Under field conditions in the Amazon forest, soil bulk density is difficult to measure. Rigorous methodological criteria must be applied to obtain reliable inventories of C stocks and soil nutrients, making this process expensive and sometimes unfeasible. This study aimed to generate models to estimate soil bulk density based on parameters that can be easily and reliably measured in the field and that are available in many soil-related inventories. Stepwise regression models to predict bulk density were developed using data […]

In Roraima, the spatial distribution of indigenous peoples indicates a background of constant search for soils capable of sustaining shift cultivation. This study aimed to establish a relationship between the understanding of soil by the Yanomami tribe from the mid-Catrimani river region and the Brazilian System of Soil Classification and evaluate the type of agricultural land use according to soil fertility tests, in two steps. The first consisted of visiting eight Indian communities to collect soil samples at 21 sites […]

Soil properties and characteristics are related to the quantity and type of minerals in the clay fraction. The objective of this research was to characterize the clay fraction and study the crystallographic characteristics of kaolinites in red and yellow soils, in support of further research on the relationships of this mineral with the characteristics and properties of the dominant soils in coastal tablelands. The following evaluations were performed: determination of the coarse clay/fine clay ratio; mineralogical analyses (qualitative and quantitative) […]

There have been several papers in the literature studying the genesis and consequences of particles cohesion in Argisols (Ultisols) and Latosols (Oxisols) from the Brazilian Inner and Coastal Plains. Just a few, however, provide insights into the clay fraction mineralogy, specially, the iron oxides complete characterization. The objective of this study was to investigate the chemical and crystallographic characteristics of iron oxides in red and yellow soils derived from the sediments of the Barreiras Formation or Pre-Cambrian rocks in the […]

Morphological, physical, chemical and mineralogical properties, as well as the weathering processes were studied in a Red Yellow Argisol (Aridic Kandiustalf) (well drained) and a Solodic Planosol (Aridic Haplustalf) (partially drained), developed from gnaisses, in a topossequence of the central semiarid region of Ceará State, Brazil. The study had the purpose of investigating the influence of soil locations in the landscape (internal drainage) and on the diversification of soil properties, as well as to study processes of surface transport and […]