Dinâmica de serrapilheira e estoques de nutrientes, carbono e nitrogênio em solos de veredas na APA do Rio Pandeiros - MG

Abstract

Among the different physiognomic types of Cerrado vegetation there are the Veredas, wetland ecosystem associated with exudation of the water table and hygrophilous communities, which play a key role in the hydrological balance. Already, the adjacent environments to the veredas, called Cerrado environment, play an important role for the protection and maintenance of the entire ecosystem. In this sense, the objective of this study was to evaluate the dynamics of production, accumulation and decomposition of litter in the vicinity of the closed paths, as well as estimate the stocks of nutrients, carbon, and nitrogen of the soil ecosystem path with different stages of degradation. Three areas were selected in the EPA (Environmental Protection Area) of the Pandeiros River, located in the North of Minas Gerais, classified as preserved AD (Vereda água doce), with intermediate stage (Vereda Capivara) and advanced degradation (Vereda Buriti Grosso). For the collection of litter produced were randomly arranged 10 collectors in the intermediate range between savanna and palm swamp, and for the collection of litter accumulated on the ground was used a leaked feedback. Samples were collected monthly for a year to estimated rate of decomposition. Litter samples were randomly selected in the dry and rainy months for analysis as to chemical attributes. Soil sampling was carried out through trenches, open the edges of paths and parallel track in their surrounding savannas. Soil samples were taken at 0-10, 10-20 and 20-30, 30-40, 40-50, 50-75 and 75-100 cm depth to determine soil density, physical-chemical properties and carbon and nitrogen stocks in the soil. Most litter production during the dry season and the biggest accumulation in the soil occurred in the rainy season. Generally the litter decomposition rates of savanna environment of Freshwater, Capybara and Buriti Grosso were low, with values of 0.60, 0.53 and 0.41. These results can be attributed to the quality of the litter. Of the three areas, the preserved cerrado (Água Doce) was the one that had the highest decomposition rate, attributable to greater biodiversity decomposing soil organisms in this area. The nutrient content inproduced and accumulated litter on the ground in both seasons was decreasing in the following order: Ca> K> Mg> P. The most preserved area (Água Doce) showed the lowest carbon, nitrogen and C/N ratio in soil, both in the path and in the surrounding savannah. These stocks in the soil varied from 33.37 to 124.03 Mg ha-1 and 3.94 to 10.54 Mg ha-1, respectively, and the highest values among areas were found in Capivara and Buriti Grosso. These results occur due to human interventions that temporally raised the values in areas that currently are more degraded.