Variabilidade de goethita e hematita via dissolução redutiva em solos de região tropical e subtropical

Inda, Alberto Vasconcellos; Kämpf, N.

doi:10.1590/s0100-06832005000600003

Cited by 37 publications

(27 citation statements)

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“…Several authors have reported variations in the crystallographic attributes of iron oxides (Schwertmann & Kämpf, 1985;Schwertmann & Carlson 1994;Inda Júnior & Kämpf, 2005;Wiriyakitnateekul et al, 2007). These variations have been ascribed to the formation of iron oxides determined by the prevailing soil-environmental conditions (Schwertmann & Fischer, 1966;Torrent et al, 1982;Schwertmann & Murad, 1983;Kämpf & Curi, 2000).…”

Section: Introductionmentioning

confidence: 99%

“…In fact, environmental variations are known to lead to varying degrees of crystallinity of goethite and hematite. Also, hematite tends to have more uniform properties than goethite since hematite is formed from ferrihydrite in the solid state and goethite in the soil solution, which is why the influence of the particular environmental conditions on hematite is stronger (Schwertmann, 1985;Schwertmann & Taylor 1989;Singer et al, 1998;Inda Júnior & Kämpf, 2005). Variations in mean crystallite dimension were also observed for kaolinite and gibbsite.…”

Section: Introductionmentioning

confidence: 99%

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Mineralogy of the clay fraction of Alfisols in two slope curvatures: III - spatial variability

Camargo

Júnior

Pereira

2013

Rev. Bras. Ciênc. Solo

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SUMMARYA good knowledge of the spatial distribution of clay minerals in the landscape facilitates the understanding of the influence of relief on the content and crystallographic attributes of soil minerals such as goethite, hematite, kaolinite and gibbsite. This study aimed at describing the relationships between the mineral properties of the clay fraction and landscape shapes by determining the mineral properties of goethite, hematite, kaolinite and gibbsite, and assessing their dependence and spatial variability, in two slope curvatures. To this end, two 100 × 100 m grids were used to establish a total of 121 regularly spaced georeferenced sampling nodes 10 m apart. Samples were collected from the layer 0.0-0.2 m and analysed for iron oxides, and kaolinite and gibbsite in the clay fraction. Minerals in the clay fraction were characterized from their X-ray diffraction (XRD) patterns, which were interpreted and used to calculate the width at half height (WHH) and mean crystallite dimension (MCD) of iron oxides, kaolinite, and gibbsite, as well as aluminium substitution and specific surface area (SSA) in hematite and goethite. Additional calculations included the goethite and hematite contents, and the goethite/(goethite+hematite) [Gt/(Gt+Hm)] and kaolinite/ (kaolinite+gibbsite) [Kt/(Kt+Gb)] ratios. Mineral properties were established by statistical analysis of the XRD data, and spatial dependence was assessed geostatistically. Mineralogical properties differed significantly between the convex area and concave area. The geostatistical analysis showed a greater number of mineralogical properties with spatial dependence and a higher range in the convex than in the concave area.Index terms: iron oxides, kaolinite, gibbsite, goethite, hematite, relief.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mineralogy of the clay fraction of Alfisols in two slope curvatures: III - spatial variability

Camargo

Júnior

Pereira

2013

Rev. Bras. Ciênc. Solo

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“…The source material of the area consists of metagranites of metamorphic origin of Jurubatuba formation (Figure 1) of Proterozoic age, located in the central Brazilian plateau with gentle to corrugated terrain (IBGE, 2004). The primary vegetation is represented by savanna vegetation type of formation, Cerrado in the strict sense (IBGE, 2004;RIBEIRO, WALTER, 2008).…”

Section: Methodsmentioning

confidence: 99%

“…The primary vegetation is represented by savanna vegetation type of formation, Cerrado in the strict sense (IBGE, 2004;RIBEIRO, WALTER, 2008). Figure 1.…”

Section: Methodsmentioning

confidence: 99%

Characterization, classification and analysis of the main properties of the Southwestern Goias soil

