Características do solo e estrutura fitossociológica de espécies arbóreas em dois cerradões no Triângulo Mineiro ; Soil characteristics and phytosociological structure of two cerradões in arboreous community in the Triângulo Mineiro

The study of cerradões is very important to improve knowledge phytosociological and edaphics characteristics physiognomy that significantly amended and fragmented. Given this reality, the objective of this study was to determine the phytosociological and soil characteristics of two fragments of cerradão located in Araguari and Uberlândia, MG. To achieve the phytosociological survey were sampled in each area all individuals with circumference at breast height (CAP) ≥ 15 cm in 25 plots of 20m x 20m. The percentage of canopy cover was estimated using a spherical densiômetro located in 38 points at the ends of the plots. As for the parameters edaphic, soil was collected from each plot at a depth of 0 to 20 cm in order to determine the pH (H2O), P, K1+, Ca2+, Mg2+, Al3+, Fe3+ and Mn2+, clay, silt, dense sand and fine sand. To verify the relationship between floristic plots was a Detrended Correspondence Analysis (DCA) and the relationship between the variables of soil and the distribution of species using a Canonical Correspondence Analysis (CCA). The soil under Araguari fragment is more clay, shallower and more nutrient content, while in Uberlândia is more gritty, deep and low in nutrients. Whereas the percentage of base saturation and the availability of Ca, the soil of the fragment Araguari was classified as mesotrophic while that of Uberlândia, dystrophic. The cerradão of Uberlândia presented greater coverage of canopy in the two seasons. As for phytosociological parameters in the fragment of Araguari were sampled 1,340 individuals belonging to 90 species, while in Uberlândia, 83 species distributed among the 1,797 individuals sampled. Fabaceae and Vochysiaceae families had the largest number of species in both areas. In Araguari species with the highest importance value were Terminalia argentea, Qualea grandiflora and Myracrodruon urundeuva while in Uberlândia, Sclerolobium paniculatum, Qualea grandiflora and Miconia albicans were the most important. The Shannon diversity index (H') in Araguari was 3.5 nats. ...