ABSTRACT Globally, soils with gypsic horizons cover approximately 1 million km², predominantly in arid climates. The formation of pedogenic gypsum in soils has been a topic of discussion in pedological studies for some time, with gypsification representing the process responsible for secondary gypsum accumulation. Even though international classification systems acknowledge the existence of gypsic horizons, there is a paucity of documented evidence concerning their occurrence in Brazilian soils. This study aimed to identify and describe a soil with secondary gypsum […]

ABSTRACT The northwestern part of the Acre State (Brazil) possesses singular soils in Brazilian Amazonia, but have been very little studied. This study aimed to discuss the genesis and some micropedological aspects of the soils from Serra do Divisor and adjacent floodplain soils of the Moa river, to enhance the knowledge on their formation. A toposequence of soils ranging from the uppermost part of sub-Andean Serra do Divisor to the Alluvial soils of Moa river floodplain was studied, regarding chemical, […]

ABSTRACT Information is scarce on the genesis and classification of soils derived from calcareous rocks in the Northeastern region of Brazil. This study describes the morphological, physical, chemical, mineralogical, and micromorphological properties of four soil profiles (P1-P4) located in the Apodi Plateau. A pedogenesis hypothesis and soil classification, according to the Brazilian System of Soil Classification (SiBCS), are proposed for these profiles. The interactions between parent material, surface topography and climate affected the pedogenesis processes and soil properties, although the […]

Integration of chemical extraction methods and X-ray diffraction can broaden understanding of K+ forms and reserves in soil fractions, and their potential release to plants. The aim of this study was to use chemical extraction methods to estimate mineral reserves of K+ in sand, silt, and clay from subtropical soils; to associate extraction mechanisms with the forms of K+ released; and to monitor the dynamic of K+ release in a kinetics study. The sand, silt, and clay fractions of the […]

The Archipelago of Fernando de Noronha (FN), Brazil, has poorly developed soils of the Cambisol, Vertisol, and Leptosol classes (WRB-FAO), with particular characteristics related to parent material of volcanic origin, a tropical climate with oceanic influence, and rolling to strongly rolling relief. The Vertisols of FN are formed from basic rocks, volcanic tuffs, and alluvial sediments. They are associated with depressed surfaces that have impeded drainage from the central highlands and coastal plains. In view of the need for environmental […]

Detailed studies of pedologic characterization, as well as of relationships between pedology, geology and geomorphology are important for the comprehension of the soil distribution in a landscape. The objective of this study was to evaluate the pedomorphogeological relationships in the Chapadas Elevadas of the Distrito Federal, by the chemical, physical, mineralogical and geochemical characterization of the soils found in this landscape compartment. Two representative top-sequences of the pedologic distribution were selected in this geomorphologic unit, whose soils were formed from […]

Soil mineralogy is an important tool to study and understand soil genesis and soil physical and chemical behavior. Furthermore, soil mineralogy is used as diagnostic criterion to define soil classes in the Brazilian System of Soil Classification and provides information on the potential soil mineral reserve of plant nutrients. In this context, this study presents the mineralogical characterization of gravel, fine and coarse sand fractions (under a binocular lens and petrographic microscope), and of the silt and clay fractions (by […]

Eucalypt root growth and yield are affected directly by soil compaction during forestry operations, particularly harvesting. These effects are intensified under high soil moisture conditions. An experiment was carried out under controlled conditions in order to evaluate the effects of compaction under increased soil moisture levels, on seedling growth and nutrition. An oxidic-gibbsitic Red Yellow Latosol (LVA) and a kaolinitic Yellow Latosol (LA) were used. The treatments consisted of five compaction pressure levels (0, 60, 120, 180, and 240 kPa) and […]

Soil color is one of the central attributes in soil classification because it is related to the organic matter content and iron oxide mineralogy. The objective of this study was to make an evaluation of the predictive capacity of soil color, as determined by diffuse reflectance techniques, to quantify hematite and goethite in different Brazilian latosols (Oxisols). The spectroscopy technique allowed separating yellowish and light colored samples from dark and red ones, indicating an increase in reflectivity with decreasing hematite […]

This work aimed to evaluate mineralogic transformations along pedogenetic alterations of soil profiles in the region of Lavras; Minas Gerais, Brazil, differentiated by acid, intermediate and basic geochemical composition of the parent material. Three profiles were selected: Profile 1 – Hapludult developed from granitic rocks (Granite from Itutinga); Profile 2 – Rhodudalf formed from dioritic rocks (Diorite from Rosário); and Profile 3 – Argiudoll formed from basic rocks of the Greenstone-Belt of Lavras. Along each soil profile, from the consolidated […]