Investigation of different models to describe soil particle-size distribution data

Particlesize distribution (PSD) is the most fundamental soil physical property, which has a distinct impact on other physical properties such as soil hydraulic properties As an input parameter for various simulation models, the accurate description of PSD is of vital importance to the reliability of simulation results In the present study, five empirical models, ie, the lognormal distribution, the cubic spline, the logistic growth, the modified logistic growth and the van Genuchten models, are employed to describe the cumulative particlesize distribution data from laboratory experiments, an international database and literature publicationsResults indicate that optimal agreements between measured and predicted values are obtained through the modified logistic growth model while the most frequently used lognormal model produces relatively poor agreements Furthermore, the other three empirical models are in between the aforementioned two models in terms of prediction accuracy Similar results are obtained in additional application of these models to estimate soil water retention characteristics using a fractal approach