Variation of the kaolinite and gibbsite content at regional and local scale in Latosols of the Brazilian Central Plateau

Abstract

Mineralogy of the Latosols of the Brazilian Central Plateau remains under discussion in the absence of clear relationship with their age according to their geomorphic location. The aim of this study was thus to clarify the origin the kaolinite and gibbsite content variation by studying a regional toposequence and using data from the literature. Chemical composition and soil color were used to discuss mineralogy. The mineralogy of the clay fraction was also 2 discussed by using X-ray diagrams. Our results showed, that the large variation of kaolinite and gibbsite content can be explained by taken into account both their local and regional location, the variation of the hematite and goethite content remaining limited. The model that is proposed to explain such a variation combines a regional component which is mainly associated to the age of the geomorphic surface and a local component which is mainly associated to the hydraulic conditions along the toposequence.

Development and origin of the microgranular structure in latosols of the Brazilian Central Plateau: Significance of texture, mineralogy, and biological activity

“…2 and Table 1). Basic characteristics and hydraulic properties of these Latosols can be found in Reatto et al (2007) and data on the clay mineralogy of their Bw horizons in Reatto et al (2008). The Latosols L7 and L8 were studied by Volland et al (2004 and2005a) and are similar to those studied by Balbino et al (2001Balbino et al ( , 2002Balbino et al ( and 2004.…”

“…The Latosols studied showed a compound strong microgranular structure and weak to moderate medium sub-angular blocky structure independently of the landscape position on Tables Table 1 General characteristics of the Latosols (L) studied (modified after Reatto et al, 2007;Reatto et al, 2008) Table 2 Field morphological descriptions of the Latosols (L) studied Table 3 Physical and chemical characteristics of the diagnostic horizons (Bw) of the Latosols (L) studied Table 4 Micromorphological analyses of the diagnostic horizons (Bw) of the Latosols (L) studied Table 5 Mineralogy of the diagnostic horizons (Bw) of the Latosols (L) studied. Table 6 Volume of voids resulting from the assemblage of the microaggregates (inter-aggregates voids) for the Bw horizons studied.…”

Relationship between macrofauna, mineralogy and exchangeable calcium and magnesium in Cerrado Oxisols under pasture

“…kaolinitic and gibbsitic soils in the landscape. According to Reatto et al (2008), gibbsitic Oxisols -i.e. those of low R KGbare mainly located on the well-drained central part of the plateau.…”

Surface Complexation Modeling in Variable Charge Soils: Prediction of Cadmium Adsorption

“…Soil samples from the 0.00-0.20 m depth from 20 sites were collected and characterized for mineralogy, texture, organic carbon, and cation exchange capacity at pH 7.0 by Rein (2008); additional soils from horizons A and Bw from three sites were collected and characterized by Reatto et al (2007Reatto et al ( , 2008Reatto et al ( , 2009a. The characterization data, displayed in tables 1 and 2, were used in the present study.…”

“…The validation of the surface complexation models obtained with adsorption of Cd in 16 soil samples collected by Rein (2008) and six by Reatto et al (2008) was carried out using four soil samples from different localities (Sete Lagoas, São Gotardo, Uberaba, and Itumbiara), collected in a transect by Rein (2008). These four soil samples were not used during model prediction.…”