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Do Aggregate Size Classes of the Subsurface Soil Horizon Have Different Chemical/Mineralogical Properties?

Rolff Vladimir Mitton, Vander Freitas Melo ORCID logo , Volnei Pauletti


ABSTRACT Variations in chemical and mineralogical properties of a soil can occur at short vertical and horizontal distances. The objective of the present study was to evaluate the chemical and mineralogical soil properties of different aggregate classes from young (Ustrochrept) and highly weathered (Acrustox) soils from the state of Paraná, Brazil. Undisturbed blocks (0.20 ×0.20 ×0.20 m) of soils were separated into aggregate classes: Acrustox – 8.0-4.0 mm; 4-2 mm; 2.0-0.5 mm; 0.5-0.2 mm; and <0.2 mm; and Ustrochrept – […]

Clay Mineralogy of Subtropical Soils under Long-Term Organic Fertilization in No-Tillage Systems

Fabrócio de Araújo Pedron, Cledimar Rogério Lourenzi, Carlos Aberto Ceretta, Juliana Lorensi, Adriana Cancian


ABSTRACT: Organic fertilization effect on physical-chemical properties in no-tillage systems in tropical soils has been widely investigated, but little is known about the effects of this practice on the mineralogy of the clay fraction. This study aimed to evaluate the clay-fraction mineralogy of two subtropical soils, fertilized with organic residues in long-term no-tillage systems. An Alfisol fertilized with 0, 40, and 80 m3 ha-1 yr-1 pig slurry was evaluated for eight years, and an Oxisol with 0, 8, and 16 […]

Identification of Heavy Metals in Crystals of Sand and Silt Fractions of Soils by Scanning Electron Microscopy (SEM EDS/WD-EPMA)

Araína Hulmnn Batista, Vander Freitas Melo, Robert Gilkes, Malcolm Roberts


ABSTRACT Studies of heavy metals are concentrate on clay fractions, but coarser fractions of the soil can constitute significant sources of structural forms of heavy metals. The aim of this study was to evaluate the occurrence of heavy metals in the structure of minerals of the sand and silt fractions of soils from three different parent materials (metamorphic rocks and granite) in southern Brazil using SEM/EDS – Scanning Electron Microscopy with Energy Dispersive Spectroscopy and with WD-EPMA – with Wavelength […]

Clay Mineralogy of Basaltic Hillsides Soils in the Western State of Santa Catarina

Jaime Antonio de Almeida, Janaina Corrêa, Catiline Schmitt


ABSTRACT A commonly accepted concept holds that highly fertile, shallow soils are predominant in the Basaltic Hillsides of Santa Catarina State, in southern Brazil, but their agricultural use is restricted, either by excessive stoniness, low effective depth or steep slopes. Information about soil properties and distribution along the slopes in this region is, however, scarce, especially regarding genesis and clay fraction mineralogy. The objective of this study was to evaluate soil properties of 12 profiles distributed in three toposequences (T) […]

Mineralogy of the Clay Fraction and Chemical Properties of Soils Developed from Sedimentary Lithologies of Pirambóia, Sanga-the-Cabral and Guará Geological Formations in Southern Brazil

Pablo Grahl dos Santos, Jaime Antonio de Almeida, Letícia Sequinatto


ABSTRACT Quali-quantitative and crystallographic characterizations of the different minerals of a soil are essential for the best evaluation of its genesis, degree of weathering, active pedogenetic processes, physical and chemical properties, and its potential reserve of mineral nutrients. This study presents the results of mineralogical investigations carried out to verify the influence of the different lithologies of three geological formations of a sedimentary nature on the mineralogical composition of the soils and the relation of this mineralogical composition to soil […]

Clay Mineralogy of Brazilian Oxisols with Shrinkage Properties

Samara Alves Testoni, Jaime Antonio de Almeida, Luana da Silva, Gabriel Ramatis Pugliese Andrade


ABSTRACT Shrinkage capacity (caráter retrátil in Portuguese) is a new diagnostic characteristic recently introduced in the Brazilian System of Soil Classification (SiBCS) to indicate shrink and swell properties observed in subtropical soils from highland plateaus in southern Brazil, specifically in Oxisols with brown colors. In soils located in road cuts exposed to drying for some weeks, strong shrinkage of soil volume is observed in these soils, resulting in the formation of pronounced vertical cracks and large and very large prismatic […]

Kinetics of Thermal Transformation of Synthetic Al-Maghemites into Al-Hematites

Adriele Galeti Nonaka, Marcelo Augusto Batista, Antonio Carlos Saraiva da Costa, Tadeu Takeyoshi Inoue, Taiana Gabriela Moretti Bonadio, Ivan Granemann de Souza


ABSTRACT Maghemite (γ-Fe2O3) and hematite (α-Fe2O3) are important iron oxides in Brazilian soils derived from basalt. Maghemite can transform into hematite when exposed to high temperatures. However, isomorphic substitution (e.g., Al3+) may largely influence this process. We analyzed the kinetics of thermal transformation of Al-maghemites into Al-hematites and some of its mineralogical aspects. Synthetic substituted maghemites with different degrees of Al-substitution (0.0, 1.0, 2.0, 2.9, 3.8, 5.6, 6.7, 10.0, 12.0, and 17.1 mol% Al) were subjected to a temperature of […]

Pedogenic Iron Oxides in Iron-Rich Oxisols Developed from Mafic Rocks

Danilo de Lima Camêlo, João Carlos Ker, Maurício Paulo Ferreira Fontes, Marcelo Metri Corrêa, Antonio Carlos Saraiva da Costa, Vander Freitas Melo


ABSTRACT Despite the considerable amount of information on the mineralogical characteristics of pedogenic Fe oxides in Brazilian soils, there are few studies on Fe-rich soils developed from mafic rocks with taxonomic identities at lower categorical levels. This study evaluated the mineralogical characteristics of pedogenic Fe oxides in B horizons (Bw) of Fe-rich Oxisols developed from several mafic rocks in the state of Minas Gerais, Brazil. The Bw horizons were sampled at a 0.8-1.0 m depth in 13 Ferric and Perferric […]

Thermal Transformation and Characterization of Synthetic Al-Substituted Maghemites (γ-Fe2-xAlxO3)

Adriele Galeti Nonaka, Marcelo Augusto Batista, Tadeu Takeyoshi Inoue, Antonio Carlos Saraiva da Costa


ABSTRACT Burning is a common practice in tropical areas and related changes in mineralogy might affect the chemical and physical behavior of soils. Maghemite is a common iron oxide in soils formed from basic rocks in tropical regions. This mineral and hematite are the main pigments in these soils and exhibit high magnetization stemming from the precursor magnetite formed during the weathering process of primary minerals. The objective of the present study was to analyze changes in color, magnetic suceptibility […]

Substitution of Clay Content for P-Remaining as an Index of the Phosphorus Buffering Capacity for Soils of Rio Grande do Sul

Douglas Antonio Rogeri, Clesio Gianello, Leandro Bortolon, Magno Batista Amorim


ABSTRACT Mehlich-1 soil extract is currently used in Rio Grande do Sul (RS) and Santa Catarina (SC) States, in Brazil, to evaluate soil phosphorus available to plants and Mehlich-1 is sensitive to soil buffering capacity. This limitation is overcome partly by soil separation into buffering classes based on soil clay content. However, soil clay content has some technical and operational limitations, such as the underestimation of soil clay levels in soils under no-till. The aim of this study was to […]