Characterization of an ultisol using X-ray microtomography

The soil structure can be defined as the arrangement of soil particles and their porous space; it is important for the maintenance of porosity, aeration and growth of plants and microorganisms. The use of computerized X - ray microtomography promotes an advance in the study of the soil structure, making it possible to investigate the interior of the samples, keeping their shape, as well as the pore distribution, spatial configuration and how they are related to the behavior of the soil and its processes. This study aims to characterize an ultisol using microtomography, at a voltage of 150kV and a current of 226mA in an industrial scanner (XT H 225 ST, Nikon). The samples were obtained at the Várzea do Barro Farm in São João-PE, at three depths (0-7.5 cm, 10-17.5 cm and 21-28.5 cm). As a result, 3D tomographic images of the soils were obtained, in which the structures were analyzed at different depths, porosity and pore shape. We obtained a porosity of 43.42% for the depth of 0-7.5cm, 37.7% for the depth of 10-17.5 cm, and 28.77% for the depth of 21-28.5 cm. The pores presented a higher percentage of complex shape with a 78.45% (0-7.5 cm), 72.01% (10-17.5 cm) and 71.04% (21-28.5 cm); in the ellipsoid's shapes, were observed 7.54% (7-7.5 cm), 13.0% (10-17.5 cm) and 15.62% (21-28.5 cm). (author)