A Model for Predicting Packing Density of Soils Using Particle‐Size Distribution

Abstract

AbstractMany soil management decisions can be made from measured dry bulk density of the soil. These interpretations of soil behavior could be enhanced if soil particle‐size analysis could be used as a predictor of soil bulk density. A random‐packing model was developed utilizing soil‐particle size distribution as the principal input. Other inputs were average equivalent particle and cavity radii; bulk and particle densities of pure soil fractions determined under the same experimental conditions, like that of the final mixture; and concentrations of soil mineral and organic fractions. The model predicts random‐packing, maximum, and minimum bulk densities of a mixture of glass beads or soil fractions. Maximum and minimum bulk densities are limiting values not found in artificial or natural particle mixture. Tests of the random packing density with measured density showed a maximum deviation of 0.08 g/cm3 for multicomponent‐glass‐bead systems and 0.45 g/cm3 for mixtures of natural soil materials. Applications of the random‐packing model may delineate surface‐sealing susceptibility among soils of similar texture, describe the degree of profile devlopment among soils of different orders, and delineate soil profiles or horizons within a profile to pan formation susceptibility.