Volume 26, Number 2, 2002

Groundwater pollution is one of the main factors justifying the study of soil solute movement and the processes of soil solute interaction. A deeper penetration than the expected of the chemicals applied to the soil surface, together with laboratory observations of the decrease of the amount of solutes in the solution passing through the soil, led researchers to consider the soil water (or solution) as having two phases: a mobile phase, θm, and an immobile phase, θim. In this paper, […]

Knowledge on soil shear strength can actually be a very useful tool for the control of slope and gully erosion, as well as for the introduction of mechanical conservation practices in agricultural soils. In order to evaluate the shear strength of five soils in the region of Lavras (MG) and its relation with the weathering rate, an experiment was carried out, using a direct shear machine which allows the collection of undisturbed soil samples. These samples were collected at a […]

The soil water retention curve plays a fundamental role in the development of studies on the dynamics of soil water, modeling of physical soil processes and plant growth. The retention curve is usually obtained by simultaneously measuring water content (θ) and soil water potential (ψ) in a single sample. An alternative procedure is to use several samples per ψ to describe the retention curve. The use of this procedure requires that the variation factors which exist among the samples are […]

Pedotransfer functions are equations used to estimate soil properties of difficult determination, based on other, more easily obtained soil properties. In spite of the considerable number of equations available to predict moisture retention to specific matrix potentials, these should not be used indiscriminatley,since most of them were developed in temperate climate soils, using data obtained by method that differ from the ones used in Brazilian laboratories. The objectives of this study were: (a) to develop pedotransference functions to estimate water […]

Rice cropped under waterlogged conditions may present symptoms of nutritional disorders similar to those caused by iron (Fe) toxicity. The symptoms do not occur in the same intensity in all cultivars and are more frequent in modern cultivars. The aim of our study was to evaluate the plant capacity of oxidizing reduced iron (Fe2+)on the root surface in green house conditions, comparing two rice cultivars (BR IRGA 409 and EPAGRI 108) with different degrees of susceptibility to iron toxicity and […]

The structural features of humic acids (HA) after addition of organic matter from urban residues were evaluated. The HAs were extracted from the surface (0-20 cm) of an ultisol (Seropédica, RJ) and oxisol (Piraí, RJ) which had been treated with the equivalent of 80 t ha-1 (dry material) of compost from urban waste and also sewage sludge. The incubation time in the laboratory was 24 weeks under room temperature and humidity at field capacity. Tha HAs were characterized by elemental […]

When collecting flooded soil solution, it is important to avoid molecular oxygen contact to prevent redox reactions that can modify its chemical composition. This work, carried out in a greenhouse, analyzed the redox status and chemical composition of an Albaqualf, in different depths and duration of flooding, aiming to propose a new methodology to collect flooded soil solution. The study was conducted using 7.0 kg plastic pots, filled with soil material from the surface layer (0-20 cm) in a completely […]

The aim of this study was to verify the influence of mineralogy and former soil use on adsorption and forms of P in Latosols. The following five soils were used to include a wide range of contents of hematite, goethite, kaolinite (Ka) and gibbsite (Gi): (cohesive Yellow Latosol, dystrophic Yellow Latosol, acric Red Latosol, and two dystropherric Red Latosols, one developed from gabbro and one from tuffite), collected from non-cultivated areas and adjacent areas cultivated for long periods, receiving liming […]

Nitrogen accumulation in corn plant is highly influenced by N content in soil and by rate of its absorption by plant in a given growing stage. In order to compare the effects of N application methods on N accumulation and dry matter production by corn plant, an experiment was carried out in the state of Rio Grande do Sul, Brazil, over the 1998/99 growing season. Treatments consisted of two levels of water availability, one adequate to corn crop needs and […]

The present study was conducted to evaluate the nutritional status of sugarcane in Campos dos Goytacazes, Rio de Janeiro, Brazil, by means of sufficiency range and Diagnosis and Recommendation Integrated System (DRIS). Foliar samples were collected in commercial sugarcane fields to evaluate the N, P, K, Ca, Mg, S, Cu, Mn and Zn concentrations. These foliar contents were compared to: (a) sufficiency range described in the literature, (b) average foliar concentration from a high-yielding group cultivated in Campos dos Goytacazes […]