Effect of texture on the performance of soil particle-size distribution models

Particle-size distribution (PSD) of soils has been frequently used to estimate soil hydraulic properties. Various parametric PSD models have been proposed to describe a full range of the soil PSD from sparse experimental data. Nine PSD models were examined in order to determine the best model in representing the PSDs of 1385 Korean soils with textures ranging from sand to heavy clay. The coefficient of determination (r2) was used to measure the goodness-of-fit of the models and the Akaikeʹs information criterion (AIC) to compare the quality of model fits. Special attention was paid to the effects of soil texture on the performance of the models. The performance of the PSD models was affected by soil texture. The performance of most PSD models improved with the increase in clay content in soils. The Skaggs model showed better performance as the silt content increased. The Fredlund model was the best for describing the PSDs of clay, clay loam, loam, loamy sand, sandy clay loam, sandy loam, and silty clay soils, while two Skaggs models showed better performance for sand, silt loam, and silty clay loam soils.