资源环境科技发展态势分析平台

The soil properties of the upper soil layer determine the partitioning between infiltration, runoff, and evaporation, key processes related to soil agricultural and hydrological functioning. It is therefore important to have some information on these soil functions based on available and easy-to-measure properties. This study presents what we can learn a-priori from the soil water retention characteristic (WRC) on some important hydrological and agricultural functions. Based on a mathematical expression of the soil WRC, it is possible to estimate: the characteristic length, L_C, related to the disruption of hydraulic continuity of the water liquid phase in the soil; the saturated hydraulic conductivity K_s; the unsaturated hydraulic conductivity function of water and air, K(θ_w) and K(θ_a); the saturation degree S_eFC at field capacity and how long it will take to reach that state; the available water content in the soil, AWC; the capillary head at the wetting front, ψ_f; the infiltration capacity curve based on the Green and Ampt model, q_cap(t); the time to ponding, t_p, for any prescribed wetting rate; the cumulative water loss during stage-1 evaporation; the duration of stage-1 evaporation. All these a-priori estimates are valuable and sometimes necessary for efficient design and planning in agricultural and hydrological applications. The values of these estimates depend upon the specific mathematical expression chosen to represent the WRC.

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