Assessing the best performing pedotransfer functions for predicting the soil‐water characteristic curve according to soil texture classes and matric potentials

Abstract

AbstractThe soil‐water characteristic curve (SWCC) is a key input to many hydrological and water‐quality models that simulate water movement and solute transport in the vadose zone. Over the past four decades a considerable number of pedotransfer functions (PTFs) have been developed to predict SWCC. The goal of this study was to conduct a comprehensive evaluation of 30 PTFs, 11 discrete functions and 19 continuous functions. The SWCC predicted by different PTFs was statistically compared to SWCC measured for 2046 United States soils. The performance of each function was evaluated for soils of different textural classes and at four matric potentials: −4, −10, −33 and − 1,500 kPa. The results showed that for point PTFs, the PTF developed by Adhikary et al. (2008), was the best function to predict SWCC in very fine soils, whereas the PTF developed by Fooladmand (2011), showed the best performance in fine, medium fine, medium and coarse soils. For continuous PTFs, the PTF developed by Saxton et al. (1986), showed the best performance in very fine soil; the PTF developed by Cosby et al. (1984), showed the best performance in fine soil; the PTF developed by Rawls and Brakensiek (1985) showed the best performance in medium fine soil; and the PTF of Zacharias and Wessolek (2007), showed the best performance in medium and coarse soils. With respect to matric potentials, the PTFs of Gupta and Larson (1979), Dashtaki et al. (2010), and Hua et al. (2011), were the best performing point PTFs to predict SWCC at −4, −10, −33 and − 1,500 KPa, respectively. The continuous PTFs developed by Mayr and Jarvis (1999), Rosetta SSC (Schaap et al. 2001), Cosby et al. (1984), and Al Majou et al. (2007), showed the best performance to predict SWCC at −4, −10, −33 and − 1,500 kPa, respectively. The results of this study may be useful to hydrologic modelling as it identifies the most accurate PTF for each soil textural class and across the matric potential ranges.Highlights Performances of 30 pedotransfer functions of SWCCs were evaluated using soil database from the USA. The pedotransfer functions were classified into 11 point functions and 19 continuous functions. The pedotransfer functions were evaluated at five soil texture classes and four matric potentials Best‐performing pedotransfer functions were identified for each texture class and matric potential.