In the Lakes Region of Rio de Janeiro State, the occurrence of a drier climate creates a peculiar environment where there is a trend of salinization and presence of xeric vegetation. Physical, chemical, mineralogical and micromorphological properties were studied in selected soil transects. The soils are eutrophic as result of nutrient cycling, low weathering degree, and presence of primary minerals with nutrient reserves in their composition. The occurrence of well developed eutrophic soils (Oxisols) under caatinga (xeromorphic vegetation) on the […]

Behavior differences between soils of the South-American and Velhas geomorphic surfaces of the Cerrado region, all of them under native vegetation cover, were evaluated by physical, chemical, and mineralogical characterizations, and principal component analyses. According to their sub-region and geomorphic surfaces, the soils were separated in three groups: 1. clayey to very clayey texture, low- and mesoferric; 2. medium to sandy texture, lowferric; 3. clayey to very clayey texture, ferric. Water retention in the surface horizons of the studied soils […]

Volumetric soil water content (q) can be evaluated in the field by direct or indirect methods. Among the direct, the gravimetric method is regarded as highly reliable and thus often preferred. Its main disadvantages are that sampling and laboratory procedures are labor intensive, and that the method is destructive, which makes resampling of a same point impossible. Recently, the time domain reflectometry (TDR) technique has become a widely used indirect, non-destructive method to evaluate q. In this study, evaluations of […]

Atrazine, an herbicide of the s-triazine group, was used in laboratory experiments to determine its mineralization and sorption on samples of a Dusky-Red Latosol under conventional and no-tillage systems. Atrazine ring-labeled 14C was added to the soil samples, with the 14CO2 being produced and atrazine-14C soil extracts analyzed by liquid scintillation. The results showed very low mineralization rates of atrazine, which were correlated with the total carbon and nitrogen contents, as well as with soil humic fractions. Atrazine mineralization decreased […]

The purpose of this work was to obtain the retarding factor (R) and the dispersion-diffusion coefficient (D) for chromium (III) in two highly weathered soils collected in São Paulo, Brazil. The influence of the following factors on these two parameters were analyzed: textures, pH and soil organic matter. Samples of the A and B horizons of two soils were used, differing significantly in organic matter contents (a) a Typic Eutrorthox (LVe) and (b) a Typic Haplorthox (LVd). Soil pH of […]

The effects of irrigation and cropping on the properties of soils were studied in the region of the low-medium São Francisco river basin. Six sites were selected, three of them involving Oxisols collected at the Senador Nilo Coelho Project, in Casa Nova, BA, while the remaining three involved Ultisols collected at the Curaçá Irrigation Perimeter in Juazeiro, BA. The selected sites involved non irrigated and irrigated land, different crops and irrigation methods. The soils were morphologically characterized and samples were […]

The agricultural use of soil changes its physical, chemical and biological characteristics. In many instances, these alterations can result in degradation of soil quality, due to destruction of the natural soil cover and excessive use of machines. The objective of this study was to characterize the alterations of some physical and chemical properties of a dystrophic Dark Red Latosol under cerrado vegetation, under different land uses. The soil samples were taken from five different agro-ecosystems: native pasture; improved brachiaria pasture; […]