Volume 25, Number 1, 2001

High acidity predominates in southeastern and midwestern Brazilian soils, where the largest area of sugar cane plantations is concentrated. Large amounts of slag, a steel-industry residue containing nutrients such as calcium and magnesium and acting as acidity corrective agents, are also present in the region. This study aimed to evaluate different base saturation levels using slag as a soil corrective agent. This material was compared to calcitic limestone to analyze acidity neutralization and certain chemical soil properties, as well as […]

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 effectiveness of the nitrogen supplying to bean plants as fertilizer and, or, as biological nitrogen fixation, and the dependence of these processes on molibdenum availability is still a not well solved problem. The objective of this study was to evaluate the effect of foliar application of Mo on nitrogenase and nitrate reductase activities and on productivity of beans cultivated on a Red Yellow Podzolic, in Coimbra, MG (Brazil). The treatments consisted of increasing rates of foliar application of Mo […]

Mixed plantations of eucalypt and acacia can be beneficial from both the ecological and economic viewpoints, as they increase the biological diversity and reduce the costs of nitrogen fertilization. This trial had the objective to evaluate the effect of mixed plantations of Eucalyptus saligna (Smith) and Acacia mearnsii (De Wild) on soil and stand characteristics. The experiment was carried out on a Red Yellow Latosol, in the state of Rio Grande do Sul, Brazil, and the treatment consisted of pure […]

The understanding of the physics of root aeration may allow a more correct and dynamic estimate of the minimum air-filled porosity, providing a more complete estimate of the plant behavior in relation to soil water content and gas conductivity of the soil. The aeration process is physically described in this paper to show that the result may be useful for estimating minimum air-filled porosity as a function of the total soil porosity, depth to be aerated and oxygen consumption rate. […]

The term “cohesive” has been used in Brazil to distinguish sub-surface soil horizons that have hard, very hard or extremely hard consistency when the soil is dry, and friable when the soil is wet. Australian soils with similar behavior were identified as hardsetting. Researchers have indicated that many soils in Africa and other semi-arid regions can also be characterized as hardsetting. Based on the definition and characteristics of the hardsetting soils, it is believed that “cohesive” soils of the Low […]