Relação solo-paisagem em três topossequências sob diferentes materiais de origem na microrregião do cariri ocidental da Paraíba

Abstract

The semi-arid region has a geodiversity that produces an immense landscape mosaic, which favors a wide variation in soil cover, and this makes soil mapping difficult. Since, the detailed knowledge of soils is essential for the formulation of strategies aimed at their conservation. In this sense, comprehensive studies that address the soil-landscape parent material relationship can be efficient for pedological investigations in complex environments. Therefore, the objective of this work was to evaluate the soil-landscape source material relationships in three toposequences under metalimestone rocks, schist, migmatite, gneiss and granite in the Western Cariri microregion of Paraíba. In the toposequences, trenches were opened in strategic positions of the landscape and the morphological characterization of the profiles and the collection of samples by horizon were carried out. Next, physical, chemical and mineralogical analyzes were carried out. The profiles were morphologically described and classified according to the Brazilian Soil Classification System. In general, the soils showed a characteristic pattern of each class, in some positions of the landscape the influence of the source material was highlighted, but in general it was verified that the influence of the relief in the pedogenetic processes predominated. The granulometric analyzes revealed the predominance of the sand and silt fraction in most of the profiles, and the highest clay contents were found in the foothills and flat top positions. Chemical analyzes revealed that most soils have low acidity, low aluminum saturation, low base saturation (>50%) giving it the eutrophic character. The mineralogical analyzes confirmed the presence of considerable levels of primary minerals in the soils, and characteristics of the parent material. This study showed that a research approach integrating soil-landscape source material can be efficient to understand the pedological behavior in complex and dynamic regions.