Relationship between particle density and soil bulk chemical composition

An analytical database containing XRF chemical analyses and real density measurements of unconsolidated sediments of the Padania Plain (Northern Italy) has been used to understand the relationship that exists between the soil particle density (rho(s)) and their bulk chemical composition. Using a linear regression, we built an equation able to link the particle density with the soil elemental composition. Positive correlations were found between rho(s) and SiO2, MgO, CaO and Na2O and negative correlations with K2O, TiO2, Al2O3, Fe2O3 and LOI, reflecting the presence in the soils of quartz and feldspars/mineral clays respectively. Our equation is very useful because it helps to know the density properties of a soil when it is not possible to measure rho(s) with a pycnometer. On the other hand, by knowing the rho(s), it is possible to have a quite precise knowledge about the chemistry of the studied soils.