Sistemas Agroflorestais no Cerrado: Impactos na qualidade do solo e na conservação de espécies medicinais nativas em Assentamento de Reforma Agrária

Abstract

Environmental degradation and biodiversity loss in the Brazilian Cerrado call for alternatives that reconcile conservation with socioeconomic viability. Agroforestry systems (AFSs) have emerged as sustainable practices capable of integrating tree, legume, grass, and medicinal species, promoting nutrient cycling, improving soil structure, and enhancing productive diversification. The objective of this study was to establish and evaluate a demonstrative agroforestry system (AFS) unit in the Canudos Settlement, in the municipality of Palmeiras de Goiás (GO), as a strategy for the conservation and adaptation of native Cerrado species, considering plant survival and growth, the production and quality of biomass from green manure species, as well as changes in the chemical, physical, and biological attributes of the soil. The study was conducted between 2023 and 2025, using intercropping arrangements of Poaceae and Fabaceae in different proportions, associated with medicinal species. Survival rates and plant height, green and dry biomass, chemical attributes (macro- and micronutrients, organic matter, pH, and cation exchange capacity), physical attributes (bulk density, total porosity, macro- and microporosity), and biological attributes (enzyme activities and soil quality indices) were evaluated. The results showed high survival rates (average of 80%), with Morus nigra (100%) and Cymbopogon flexuosus (94%) standing out. Species such as Varronia curassavica and Melaleuca lanceolata also showed good performance, whereas Lafoensia pacari and Pelargonium graveolens exhibited lower adaptation. Regarding biomass production, melaleuca and alecrim-pimenta showed stability, while L. pacari presented significant differences, highlighting the relevance of legumes to productive performance. In terms of soil attributes, increases in organic matter, phosphorus, calcium, and potassium were observed, along with higher cation exchange capacity in the 0–20 cm layer. Bulk density decreased, while total porosity and macroporosity increased, favoring water infiltration and root development. Microporosity showed gradual growth up to 2025, indicating greater water retention capacity. Biological attributes reinforced the superiority of diversified arrangements, especially those composed of 70% Fabaceae and 30% Poaceae, which presented the best biological, chemical, and functional soil quality indices, in some parameters even surpassing those of native Cerrado vegetation. It is concluded that the implemented AFSs promoted environmental and productive improvements without signs of soil degradation, while strengthening family farming and the protagonism of the Mulheres Guerreiras de Canudos group, contributing to productive diversification, income generation, and food security. The established demonstrative unit becomes a reference for the dissemination of agroecological practices in the Cerrado, combining environmental conservation, productive innovation, and community development.