Modeling of soil water retention curve using soil solid phase parameters

This paper presents the statistical–physical model (pedotransfer function) relating soil water content at defined values of soil water potential to selected parameters of soil solid phase, developed for eight arable soils representative for south-west Spain. The model contains two equations for which independent variables include the content of soil granulometric fractions 2.0–0.2 mm and 0.2–0.02 mm, and bulk density or total porosity. Similar correlation coefficients between measured and predicted water contents were found for both equations: 0.89 < R < 0.96 for the first and 0.88 < R < 0.96 for the second one. The model was validated for 46 Polish soils of a wide range of textures, yielding also good correlations of measured and predicted data (R values over 0.9 in both cases). That the model elaborated on the base of soil samples from mediterranean climate (Spain) was applicable for soil samples from temperate climate (Poland), proves its general usefulness for soil moisture content estimation from basic physical parameters of soil solid phase. The presented model is simpler than the other commonly used ones described in the literature.