Morphometric profiles of pore space in loamy soils of the forest and steppe zones of European Russia

A computer-based image analysis of vertically oriented thin sections was applied to study changes in the shape and orientation of fine soil macropores (d = 0.2−2.0 mm) in the profiles of soddy-podzolic soils and typical (migrational-mycelial) chernozems. Generalization of the obtained morphometric data was based on the theory of mereology, a scientific discipline studying the structure (part-whole relationships) of classified objects. As a first approximation, generalized data characterized archetypes of morphometric porespace profiles of the studied soils. The archetype of the pore-space profile of the soddy-podzolic soil consists of four components (meronyms) corresponding to the humus-accumulative, eluvial, textural (clay-illuvial), and transitional to the parent material (BC) horizons. Sharp boundaries between the upper horizons specify sharp changes in the studied meronomic indices of the shape and orientation of soil pores. The pore-space profile of the migrational-mycelial chernozem consists of two major components: specific pores in the granular dark-humus (AU) horizon and complex pore space of the BCA and BCca horizons that are poorly differentiated with respect to the shape and orientation of their fine macropores despite clear genetic differences between these horizons. Pore-space patterns in the lower (transitional to the parent material) horizons of the studied soils are characterized by the high degree of similarity (>75%). Pore-space patterns in the upper horizons of the studied soils are different; the level of their similarity does not exceed 24–41.5%. The results obtained in this study hold promise in the use of morphometric characteristics of the pore space in separate genetic soil horizons as meronyms composing archetypes of the pore-space profiles of different soils. Such archetypes may be used for diagnostic purposes as reference pore-space profiles of the particular types of soils.