Mapeamento do potencial estoque de carbono nos solos da área de proteção ambiental sul da região metropolitana de Belo Horizonte

Abstract

Located within the geological and geomorphological compartment of the Iron Quadrangle, the Southern Environmental Protection Area of the Metropolitan Region of Belo Horizonte (APA SUL) is a sustainable-use conservation unit established to protect and conserve the natural systems necessary for maintaining biodiversity and the water resources essential for supplying the Belo Horizonte metropolitan region and its surroundings. Covering an area of 1,625 km², it encompasses the territories of thirteen municipalities, each characterized by distinct land uses and management practices. This study aimed to map potential soil carbon stocks within the Southern Environmental Protection Area (APA SUL) of the Metropolitan Region of Belo Horizonte (RMBH) and, consequently, to develop a mapping system capable of supporting territorial planning. Input data were obtained from field collections conducted by different authors, totaling 59 sampling points, as well as from environmental variables related to relief attributes (geomorphometric variables) and spectral attributes. Through regression modeling and a machine learning algorithm (Random Forest), it was possible to spatially identify the potential carbon stocks present in the soils of the study area. The results showed that the simulated values were close to those obtained in the field. Among the evaluated attributes, spectral correlation—specifically NDVI—showed the strongest relationship for estimating soil carbon stocks. Furthermore, soil organic carbon content, obtained through modeling, ranged from 4.37 g/kg CO to 57.29 g/kg CO, with the highest concentrations found in the central and eastern portions of the study area, partially encompassing the municipalities of Rio Acima, Caeté, and Santa Bárbara. In contrast, the lowest values, ranging from 4.37 to 19.46 g/kg, were observed in areas with steeper slopes, associated with the Serra do Curral, as well as schist and quartzite rocks and cerrado and/or grassland vegetation. This work made it possible to identifying areas with the greatest potential for soil organic carbon storage and, consequently, areas with higher conservation and management priorities.