Modelling and validation hysteresis in soil water retention curve using tomography of pore structure

Hysteresis in soil water retention curve (SWRC hysteresis) has a significant effect on soil water flow in unsaturated porous soils. The aims of the were to estimate wetting curve of the soil water retention curve based on drying curve and to study the reasons of hysteresis using tomography of pore structure. SWRC hysteresis was measured using capillarimeters for drying and wetting curves under a low soil potential. The proposed model αw = 2.5, αd was presented to calculate alpha of wetting curve (αw) based on alpha of drying curve (αd). The tomography method was used for describing the structure of porous space in the wetting and drying soils. Generally, the results of RMSE = 0.08 cm−1, GMER = 0.87, and Williams-Kloot test indicated that the proposed model can be used for estimation wetting curve under a low soil potential. Tomography of pore structure is a new technique used for describing the occurrence of hysteresis in SWRC.