ABSTRACT There has long been a discussion about the effects of soil management on its structure. Since changes can occur due to management and time of use, more accurate assessments can be achieved if carried out in long-term experiments. This study investigated the long-term effects of soil management on the physical quality of a Cerrado Oxisol (Latossolo Vermelho), focusing on microstructural changes. Micromorphology and computed tomography techniques were used to assess the soil’s microstructure. The study compared areas under long-term […]

ABSTRACT Information is scarce on the genesis and classification of soils derived from calcareous rocks in the Northeastern region of Brazil. This study describes the morphological, physical, chemical, mineralogical, and micromorphological properties of four soil profiles (P1-P4) located in the Apodi Plateau. A pedogenesis hypothesis and soil classification, according to the Brazilian System of Soil Classification (SiBCS), are proposed for these profiles. The interactions between parent material, surface topography and climate affected the pedogenesis processes and soil properties, although the […]

Despite their importance and vulnerability, little is known about the soils in the calcareous karst systems in Brazil. The objective of this study was to evaluate the genesis of soils formed from calcareous parent materials and to characterize their properties, as a contribution to the Brazilian Soil Classification System (SiBCS). Three profiles located at footslope (P1), backslope (P2) and summit (P3) positions in a toposequence with slightly undulated relief, were studied in the Serra da Bodoquena, Mato Grosso do Sul […]

The soil structure transformation from ferralic to nitic horizons was studied in a toposequence on quaternary red clayey sediments and diabase in Piracicaba (SP), Brazil. Morphological and micromorphological studies, image analysis, soil water characteristic curves and monitoring of (total) soil water potential head were used. The presence of polyconcave vughs, clayskins and planar voids shows that the vertical and lateral transition and structural transformation from ferralic to nitic horizons is given by the coalescence of the microaggregates, probably due to […]

Soils formed from serpentinized rocks or serpentinites constitute a special group of soils on the earth surface. These rocks present ultramafic characteristics, with more than 70 % mafic minerals (iron and magnesium oxides). The mineralogy of serpentinites is poor in silica and aluminum and very rich in Mg. Only few studies have looked into the morphology, mineralogy, genesis and classification of soils developed on this type of parent material. In the humid-tropical climate of southwestern Minas Gerais state, three representative soil […]

Some of the pedologic alterations resulting from traditional soil management methods were studied in an area cultivated with citrus (Citrus sinensis) in a farm in Bariri County, State of São Paulo, Brazil. A toposequence was established to evaluate the effect of the position in the landscape on changes in soil physical attributes. Field and lab data were taken in vertical profiles of the upper, middle and lower slope levels of a Typic Haplorthox and some parameters were evaluated statistically through […]

A greenhouse experiment was conducted to examine the structural modifications engendered by wetting-drying cycles in Latosol samples (Oxisols) with different mineralogical properties submitted to dry grinding, compared with bulk samples. Air-dried soil samples were sieved through a 1.00 mm sieve and separated in two groups. One was kept as control group and the other ground in a mortar and sieved through a 0.105 mm sieve. This second was also split in two groups, one of which received particulate humic acid […]

A detailed macro- and micromorphological investigation was carried out in two Ultisol (Argissolo Amarelo) and one Aridisol (Planossolo Nátrico) profile from a tableland surface of the San Francisco river basin in Petrolina, Pernambuco State, Northeastern Brazil. The study aimed to characterize the soils micromorphologically, evaluating their pedogenesis to help understand the soil diversity in the landscape. Results indicate that the three soils were developed from Post-Cretaceous sediments mixed with Pre-Cambrian crystalline rock weathered materials and, also, most probably, with materials […]

A soil sequence (Oxisol → Ultisol → Alfisol) was studied on the border of a plateau, which is the oldest regional surface near the Piracicaba river valley (southeastern Brazil). Seven pits were identified, sampled and morphologically described under the different segments of the sequence (end of summit, shoulder, backslope and footslope). A bi-dimensional sketch of the soil horizons was drawn. Undeformed soil samples were taken for micromorphological studies, and mineralogical, chemical and granulometric analyses were performed. The very clayey Oxisols […]

This study aimed to evaluate the relationship between the mineralogical constituents of clay fraction and the development of micro and macrostructure of Latosols (Oxisols) from southeastern Brazil. For that purpose, samples of oxic horizons were obtained from seven Latosols representative of this group, from Minas Gerais and Espírito Santo states. The different soil samples were submitted to morphological, chemical, physical, mineralogical and micromorphological characterizations. From the different results it was possible to conclude that kaolinite and gibbsite are the main […]