Atributos físicos, químicos e estoque de carbono em solos de uma topossequencia sob regeneração natural no Triângulo Mineiro

Abstract

This study aimed to evaluate the physical and chemical attributes of soil, as well as to quantify the total organic carbon content and carbon stock in different soil classes along a toposequence in the Triângulo Mineiro region, in the municipality of Uberaba, Minas Gerais, Brazil, in order to understand the spatial and vertical variability of these attributes and their interrelationships in soil quality. The studied toposequence was approximately 1,000 m long. The experimental design was a randomized complete block design with a split-plot arrangement, consisting of five soil classes: Oxisol (LV), Red-Yellow Oxisol (LVA), Cambisol (CA), Haplic Gleysol (GH), and Melanic Gleysol (GM), and two sampling depths (0.00–0.10 and 0.10–0.20 m), with five replicates. Physical soil attributes were evaluated, including bulk density, macro- and microporosity, total porosity, and aggregate stability and distribution, as well as chemical attributes related to soil fertility, such as pH and macro- and micronutrient contents. Total organic carbon (TOC) content and soil organic carbon stock (SOC stock) were also determined. The data were subjected to statistical analysis to identify differences among soil classes, sampling depths, and their interactions. The results showed that the hydromorphic soils, particularly the Melanic Gleysol (GM), presented higher total organic carbon contents and soil organic carbon stocks, which were associated with greater water saturation and lower rates of organic matter decomposition. In contrast, the Oxisols (LV and LVA) and the Cambisol (CA), located in higher and well-drained landscape positions, exhibited lower soil organic carbon stocks and better structural conditions. It was concluded that topography plays a decisive role in the distribution of the physical, chemical, and carbon-related attributes along the toposequence, highlighting the importance of this approach for sustainable soil management and land-use planning.