Soil porosity prediction across Europe with a focus on soil particle density determination

This study emphasizes the critical role of soil porosity as an environmental variable influencing infiltration, compaction, runoff, and erosion, which are inversely related to bulk density. An analysis of topsoil porosity across Europe (0-20cm) was conducted using data from the LUCAS monitoring program, focusing on the fine earth fraction of soils. The conversion from bulk density to porosity – more intuitive for hydrological studies - requires knowledge of the particle density of both mineral and organic components, which is often lacking. A novel method was developed to estimate the particle density of organic matter using stoichiometric datasets from various land use types, resulting in an EU LUCAS average soil particle density of 2.53 g cm-3. The generated fine earth porosity map aligns with high porosity areas in Northern Europe's peatlands and Central Europe's forests, providing insights into soil densification processes linked to compaction from traffic or organic matter depletion due to land use changes. This understanding is crucial for assessing compaction and erosion risk.