Measurement of physical and hydraulic properties of organic soil using computed tomographic imagery

Defining and measuring the physical properties of peat is difficult but essential in order to accurately model the flux and storage of water in peatlands. The goal of this research is to develop a method to measure the physical and hydraulic properties of organic soil using computed tomographic imagery. Specifically, this research seeks to determine if two and three-dimensional images of peat, produced using a MicroCT scanner, can be used to accurately characterize air-filled porosity, active porosity, pore size distribution, pore saturated area and capillary films of porous Sphagnum cells at different soil tensions. Unsaturated hydraulic conductivity at similar soil tensions was also determined. Results indicate that the proportion of small air-filled pores in the peat sub-samples increased with increasing depth and unsaturated hydraulic conductivity was greater at deeper depths than shallower depths at equivalent soil tensions, suggesting this method is a potentially valuable tool for measuring peat properties.