Capability of different interpolation models and pedotransfer functions to estimate soil hydraulic properties in Büyükçay Watershed

Many catchment basins have insufficient data to make conservation planning for sustainable natural resources use. In addition, intensive soil sampling is neither feasible nor economical in a large studied area. Therefore, interpolation models and pedotransfer functions (PTFs) have important roles in data mining. Main objectives of this study were to estimate and evaluate the estimates of basic soil hydraulic properties in Büyükçay Watershed (Turkey) using different interpolation geostatistic models and PTFs. Three interpolation models (inverse distance weighting IDW, ordinary kriging and cokriging) and pedotransfer functions (continuous and class) were applied and compared in this study. In 84 soil samples, soil depth, texture, organic matter, pH, electric conductivity, saturation degree, field capacity and permanent wilting point were determined. According to the results, among geostatistical algorithms, ordinary cokriging yields better results for all soil hydraulic properties with lower MAE and MSE values than ordinary kriging and IDW. Within PTFs, soil hydraulic properties were estimated with high reliability using continuous approach; however, class PTFs showed less sensitivity to space variability than geostatistical methods.