Development of Multi-Functional Heat Pulse Probe for Soil Monitoring of Natural and Managed Ecosystems.

The main objectives of this project is to develop a multi-functional heat pulse probe (MF-HPP) for simultaneous measurement of bulk soil thermal, water flow and solute transport properties, and to apply the HPP in root chamber experiments to measure and model root water and nitrate uptake in water-limited soil conditions. The HYDRUS-2D transport code was expanded, incorporating multi-dimensional root water and nutrient uptake under water-limited conditions. In addition, a more flexible computer model is being developed using COMSOL Multiphysics software that allows coupling of water, solute and heat transport for any 3-dimensional geometry of the HPP sensor. Various HPP proto types have been developed and tested, including those with wireless data transmission, to estimate soil water content, soil water fluxes, and soil salinity. In addition, we present the development of an in situ sensor using UV spectroscopy to measure soil solution nitrate to study plant nutrient uptake.