthermore, the accumulation and incorporation of clay, silt, calcium carbonate, and soluble salts, into soil horizons depend on the mass and energy balance of the soil. Most of our knowledge about desert soil formation, derived from many years of empirical field observations and conceptual model development, has been compiled closely with knowledge of Quaternary history and geomorphic processes. Recent research has focused on quantitative analyses of soil energy and mass balance using extensive field-based monitoring, an increasing array of soil hydraulic property characterization methods, and sophisticated multi-parametric, readily available, numerical models. This research has focused on several soil forming factors, including soil age, geomorphic position and proximity to desert shrubs, and at different spatial scales (point to basin). The results have highlighted the complex interrelationships between these environmental factors that are tied together by soil hydrology, and which in turn affect soil water balance and ecological functioning of desert landscapes. This presentation will highlight recent research findings that look specifically at the multi-scale, coupled processes that influence arid soil development in the Mojave Desert USA, with a specific emphasis on soil hydraulic properties. We will also describe future research to refine the development of the next generation of conceptual models of how desert soils form, including the recent construction of large (12m³) weighing lysimeters dedicated to the study of desert soil processes through the monitoring of soil water and energy transfer processes. Combining previous and future research efforts, we hope to further refine our understanding desert soil morphology, including the spatial distribution of soil and the diverse hydrologic behavior of various soil types.