抄録
In this study, soil surveys and water retention measurements were conducted on a wide range of soil textures sampled from thirty one locations in the central hinterland of Horqin sandy land. Because the measured water retention curves belong to intermediate scanning curves between the main desorption and sorption processes, some precautions on measurement and application of the water retention curves were suggested. All soils in survey sites were classified into nine soil types. The average water retention curve of each soil type could be sufficiently approximated by using van Genuchten formula (vG-I). Their saturated and residual volumetric water contents (θs, θr) increased with clay contents of soil groups. It was confirmed that the shape of their water retention curves are reflected precisely by the parameters ε and ν that describe the degree of the first and second inflection curvatures of vG-I, respectively. Pedotransfer functions in the survey area were estimated using the water retention curves for the nine soil types by the function parameter regression method. The parameters of the fittedwater retention curves using vG-1 and vG-II (assumed m =l in vG-I)were known to have quite good regression relations with the indexes of soil physical and chemical properties. Particularly, the accuracy of estimation was found to increase when the regression formulas of ε and ν were substituted for m and n in vG-I. Therefore, PTF is an efficient method for estimating the water retention curves for different sites in the survey area.
