Atributos químicos, físicos e morfológicos de solos em áreas degradadas pela exploração de madeira para lenha no semiárido da Paraíba.

Abstract

In the northeastern semiarid region to removal of vegetation mover has accelerated the process of soil degradation. The reversal of this process necessarily nvolves knowledge of the morphology and monitoring changes in chemical, physical and biological soir propertles. This study aimed to evaluate the chemical, physical and morphological attributes of soil in áreas intended for logging for firewood, in the semiarid region of the state of Paraíba. For this purpose, three sampling environments were defined: a) totally deforested área, b) totally deforested and burned área, and c) not deforested área. In each environment we selected a representative sample área of 70 x 50 m in which ave subareas (pseudoreplicates) 20 x 15 m, totaling 15 experimental plots were established. Soir samples (0-15 cm) in each plot was conducted in two collection periods (drought period and rainy season). Additionally, the opening of a trench was performed in each área, in order to morphological description and the physical and chemical analyzes of horizons and layers of each profile. From the results it follows that the profile of the native forest área was classified as Chromic Luvisols and proülle of deforested áreas deforested and burned and was classiüled as Entisol. The bolor of wet soil, the soir consistency and structure were the morphological attributes that showed greater variation and texture that less varied in the three profiles studied. In the three profiles studied have higher prevalence of calcium and magnesium cations over other cations, having these elements biggest contribution in the sum of bases and CEC, mainly in the subsurface horizons. In the three studied profiles, soil organic matter were considered low to verá low and the P contents were considered too low to medium The texturas class ranged from sandy loam to sandy frank, having the sand fraction predominated over the silt and day fractions in the studied profiles, this fraction nfluenced the density values obtained in soil surface horizons of three profiles evaluated. In deforested áreas of the semiarid Caatinga biome of Paraiba seasonality affects mainly the organic matter content and soil CEC. which decrease the rainy season. The physical attributes of the soir, the three áreas studied. especially the sand fraction, bulk density and particle as well as the total porosity, are little affected by seasonality.