A cobertura pedológica e suas relações com a gênese das depressões no terraço Taquarussu, MS, Brasil .

Abstract

In the southeast of Mato Grosso do Sul state, next to Parana river gutter, in a suface of about 2300Km2, called Taquarussu terrace, constituted by sandy materials of colluvio-alluvial deposit, that have a lot of depressions, most of them with water. As controversy about the origin and evolution of these depressions still persists, the methodology of the pedologic cover estructural analysis were applied, on the around of the depression that forms the lagoon Dos 32, with the aim of finding evidences demonstrating the internal mechanisms in soil, considering both pedogenetic and morphogenetic process in the origin and evolution of these forms. From the survey of the pedological cover, to systems were identified, one of them constituted by Latosol-Argisol-Planosol and another one by Planosol-Gleisol. In the pedologic system Latosol-Argisol-Planosol evidences were found, both morphological and analytical of the mobilization of material within the pedologic coverage. With the micromorphology, textural features of filling and covering were identified in the volumes that have higher levels of clay; changes in the color of the thin material next to the wall of tubular vertical void and; loss of material in the surface horizons Ap and E toward the downstream. The saturated hydraulic conductivity of soil showed levels that create impediment and delay of pores. The pedologic system Planosol-Gleisol demonstates a more aggressive dynamic in the removal of fine material within the pedologic cover in a small divider between two lagoons. From the evidences collected, it's possible to find the participation of the pedogenetics processes, especially in the expansion of the lagoons, but it also indicates the need for further studies to clarify the genesis and evolution of these depressions.