Fernandes

Ribon

Marques

et al. 2016

SCA

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Characterization of the soil and the grouping of its properties through main component analysis can assist in the classification and observation of the consequences of the conversion of native forest areas in pastures. Such data can aid in management practices. Considering the lack of studies in Cerrado soils of south-western Goias, developed metagranites of Jurubatuba suite, the objective was to classify and study the physical, chemical and mineralogical soil (under native forest and pasture) Southwest of Goias. Soil sampling and classification followed the Field Methods Manual and the Brazilian System of Soil Classification, respectively. The physical, chemical and mineralogical soil were studied, as well as main component analysis made for these attributes. The profile 1 under native forest was classified as "Cambissolo Háplico Tb eutrófico latossólico". The profile 2 under degraded pasture was rated "Latossolo Amarelo eutrófico típico". In addition, the profile 3 under rotated pasture was rated as "Latossolo Vermelho eutrófico chernossólico". It was observed that the "Latossolos" have higher bulk density and soil penetration resistance, indicating greater soil compaction. They showed high amounts of iron oxides and minor amount of nutrients such as calcium and magnesium. The principal component analysis allowed the grouping of profiles into two groups. Group 1 brought together the properties related to "Latossolos", and the second was related to "Cambissolo" properties. Thus, the principal components analysis aids the understanding of soil properties and the grouping of soils with similar characteristics, the level of order and management. Key words: Cambissolo. Latossolos. Iron and aluminum oxides. ResumoA caracterização do solo e o agrupamento de suas propriedades por meio de análise de componentes principais podem auxiliar na classificação e na observação das consequências da conversão de áreas de mata nativa em pastagens. Tais dados podem auxiliar nas práticas de manejo adotadas. Considerando a ausência de estudos em solos do Cerrado do sudoeste goiano, desenvolvidos de metagranitos da suíte Jurubatuba, o objetivo deste trabalho foi classificar e estudar as propriedades físicas, químicas e mineralógicas de solos (sob mata nativa e pastagens) do Sudeste Goiano.

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“…The hematite/goethite mineralogical relation can be studied with remote sensing data, both multiand hyperspectral ones, that seek to spatialize the pedohydric character of an area, characterizing it as oxidation or oxidation of Fe +3 (Inda Junior & Kämpf, 2005;Camargo et al, 2008Camargo et al, , 2014Correa et al, 2008; Pesq. agropec.…”

Section: Introductionmentioning

confidence: 99%

WorldView-2 sensor for the detection of hematite and goethite in tropical soils

Baptista

Teobaldo

2017

Pesq. agropec. bras.

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-The objective of this work was to simulate the bands of the WorldView-2 sensor from laboratory specters, in order to study its potential to detect iron oxides, besides proposing a spectral index based on the depth of the spectral feature (RHGt Pf ). The iron index (IFe) and the hematite index (IHm), developed by Madeira Netto for bands of Landsat TM-5 sensor, were adjusted for WorldView-2 to test the potential of the new yellow band. The results showed that the yellow band degrades to 2% compared to the red one. This is due to fact that mineral quantification and identification are in the absorption feature, not in the reflectance one, and it is only improved in the visualization of color. A new spectral index, the RHGt PF , based on the depth feature with the continuum-removed spectra, was proposed, since the new bands of the WorldView-2 sensorthe coastal blue and yellow bands -allow a better individualization of the absorption features for goethite and hematite separately. The new index is statistically similar to the ratio Hm / Gt + Hm; however, it is not similar to the mineralogical relation obtained with Munsell colors.Index terms: mineralogical relation, remote sensing, spectral feature depth, spectral indices. Sensor WorldView-2 para detecção de hematita e goethita em solos tropicaisResumo -O objetivo deste trabalho foi simular as bandas do sensor WorldView-2 a partir de espectros obtidos em laboratório, para estudar seu potencial de detectar óxidos de ferro, além de propor um índice espectral com base na profundidade da feição espectral (RHGt PF ). O índice férrico IFe e o índice hematita IHm, desenvolvidos por Madeira Netto para as bandas do sensor Landsat-TM5, foram ajustados para o WorldView-2 para testar o potencial da nova banda do amarelo. Os resultados mostraram que a banda do amarelo degrada em 2% comparada à do vermelho. Isso se deve ao fato de a quantificação e identificação do mineral estarem localizadas na feição de absorção e não na de reflectância, e isso só é melhorado na visualização da cor. Um novo índice espectral, RHGt PF , baseado na profundidade de feição com o contínuo espectral removido, foi proposto, pois as novas bandas do sensor WorldView-2 -azul costal e amarelo -permitem individualizar melhor as feições de absorção da goethita e da hematita separadamente. O novo índice é estatisticamente similar à relação Hm / Hm + Gt; porém, ele não é similar à relação mineralógica obtida por meio das cores de Munsell.Termos para indexação: relação mineralógica, sensoriamento remoto, profundidade da feição espectral, índices espectrais.

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Variabilidade de goethita e hematita via dissolução redutiva em solos de região tropical e subtropical

Cited by 37 publications

References 28 publications

Mineralogy of the clay fraction of Alfisols in two slope curvatures: III - spatial variability

Mineralogy of the clay fraction of Alfisols in two slope curvatures: III - spatial variability

Characterization, classification and analysis of the main properties of the Southwestern Goias soil

WorldView-2 sensor for the detection of hematite and goethite in tropical soils

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