Relação entre os elementos texturais do solo (areia, silte e argila), a biomassa de gramíneas e as fitofisionomias abertas do parque nacional da Serra da Canastra

Abstract

Cerrado is the second Brazilian biome with the greatest diversity of plant species and has been replaced by intensive monoculture cultivation, which causes economic vulnerability for the country and environmental degradation. Therefore, it is extremely important to understand the dynamics of their formations, as native vegetation informs sustainable adaptation modes that have been developed over thousands of years. The present work, carried out in the Serra da Canastra National Park, aimed to verify the relationship between the textural elements of the soil (sand, silt and clay), the grass biomass and the open phytophysiognomies of the Cerrado (Campo Limpo, Sujo and Savannah). It was expected that a greater amount of clay would be proportionally related to the biomass of grasses and the presence of larger vegetation, since the clay fraction of the soil allows greater retention of nutrients and water. An inversely proportional relationship was also expected with the amount of sand, which has little retention capacity. Thirty plots were randomly selected in the PNSC and 6 points were randomly selected within each of the five classes found (Argisol, Cambisol, Latosol, Neosol and Plintosol). The depth of soil collection was up to 10 cm. The samples were analyzed in the laboratory and the results found for the relationships between clay, sand and silt and grass biomass did not support the hypothesis that soil texture influences grass biomass (biomass ~ clay; R² = 0.07, p = 0.13), in relation to phytophysiognomies, the results showed that a higher percentage of clay tends to be related to the more open vegetation types in the areas of Cerrado in PNSC (i.e. grasslands) (R² = 0.72, p = 2.15e-08). The study shows the complexity of the relationships between edaphic texture and vegetation and the importance of understanding them better, as well as adding new variables to the discussion