Atributos e classificação de perfil do solo em áreas de Caatinga no Semiárido da Paraíba.

Abstract

The soil is a constituent important that defines and distinguishes the landscape. The geological structures that characterize the semiarid region of the brazilian allow for the formation of soils with morphological characteristics differentiated. The Caatinga, in turn, is one of the brazilian biomes that have been modified over time by human action, being as yet little known in relation to their ability to store carbon. The work had as objective to characterize pedological the soils and to estimate the content of total organic carbon of the soil in the semiarid region of Paraíba, whose information will enable to establish the solution of problems related to the processes of the physical, chemical, and morphological, as well as in the systematization of management practices and the sustainable use of the soils of the region. The study was conducted in Tamanduá Farm, in the municipality of Santa Terezinha and Cachoeira of São Porfírio Farm, in the municipality of Santa Luzia, both in Paraiba State. To conduct the study were defined five areas, a selected area in the RPPN Fazenda Tamanduá, and the other selected on the Cachoeira of São Porfírio Farm, in areas with different stages of natural regeneration. The soil samples for the determination of the attributes of the morphological, physical and chemical profiles were taken from the trench is open in each area. For the chemical analyses, we determined calcium, magnesium, potassium, sodium, exchangeable and available phosphorus. In each area were marked, at random, four trenches (0.50 m x 0.50 m x 1.00 m), and the sampling performed in the dry season. Soil samples were collected for determination of soil density, moisture, and carbon stock, being held also evaluated the fertility and the class texture of the soil and the distribution of the biomass the root system in different depths. Thus, it is concluded that the morphological analysis of the profiles in the experimental areas allowed us to classify the soils in LUVISSOLO CHROMIC Pálico vertissólico (TCp), NEOSSOLO FLÚVICO Ta Dystrophic typical (RYd), NEOSSOLO FLÚVICO Ta Eutrophic typical (RYe) and CAMBISSOLO FLÚVICO Ta Eutrophic typical (CYe), in two areas. The largest inventory of total organic carbon was estimated in the area in the Initial Stage of Natural Regeneration (ISNR), with the highest values in the surface layers. As for the roots, the presence of thin roots in the soil profile evaluated was more intense in the superficial layer (0-10 cm).