Dissertations and Theses

Summary

Studies on soil genesis, distribution and behavior, common in other Brazilian regions, are very scarce in Amazon environments. Thus, the objective of this work was to determine soil-landscape relations in different physiographic regions of the medium Madeira river valley, south of Amazon state. The study also aimed to characterize and classify archaeological dark earths in this part of the Amazon basin. The work was carried out along three toposequences, typical of the main physiographic aspects of the region: low land/highland transition, grassland/forest transition and granitic rolling topography region. The toposequences were segmented in geomorphic surfaces and slope segments. Soil profiles were morphologically described at each slope unit and samples collected in all pedogenetic horizons. Besides the main profiles, 20 side samples were also collected in the surface and subsurface diagnostic horizons for statistical purposes. The soil profiles of the Archaeological dark earths were collected in the granitic sampling site. The samples were submitted to the following physical, chemical and mineralogical analysis: particle size analysis, soil and particle density, total porosity and hydraulic conductivity (physical); pH, exchangeable cations, available P, organic C, sulfuric attack, free iron oxides (chemical); X-ray diffraction analysis of sand, silt and clay fractions (mineralogical). All data was submitted to univariate and multivariate statistical analysis. The results showed that in the Amazon environments soil properties variation are strongly related with landscape. Landscape segmentation in geomorphic surfaces and slope units allowed the understanding of soil attributes variation and behavior.