RT - Journal Article T1 - Performance of Eight Mathematical Models in Describing Particle Size Distribution of Some Soils from Charmahal-va-Bakhtiari Province JF - JSTNAR YR - 2011 JO - JSTNAR VO - 15 IS - 57 UR - http://jstnar.iut.ac.ir/article-1-1863-en.html SP - 63 EP - 75 K1 - Particle size distribution K1 - PSD models K1 - Fredlund model K1 - Soil texture. AB - Selecting an appropriate particle size distribution (PSD) model for a particular soil may be important for a precise estimation of soil hydraulic properties. Various models have been proposed for describing soil PSDs. The objective of this study was to compare the quality of fitting of eight PSD models (Fredlund, Gompertz, van Genuchten, Jaki, Logarithmic, Exponential, Logarithmic-Exponential and Fractal) in 71 soil samples collected from Lordegan and Saman in Charmahal-va-Bakhtiari province, Iran. Coefficient of determination ( ) and Akaike’s information criterion ( ) were used to compare the goodness-of-fit of the models to the experimental data. Results showed that Fredlund model is best for describing PSD of silt loam, silty clay loam, silty clay and sandy loam soil textures. While Fractal, Exponential and Logarithmic-Exponential models produced the poorest-fit in silt loam, silty clay loam and silty clay, they had the best performance in sandy loam texture. The performance of Fredlund and Gompertz models improved with an increase in clay and silt content from 25 and 40 percentage, respectively. The performance of Fractal, Exponential and Logarithmic-Exponential models improved by increasing the sand content. Reverse correlation was observed between silt content and the performance of the Fractal model. LA eng UL http://jstnar.iut.ac.ir/article-1-1863-en.html M3 ER -