Pedotransfer function for estimation of soil-specific surface area using soil fractal dimension of improved particle-size distribution

The specific surface area (SSA) of a soil is crucial for the interface of ions and water molecules with the soil particles. Therefore, many physical and chemical properties of a soil are determined using its total SSA. Measurement of SSA is time-consuming and laborious, and its estimation using pedotransfer functions is therefore preferred. The objectives of this study were to: (1) analyze the pore-solid interface fractal dimension (D) in soils with different textures from the southern part of Iran using estimated improved particle-size distribution (PSD) from the soil primary particles, i.e. clay, silt and sand; (2) develop a multivariate pedotransfer function to estimate D based on PSD; and (3) develop a multivariate pedotransfer function to link the values of D to the SSA. As a result, two pedotransfer functions are presented for estimation of D and SSA. To estimate SSA, the value of D is first obtained using the presented pedotransfer function and these estimated D values are then used in another pedotransfer function to estimate SSA. The pedotransfer functions were validated and it is concluded that they are able to predict the values of D and SSA accurately.