Atributos físicos e químicos do solo em três topossequências no cariri ocidental da Paraiba

Abstract

The soil originates from the union of the so-called formation factors where, an origin material will undergo active action of organisms and climate for a certain period of time in a topographical position (relief). These factors vary throughout the world and these variations over millions of years are primarily responsible for generating this diversity within ecosystems. Thus, the objective of this work was to study the physical and chemical attributes of the soil in three toposequences in western Paraíba. For this, three materials of different origins were selected (schist, gneiss, granite) and in each one a toposequence was made with three points (top, half slope and foothill), with the presence of lithosequence when compared in the same landscape conditions, however with materials from different origins, in each of the nine total points, 10 undisturbed samples and in a volumetric ring were collected. The depth was determined by the diagnostic horizon of each soil (approximately 10 cm), and these samples were analyzed and the physical and chemical attributes of the soil were determined. After obtaining the data, these were submitted to univariate analysis, simple regression analysis and multivariate analysis. The stability and consistency of these soils is complex and fragile, where anthropic actions need great attention and can cause great damage to this biome. The parent material was determinant in some chemical components of these soils, which are good from an agronomic point of view, but sensitive from an environmental point of view. Altitude is a fundamental factor in defining soil characteristics in western Cariri, reflecting on the soil-plant-atmosphere relationship. In relief positions, physically the top presents a more stable environment, while chemically the base has a greater interaction of attributes, in both cases related to water dynamics, both in cementation and in leaching, respectively. Shale soils, compared to gneiss and granite, are well-developed soils in the sertão of Paraíba, providing favorable physical and chemical conditions for agriculture, paying attention to salt levels in irrigation water.