Hysteresis in the Desert Soils.

Mass and energy movement across the vadose zones influences water and solutes cycling and many biogeochemical processes, and there has been a disparity between the scale of measurement and the scale of interest due to the heterogeneity of nature. To better understand these processes in the desert environment, three lysimeters were constructed in Boulder City, NV, bridging research efforts at existing eco-scale, laboratory, and micro-scale research. In order to understand the mass and energy flow within the lysimeters, it is necessary to conduct a thorough investigation of the hydraulic properties of the porous medium inside. The objectives of this study are 1) to compare the soil water characteristic curves (SWCC) measured using Tempe cells, HYPROP, upward infiltration combined with HYDRUS 1D inverse parameter estimation, in-situ data analysis of heat dissipation units (HDU) and TDR sensors, and other pedotransfer function estimations; and 2) to determine the cost-benefit of using different approaches.