Although the influence of clay mineralogy on soil physical properties has been widely studied, spatial relationships between these features in Alfisols have rarely been examined. The purpose of this work was to relate the clay minerals and physical properties of an Alfisol of sandstone origin in two slope curvatures. The crystallographic properties such as mean crystallite size (MCS) and width at half height (WHH) of hematite, goethite, kaolinite and gibbsite; contents of hematite and goethite; aluminium substitution (AS) and specific […]

Pastures are the fodder supply of Brazilian livestock, and are exhaustively degraded by nitrogen (N) deficiency. Intercropping with legumes, aside from nitrogen fixation, may have secondary effects on soil fertility, such as acidification or nutrient movement from deeper to the surface soil layers. This study evaluated the soil litter stock and fertility of degraded Brachiaria decumbens pastures after planting leguminous shrubs and forage trees. For this purpose, we sampled (March 2010) degraded Brachiaria decumbens pasture planted in July 2008 in […]

Pedotransfer functions (PTF) were developed to estimate the parameters (α, n, θr and θs) of the van Genuchten model (1980) to describe soil water retention curves. The data came from various sources, mainly from studies conducted by universities in Northeast Brazil, by the Brazilian Agricultural Research Corporation (Embrapa) and by a corporation for the development of the São Francisco and Parnaíba river basins (Codevasf), totaling 786 retention curves, which were divided into two data sets: 85 % for the development […]

A good knowledge of the spatial distribution of clay minerals in the landscape facilitates the understanding of the influence of relief on the content and crystallographic attributes of soil minerals such as goethite, hematite, kaolinite and gibbsite. This study aimed at describing the relationships between the mineral properties of the clay fraction and landscape shapes by determining the mineral properties of goethite, hematite, kaolinite and gibbsite, and assessing their dependence and spatial variability, in two slope curvatures. To this end, […]

Phosphorus (P) applications to vineyards can cause P accumulation in the soil and maximize pollution risks. This study was carried out to quantify the accumulation of P fractions in sandy soils of vineyards in southern Brazil. Soil samples (layers 0-5, 6-10 and 11-20 cm) were collected from a native grassland area and two vineyards, after 14 years (vineyard 1) and 30 years (vineyard 2) of cultivation, in Santana do Livramento, southern Brazil, and subjected to chemical fractionation of P. Phosphorus […]

The use of audiovisual resources in soil teaching, as a stimulus for students, can be useful to develop students’ critical and reflexive knowledge. This study aimed to analyze the contribution of the video “Conhecendo o Solo” (“Knowing the Soil”) in teaching and learning about this subject in elementary school. In order to stimulate students to realize the importance of soils in the environment, the video was used as teaching content. Then, some questions were applied in which the students described […]

The floodplains of the Solimões River are areas periodically flooded with predominance of Gleisols,where have lived a large number of small farmers of the region. The purpose of this study was to characterize and classify five profiles of Gleysoils distributed in three floodplain areas of the Middle Amazon basin, located in the municipalities of Manacapuru and Iranduba. After the morphological description, the soil horizons were sampled to perform physical, chemical and mineralogical analyses. Similarly, significant gleization was observed in all […]

The use of SMP pH to estimate the potential acidity (H + Al) is more practical than the method of 0.5 mol L-1 calcium acetate for routine laboratory analyses. The objective was to fit an equation to estimate the H + Al from SMP pH values of soils of the State of Pará. From various regions of the state, 177 soil samples were collected, in which the SMP pH was determined in 0.01 mol L-1 CaCl2 solution and H + […]

Soil infiltration is a key link of the natural water cycle process. Studies on soil permeability are conducive for water resources assessment and estimation, runoff regulation and management, soil erosion modeling, nonpoint and point source pollution of farmland, among other aspects. The unequal influence of rainfall duration, rainfall intensity, antecedent soil moisture, vegetation cover, vegetation type, and slope gradient on soil cumulative infiltration was studied under simulated rainfall and different underlying surfaces. We established a six factor-model of soil cumulative […]

The conversion of natural areas for agricultural use can degrade the soil structure and increase the occurrence of compression. This study aimed to evaluate changes in the physico-mechanical and hydro-physical properties of an Endoaqualf, caused by the conversion of a natural area into a rice field. Hydro-physical (density, porosity, macroporosity, microporosity, void ratio, and water retention) and mechanical properties (preconsolidation pressure, compression index, coefficient of decompression, and recovery rate) were evaluated in the horizons A1 (0.0-0.25 m), A2 (0.25-0.51 m), […]