Variabilidade espacial de atributos de qualidade do solo em uma toposseqüência sob pastagem no semiárido baiano

Abstract

Soil is an integral part of the environment and shows the combined effects of different factors: parent material, climate, organisms, relief and weather, in which actions and magnitude cause changes that is reflected in the characteristics attributes. Among the formation factors the relief stands out to be associated with spatial variability of important soil quality attributes. The study was carried out in soil under pasture, in Mombitaba farm, in Santa Ines – BA. The aim of this work was to evaluate the effect of the relief on the indicators and soil quality index, even as characterize spatial variability of saturated hydraulic conductivity and macroporosity on a toposequence located in the semi-arid region of Bahia. The following classes of soils were indentified: upper third, typical dystrophic Yellow Latosol; medium third, Ultisol; and in the lower third, Typical Tb Entropic Fluvic Neosol. The samples were collected from three grids of 6 x 22 m, with a regular distance of 2 m between points. It was found that the landscape influences the indicators chemists, physicists, QSI and main tasks, discriminating the potential and limitations of different classes of soils in the landscape. The composition of the global quality index (SQI) was influenced by relief, especially at the top and middle third, where, respectively, the predominant functions CAA and CRP. It was observed that the pattern of spatial variability, the extent and degree of spatial dependence were affected by the relief position, with differences between attributes. Regarding the observed K0 pure nugget effect, it is not possible to identify the structure of its variability and spatial dependence. As the MP observed pure nugget effect at the top with the spatial variability structure influenced by the relief in the middle and lower.