Measuring and Modeling Macroporous Soil Water and Solute Flux Below the Root Zone of a Plano Silt-Loam Soil

With respect to protecting our ground and surface water resources, significant understanding of the importance of spatial and temporal variability of soil hydraulic parameters has been achieved and widely accepted. However, the need for developing and testing methods of accurately acquiring these parameters at the field and landscape scale still exists. One reason for the lag between accepting this significance and learning how to approach related management solutions is likely the cost of establishing robust instrumentation that allows distributed monitoring of realtime fluxes beneath the root zone. Such instrumentation would facilitate the development and testing of tools capable of quickly and accurately determining important parameters for predicting movement of water and solutes in the vadose zone. We are uniquely poised to conduct such distributed measurements with real-time resolution of subsurface water and solute fluxes by converting twelve 25 cm by 76 cm pan lysimeters that are already installed near the bottom of the rootzone of a corn field into water flux devices. Our goals with this proposal are to: 1) adapt 12 lysimeters to monitor water and solute fluxes in the subsurface of a corn field on a realtime scale, 2) conduct a series of experiments using these adapted lysimeters and study the distribution of vadose zone water and solute model parameters using a flexible computer package that contains multiple routines for coupling matrix and macropore flow, 3) develop and test two field methods for rapid assessment of the same soil properties, and 4) assess the ability of a simpler more easily parameterized model to simulate water movement through the vadose zone.