The most frequent soils in the coastal plain of the coast of São Paulo state are Spodosols, characterized by intense podzolization and the consequent presence of spodic horizon (Bh or Bhm). The podzolization process is characterized by the transport of organic matter (OM) in solution from the surface horizons to deeper soil, with or without iron and aluminum. Drainage can influence this process and is mainly related to the transport and accumulation of OM through the soil. In well-drained Spodosols the main movement is vertical, and development depth is limited by the depth of rain water penetration, where the B horizon tends to the accumulate OM in waveforms and follows the guidance of root penetration. In the poorly drained Spodosols, OM moves through the profile fllowing the water movement, both vertically and horizontally. On the southern coast of São Paulo state, Ilha Comprida is an example of a barrier island which, with its 74 km length and width ranging from 625 m to 5.37 km, has the remaining parts of the Pleistocene and Holocene sedimentation, vegetated by Restinga Forest. Spodosols occurence represents the diferentes types already described for the coastal plain of São Paulo. On the south side of Ilha Comprida is na rut exposed by erosion, in which is possible to view the large lateral variation of morphological Spodosols presents. This variation can be easily identified since the portion facing the Sea of Cananéia, where most of Spodosols remaining from Pleistocene with Bhm giants horizons, until the portion facing the ocean, where Spodosols have more incipient features of evolution, beyond Typical dune ridges. Due to the large variety of morphological features, representativeness and the easy access to Spodosols, allowing monitoration in detail of the lateral variation, this area was chosen for this study to elucidate some mechanisms related to the formation of these soils in coastal environments. The formation of Spodosols, especially with emphasis on molecular characterization of the MO have been poorly studied in tropical regions with scarcity of detailed studies that assess the characteristics and chemical composition of OM and its influence in the podzolization process. The main goal is to characterize the MO of Spodosols in order to obtain information about the chemical composition of organic substances that allow a more comprehensive approach on the formation processes and elucidate the lateral and vertical variation of OM evolution, and consequently, Spodic horizons in Ilha Comprida. After the partitioning of landforms along the transect of 2.7 km, will be described and designed soil horizons in representative segments to determine the choice of soil samples. To obtain information about the OM composition will be used analytical methods as pyrolysis associated to gas chromatography / mass spectrometry (Pi-CG/EM) and spectroscopic methods such as Nuclear Magnetic Resonance (NMR) for determining the properties of OM. Informations about the drainage network and the distribution of dissolved organic carbon (DOC) along the ground and sideways in landscape will be obtained.
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