A TOOL FOR MEASURING THE SHRINK/SWELL PHENOMENA OF PEAT GROWING MEDIA BY IMAGE ANALYSIS

摘要

By using a tool of image analysis developed in the laboratory, the study of the change in substrate volume during desiccation and rehydration was coupled to the measurements of the hydraulic properties (water retention curves, hydraulic conductivity & gas diffusivity). Results obtained on weakly decomposed peat showed an important shrink/swell phenomena with a change in total volume close to 20% from saturation to -20 kPa. Hysteresis was also highlighted, with largely different behaviours during desiccation then rehydration, but these phenomena seemed to be completely reversible.