Pedo-transfer Function for Estimating Hydraulic Properties of Soils in Hilly Areas in the Upper Reach of the Yangtze River

【Objective】 Soil water retention curve (SWRC) is an important parameter for studying subsurface hydrological processes and solute transport in soils, but its direct measurement is labor-intensive. For large scale applications, it is often estimated indirectly using some easy-to-measure soil properties. In this paper, we propose a pedo-transfer function to estimate hydraulic parameters of the soils in hilly regions in the upper reach of the Yangtze River. 【Method】 Soil samples were taken from three land usages in the Yanting Wan’as watershed: paddy field, upland and forest. We measured their SWRC and other chemical and physical properties; the measured SWRC was fitted to the van Genuchten formula, from which we derived a pedo-transfer function to estimate the van Genuchten parameters using multiple stepwise linear regression analysis. Accuracy of the function was evaluated using the Pearson correlation analysis. 【Result】 ①Land use affects the ability of the soil to hold water. The land usage that affected wate