Alteration of soil hydraulic properties at the soil-root interface impact on soil water balance at the field scale

X-ray computer tomography enables a direct investigation of the soil-root interface in situ and thus a direct investigation of hydraulic parameters related to soil structure and pore size distribution. At the UFZ in Halle X-ray tomograph and a plant growth chamber are located next to each other which allows investigating the change of properties at the soil-root interface with time. Thus, this unique facility can be utilized for a systematic in situ investigation of different roots within a root system (tap roots versus laterals) and of plants differing in adaptation strategy to drought stress, root architecture and mucilage production. Experiments will be conducted in soils of different texture and clay mineralogy (i.e. different initial hydraulic properties) of which the hydraulic parameters will be determined separately (Multi-Step Outflow). Based on local bulk density the hydraulic parameters will be scaled for the interface and included into a 3D Model for the system based on Richards equation.