Soil pore system complexity and heterogeneity as affected by contrasting management practices

Abstract

To better understand the changes that occur in soil systems at different scales, researchers have been using concepts from the multifractal theory for investigating intricate and heterogeneous complex structures. This analysis has also been applied to understand how complex systems such as the soil behave under contrasting management practices. This study presents the use of the three-dimensional multifractal theory, lacunarity, and normalized Shannon entropy to characterize changes in the porous system of a Rhodic Hapludox under different management practices (conventional tillage, minimum tillage, and no-tillage) compared with the same soil under a secondary forest, assumed as a reference. The results of lacunarity and multifractal spectra revealed separations between management groups in relation to their porous systems (secondary forest with no-tillage and conventional tillage with minimum tillage). These results indicate possible “degradation” in the structure of the soil under conventional and minimum tillage and its preservation when under no-tillage as the complexity of their pores is analyzed. The contrasting management practices and forest presented linear correlations between soil porosity and lacunarities, maximum normalized Shannon entropy, and the multifractal spectra. The degree of multifractal spectra asymmetries and lacunarities evidenced the variability of spatial distributions of the managements and forest pore size diameters, showing that these tools are useful for characterizing the soil pore system. The results obtained showed the potential and sensitivity of the 3D multifractal approach in the characterization and differentiation of complexity in soil management practices.