Soil genesis and classification in the environment “mar de morros” in the mid-valley of the river Paraiba do Sul, RJ
01/Aug/2010
Brazilian tropical soils are generally regarded as highly weathered, which is attributed to the climatic conditions (high temperatures and rainfall). However, in the “Mar de Morros” environment the intensity of pedogenic processes can be affected by the erosional removal of material, due to the hilly relief, which rejuvenates the surfaces. The objective of this study was to characterize and classify soil profiles in a toposequence developed from muscovite-biotite gneiss, located in the municipality of Pinheiral (Rio de Janeiro State). The […]
Relationship between soil, landscape and geological substrate of the sandy coastal plain of São Paulo state
01/Jun/2010
This paper presents the results of morphological properties and absolute dating by luminescence and 14C of 28 pedons from Quaternary marine deposits located in three counties along the coast in São Paulo State, Brazil: Bertioga, Cananéia, and Ilha Comprida. The objective was to provide evidence to elucidate the main processes of the genesis of Spodosols. This approach, which is unusual in research concerned with Brazilian Quaternary coastal plains, resulted in the following interpretations: (a) relief, hydrologic conditions and time were […]
Potassium-rich silicate rocks as plant nutrient sources
01/Jun/2010
This greenhouse study evaluated the effect of potassium-rich silicate rocks (alkaline ultramaphic, pyroclastic breccia and phlogopite) on the release of K and other chemical nutrients of the soil. A Yellow Latossol with 0.03 cmolc dm-3 K soil was used in the study. The rocks were tested at doses of 75, 150, 225 and 300 kg ha-1 K2O with and without lime, applied to increase the soil base saturation (V-value) to 70 %. The rock and lime materials were mixed with the soil in the pots, […]
Characterization and classification of soils developed from sandstone of the Aquidauana formation
01/Jun/2010
The Aquidauana geological formation consists of a set of up to 500 m thick sediments predominantly composed of sandstone with fine to medium grain size, interspersed with sandy conglomerates. In this environment, the topography is one of the main conditioning factors of the formation of different soil types in the landscape. The objective of this study was to characterize and classify soils developed from these sandstones. Four soils profiles along a representative toposequence of gentle slopes were sampled and studied. The […]
Soil spectral library and its use in soil classification
01/Jun/2010
Soil science has sought to develop better techniques for the classification of soils, one of which is the use of remote sensing applications. The use of ground sensors to obtain soil spectral data has enabled the characterization of these data and the advancement of techniques for the quantification of soil attributes. In order to do this, the creation of a soil spectral library is necessary. A spectral library should be representative of the variability of the soils in a region. […]
Spodosols pedogenesis under barreiras formation and sandbank environments in the south of Bahia
01/Jun/2010
Morphologically differentiated Spodosols usually occur in the Coastal Plain of the South of Bahia and North of Espírito Santo. They are found in profiles known as “muçungas”, i.e. sandy soils that accumulate water. In these areas, two kinds of Spodosols, different from those in the Restinga area, can be found: Spodosols with E albic horizon (white muçunungas) and without this horizon (black muçunungas). Eight soil profiles with spodic characteristics were collected and described in order to evaluate differences in the […]
Occurrence of silica bodies in surface horizons of soils in different ecosystems
01/Jun/2010
The understanding of the processes that cause the varied distribution of silica bodies in soils is essential for the interpretation of the possible environmental factors related to their stability, sediment deposition, paleosol formation and for the analysis of archaeological sites. Thus, this study had the objective of identifying and characterizing the silica bodies morphology from surface soil horizons collected at different terrestrial ecosystems. Samples of surface horizons were collected from 10 soil profiles and heated in a muffle furnace to […]
Soils in the Yanomami indigenous area in the mid-Catrimani River – Roraima
01/Apr/2010
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 […]
Mineralogy and micromorphology of cohesive horizons in oxisols and ultisols of the coastal tablelands of Alagoas, Brazil
01/Apr/2010
The cohesive character is a property of subsurface soil horizons with hard to extremely hard consistency when dry, and friable or firm when wet. Despite the agricultural importance, the formation of these horizons has not been fully explained. The objective of this study was a chemical, mineralogical and micromorphological characterization of cohesive soils of the Coastal Tablelands in Northeast Brazil, to understand their pedogenesis and identify properties for the definition of the cohesive character by the Brazilian System of Soil […]
Genesis and classification of Oxisols in a highland toposequence of the upper Jequitinhonha Valley (MG)
01/Feb/2010
The Brazilian System of Soil Classification (SiBCS) is a taxonomic system, open and in permanent construction, as new knowledge on Brazilian soils is obtained. The objective of this study was to characterize the chemical, physical, morphological, micro-morphological and mineralogical properties of four pedons of Oxisols in a highland toposequence in the upper Jequitinhonha Valley, emphasizing aspects of their genesis, classification and landscape development. The pedons occupy the following slope positions: summit – Red Oxisol (LV), mid slope (upper third) – […]
