Indices of shape in the classification of soil structure
The aim of the study was to examine the usefulness of simple pore shape indices for the classification of soil structure with respect to two main groups of soil macropores (fissures and cavities). The samples were taken from various soils of SE Poland: Mollic and Eutric Leptosols, Eutric Regosol, Haplic Phaeozem, Haplic and Stagnic Luvisols, and Sapric Histosol. The research was performed on 81 polished blocks using image analysis. First, the soil samples were classified into five structural groups: mixed, fissure, nearly fissure, cavity and nearly cavity. Morphometrical analysis provided shape indices CIRav, ELGav, and their coefficients of variation V(CIR), V(ELG). They enabled the group of fissure structures to be distinguished from the groups of mixed, cavity and nearly cavity structures. The research may contribute to the creation of an objective method for recognising soil structure in respect to the main soil structure types: mixed (fissure-cavity), fissure and cavity structures.