This thesis improves the characterization of unsaturated hydraulic properties for different types of peat and other organic soils at the laboratory and the field scale. First, suggestions for a general improvement of the unsaturated hydrological modeling in peatlands are made. Second, a novel one-dimensional expression for calculating specific yield for shallow groundwater systems with microrelief has been derived which was the basis for the development of a novel in situ method for determining soil water retention characteristics in shallow groundwater systems