The objective of this study was to evaluate the physical, chemical, mineralogical and micromorphological characteristics of cohesive red, yellow and grayish soils in a toposequence of the Coastal Tablelands region in southern Bahia and northern Espirito Santo states. It was also sought to understand the mechanisms promoting their cohesion and fragipan formation. Therefore, the routine physical analyses, determination of the coarse clay/fine clay ratio, specific surface by BET-N2 and water vapor adsorption, magnetic susceptibility, scanning-electron microscopy analyses and the micromorphology […]

The objective of the present study was to make the physical and chemical characterization of soils developed on sediments of the Barreiras group, in southern Bahia, as well as soils formed from rocks of the crystalline basement, which were taken as reference. For this purpose, soil horizon samples from two representative toposequences of the Coastal Plain were selected and analyzed: (1) eutrophic argisolic Red Latosol, latosolic dystrophic Yellow Argisol, duric orthic Ferrocarbic Spodosol; (2) dystrophic abruptic Yellow Argisol, dystrophic typic […]

Nine profiles were studied along a toposequence developed on Barreiras Group sediments, in Fazenda Rio Negro, Entre Rios, Bahia, Brazil. Besides conventional analysis, an electromagnetic probe through GPR – Ground-Penetrating Radar was employed. The objective of this study was to analyze the use of this tool in the acquisition of information on features occurring underground, by comparing the radargrams and pedologic descriptions obtained in the area. The equipment used was a Geophysical Survey model, with an 80 MHz antenna. The […]

Fragipans and Duripans are frequently found in soils developed from sediments of the Barreiras Formation, in the low coastal plateaus of northeastern Brazil. Previous studies in arid regions have attributed Duripan cohesion to the amorphous silica. However, the Duripans and Fragipans in northeastern Brazil are located in semi-arid and high annual precipitation level zones (1.500 to 2.000 mm year-1). This study, based on a detailed characterization of soils from four depressions with different sizes, aimed to propose an evolution scheme […]

This study was conducted to examine the distribution and nature of Fe oxides in plinthic soils on the sediments of Barreiras Group (in the state of Piauí) and Itapecuru Formation (in the state of Maranhão) in Northeastern Brazil. Four pedons were selected: a “plinthic, dystrophic, epieutrophic Gray Podzolic with low activity clay” and a “dystrophic Plinthosol with low activity clay” (both Plinthic Kandiustalfs) on the Barreiras sediments, as well as an “eutrophic Plinthosol with low activity clay” and an “allic […]