RESUMOAs turfeiras são Organossolos que resultam de condições ecológicas ideais ao acúmulo de material orgânico, controladas pelos sistemas geomorfológicos e processos geológicos e climáticos globais. Sua constituição física, química e biológica é pouco conhecida. No presente trabalho foi realizado um estudo sobre as turfeiras da Serra do Espinhaço Meridional (SdEM) -MG, por meio da descrição e coleta de amostras em três perfis situados a 1.250 m (P1), 1.350 m (P4) e 1.800 m (P2) de altitude. Os três perfis foram caracterizados morfologicamente e, nas amostras coletadas, foram realizadas análises químicas e fracionamento da matéria orgânica em ácidos húmicos, ácidos fúlvicos e humina. A matéria orgânica dos perfis de Turfeiras da SdEM apresentou marcantes diferenças entre si em relação à sua composição química e ao teor das substâncias húmicas e à composição química dos ácidos húmicos. A variação das condições de drenagem foi preponderante para a diferenciação qualitativa e quantitativa da matéria orgânica. A turfeira P1, com moderadas condições de drenagem, apresentou matéria orgânica com maiores relações C/N e O/C, predomínio de ácidos fúlvicos entre as substâncias húmicas e ácidos húmicos e elevada relação C/N. Nas turfeiras P2 e P4, com muito más condições de drenagem, as relações C/N e O/C da matéria orgânica foram mais baixas, a humina predominou amplamente entre as substâncias húmicas e os ácidos húmicos apresentaram a mais baixa relação C/N. Termos de indexação: Organossolos, matéria orgânica do solo, ácidos fúlvicos, ácidos húmicos, humina.
José ricardo da rocha campos (2) , alexandre christófaro silva (3) & pablo Vidal-torrado (4) suMMarY peatlands form in areas where net primary of organic matter production exceeds losses due to the decomposition, leaching or disturbance. due to their chemical and physical characteristics, bogs can influence water dynamics because they can store large volumes of water in the rainy season and gradually release this water during the other months of the year. in diamantina, Minas gerais, Brazil, a peatland in the environmental protection area of pau-de-fruta ensures the water supply of 40,000 inhabitants. the hypothesis of this study is that the peat bogs in pau-de-fruta act as an environment for carbon storage and a regulator of water flow in the córrego das pedras basin. the objective of this study was to estimate the water volume and organic matter mass in this peatland and to study the influence of this environment on the water flow in the córrego das pedras basin. the peatland was mapped using 57 transects, at intervals of 100 m. along all transects, the depth of the peat bog, the universal transverse Mercator (utM) coordinates and altitude were recorded every 20 m and used to calculate the area and volume of the peatland. the water volume was estimated, using a method developed in this study, and the mass of organic matter based on samples from 106 profiles. the peatland covered 81.7 hectares (ha), and stored 497,767 m 3 of water, representing 83.7 % of the total volume of the peat bog. the total amount of organic matter (OM) was 45,148 t, corresponding to 552 t ha -1 of OM. the peat bog occupies 11.9 % of the area covered by the córrego das pedras basin and stores 77.6 % of the annual water surplus, thus controlling the water flow in the basin and consequently regulating the water course. index terms: histosols, water retention, water flow.
SUMMARYIn the region of the Serra do Espinhaço Meridional, peat bog is formed in hydromorphic environments developed in sunken areas on the plain surfaces with vegetation adapted to hydromorphic conditions, favoring the accumulation and preservation of organic matter. This pedoenvironment is developed on the regionally predominant quartzite rocks. Peat bog in the Environmental Protection Area -APA Pau-de-Fruta, located in the watershed of Córrego das Pedras, Diamantina,Brazil, was mapped and three representative profiles were morphologically characterized and sampled for physical, chemical and microbiological analyses. The organic matter was fractionated into fulvic acid (FA), humic acids (HA) and humin (H). Two profiles were sampled to determine the radiocarbon age and δ δ δ δ δ 13 13 13 13 13 C. The structural organization of the three profiles is homogeneous. The first two layers consist of fibric, the two subsequent of hemic and the four deepest of sapric peat, showing that organic matter decomposition advances with depth and that the influence of mineral materials in deeper layers is greater. Physical properties were homogeneous in the profiles, but varied in the sampled layers. Chemical properties were similar in the layers, but the Ca content, sum of bases and base saturation differed between profiles. Contents of H predominated in the more soluble organic matter fractions and were accumulated at a higher rate in the surface and deeper layers, while HA levels were higher in the intermediate and FA in the deeper layers. Microbial activity did not vary among profiles and was highest in the surface layers, decreasing with depth. From the
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