Chemical, physical and mineralogical attributes of soils derived from sedimentary rocks of the Planalto of Lages-SC, Brazil

Abstract

In the Southern Plateau of Santa Catarina state, Brazil, corresponding to the Lages region and surrounding municipalities, there is little detailed information on developed soils of gonduan sedimentary rocks, which dominate in most of these municipalities. The study aimed to characterize the physical, chemical and mineralogical properties of five soils developed from sedimentary rocks of the Lages-SC region, derived from different geological formations, as well as to relate the mineralogy of the clay fraction with the chemical attributes of these soils. For this, samples of horizons and layers of five soil profiles were described and collected, being four Cambissolos (Umbrisols and Cambisols) and one Neossolo (Regosols). Chemical, physical and mineralogical analyzes of each soil profile were performed. The mineralogy of the clay fraction, besides indicating the predominance of 2: 1 clay minerals associated or not with hydroxy-Al polymers interlayered in three of the five soils (profiles 2, 3 and 4), was also related to the acidity and the main chemical properties of soils. All the studied soils are very acidic, with low sums and base saturation, high contents of total organic carbon, Al exchangeable and Al saturation. Clay contents were higher in soils derived from shales (Palermo and Teresina Formations) in relation to the others.