Hydrophysical Characteristics of Sand Soils: Modeling the Restoration of Water-Retaining Capacity

Restoration of the water-retaining capacity of light soils was carried out according to semiempirical dependences of moisture conductivity on capillary pressure with their physical parameters in the regime of an unsaturated moisture content. The relationship between the granulometric composition and the intensity of moisture conductivity at different moisture values is investigated. Moisture conductivity as a hydrophysical characteristic reflecting the thermodynamic state of soil water is used in the calculation of parameters for empirical modeling. The obtained data were used for the restoration of the main hydrophysical characteristic by mathematical modeling using the semiempirical model of M. van Genuchten. Water retention curves are qualitatively similar for all soil types. The quantitative difference is due to the increase of the matrix potential during the transition from sand to loamy sand due to changes in the granulometric composition. The shift of water-holding curves in the direction of decreasing moisture was observed for the same soil potential. This indicates an increase in the water-retaining capacity as the soil weight and dust fraction increase.