Introduction of the Hungarian Detailed Soil Hydrophysical Database (MARTHA) and its use to test external pedotransfer functions

The Hungarian Detailed Soil Hydrophysical Database, called MARTHA ver2.0 has been developed to collect information on measured soil hydraulic and physical characteristics in Hungary. Recently this is the largest detailed national hydrophysical database, containing controlled information from a total of 15,005 soil horizons. Two commonly used pedotransfer functions were tested to evaluate the accuracy of the predictions on the MARTHA data set, representative for Hungarian soils. In general, the application of both examined pedotransfer functions (Rajkai, 1988; Wösten et al., 1999) was not very successful, because these PTFs are representative for other soil groups. The classification tree method was used to evaluate the effect of soil structure on the goodness of estimations. It was found that using the soil structure data the inaccuracies of soil water retention predictions are more explainable and the structure may serve as a grouping variable for the development of class PTFs