Mass fractal dimensions and some selected physical properties of contrasting soils and sediments of Mexico

The fractal approach to the study of soil structure, its dynamics, and physical processes appears to be a useful tool in reaching a better understanding of system performance. Nevertheless, the precise concurrent analysis of soil physical properties and fractal parameters seems to be important in order to evaluate the applicability of fractal concepts to soil science. The objective of this study was to relate the solid and pore mass fractal dimensions of some soils of Mexico to in situ measured bulk density, electrical permittivity and mechanical resistance. For this purpose, the fractal structure of some soils and sediments with contrasting physical properties is documented, using microscopic images, in the scale range from 0.009 to 0.2 cm. A single and statistically representative mass fractal dimension, independent of scale, was found for analysed solid and pore networks. Non-invasive techniques were used for in situ measurement of selected soil physical properties. The physical measurements were made simultaneously with sampling for the micromorphological analysis. Simple but not unique relations were established between the solid and pore mass fractal dimensions, soil bulk density, apparent dielectric constant (except for Eutric Vertisol), and mechanical resistance (except for Tepetates). A high correlation was found between mass fractal dimension and horizon depth. We conclude that the fractal analysis is a useful tool to distinguish between soils and sediments of different genesis, and that the solid and pore mass fractal dimensions may be useful indicators of the horizon compaction status.