Caracterização e classificação de solos desenvolvidos em cordilheiras do Pantanal do Miranda, Mato Grosso do Sul, Brasil

Abstract

The Pantanal is a landscape of great heterogeneity, with both terrestrial and aquatic environments. It has areas with small elevations in the terrain, called Cordilheiras that are 1 to 1,5 meters above the maximum flood level, it is a refuge for the terrestrial fauna during times of flood. The study area is located on Cordilheiras in the Miranda Pantanal. A profile was opened on the left bank of the Miranda River and another on the right bank of the Vermelho River. The Soils were classified according to the criteria of the Brazilian System of Soil Classification (SiBCS) as Chernossolo Typical Petrocalcicans. Carapaces of gastropods were collected in both profiles and dated by the 14C radiocarbon method. In Profile 1 a mollusk shell of the genus Pomacea sp. in the Bk horizon, with age of 3531 ± 27 AP, and fragments of shells of mollusks on the horizon C5, with age of 7032 ± 28 AP. In profile 2 was dated a gastropod shell of the genus also Pomacea sp. horizon A3, with age 1445 ± 26 AP. The profiles were classified in the archaeo-antroposol classification system proposed by Kampf et al. (2003), however it was only possible to fit them into the first categorical level given the lack of evidence of human occupation. The high levels of Mg2+ in the soil and in the petrocalcic horizons indicate that these were not only formed by the dissolution of the gastropod shells, but they may have influenced, however, it is necessary to perform other analyzes that prove the type of limestone forming the petrocalcium horizon. The presence of the gastropod shells is related to the high fertility of the studied soils, mainly with the presence of Ca2+ coming from the degradation of the shells and P due to the decomposition of the molluscs.