Tomography of Soil Pores: from Morphological Characteristics to Structural–Functional Assessment of Pore Space

The development of tomographic studies of soil pore space in Russian soil science in 2011–2018 is discussed. In several years, these studies have evolved from the qualitative description of pores in some soils from the European part of Russia to the quantitative functional assessment of soil pore space on the bases of 3D tomographic models. Three stages of tomographic studies of soil pores can be distinguished: (1) qualitative analysis of pore space as a spatial-geometric characteristic of soil structure and as a component of the general analysis of soil morphology; (2) the obtaining of quantitative morphometric data on the shape, size, and orientation of soil pores and combined analysis of these tomographic data and data on the physical soil properties; and (3) the use of calculated tomographic parameters in the study of hydrological and physicomechanical properties of soils important for both theoretical and applied aspects of soil science. In recent years, the research has been focused on the assessment of the relationships between tomographic parameters of soil pore space and traditional soil hydrological constants, possibility of calculating the water retention curve and water conductivity function from the tomographic parameters of soil pore space, and on the quantitative assessment and prediction of soil degradation on the basis of tomographic data. The solution to these problems will make it possible to explain the physical phenomena controlling soil hydrological characteristics and to substantiate the use of tomographic data in applied soil science, soil hydrology, and agrophysics.