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 […]

The content and shap of clay minerals are important in the definition of soil structure morphology. To evaluate the clay mineralogy and chemical properties of different aggregate size-classes of Latosols (Red-Yellow – LBd and Dusky Red – LVdf) derived from basalt in the state of Paraná, Brazil, soil samples of the Bw1 and Bw2 horizons were collected in four LBd and three LVdf profiles, distributed across two distinct toposequences. Dried and undisturbed soil samples were separated into six size-classes (2-4; […]

Two Oxisol (Red-Yellow Latosol LBw and Dusky Red Latosol LVdf) toposequences in Paraná State, Brazil, were evaluated regarding the effect of different relief positions and parent material on mineralogical characteristics of the soil clay fraction. The clay fraction was investigated by X-ray diffraction, differential thermal analysis, thermogravimetry, and chemical analysis. Total Si, Al and Fe contents were determined after clay sample digestion with a 3:1 mixture of 36% HCl and 68% HNO3 acids. The Fe and Al contents were determined […]