Volume 27, Number 5, 2003

The element Silicon is not deemed essential for plant growth and development, but its absorption can benefit cumulative cultures like rice greatly. The Si content of tropical soils, however, is very low, due to the advanced weathering degree. The objective of this work was to evaluate the growth of rice plants in highlands under plastic tunnels and the effects of nitrogen (N) and Si doses on dry matter production, grain productivity, N content; Si soil and plant contents; and on […]

Pearl millet is usually grown in periods when water is deficient in soil; a fact that possibly affects the K uptake. The experiment in Botucatu, São Paulo State, Brazil, was conducted to evaluate the effects of soil water content (-0.03;-0.05;-0.10 and -0.50 MPa) associated with K rates (15 and 120 mg dm-3 of K) on the K mass flow and diffusion to pearl millet (Pennisetum glaucum (L.) Leek) roots in greenhouse conditions. In pots with soil from the arable layer of a Red […]

Studies into the nutritional efficiency of grafted coffee plants is essential for the selection of graft/rootstock combinations for a maximum development and production. Our objective was the evaluation of the influence of rootstocks on the efficiency of uptake, translocation and use of Ca, Mg, and S in young Coffee arabica L. plants in hydroponic cultivation. The experiment was conducted in a greenhouse and lasted 170 days, using sand as substratum and circulating nutritive solution. Four genotypes of Coffea arabica L. were […]

Increased phosphorus availability in the top soil layer of no-tillage systems can lead to a higher transformation from inorganic into organic phosphorus fractions of different labilities. The preferential phosphorus accumulation forms and fractions under the application of soluble phosphate rates in a no-tillage system were determined. During five and a half years, the following accumulated P2O5 rates: 0, 130, 180, 260, 360, 540, 720, 980, and 1.240 kg ha-1 of P2O5, were applied in the winter and/or summer, whereupon samples of the […]

Soil management has an impact on soil cover and roughness, and, together with other variables, affects water erosion. In São José do Cerrito, State of Santa Catarina, Brazil, three simulated rainfall tests were evaluated during the soybean cycle March 2000 through June 2001 in combination with the five tillage systems: plowing + disking (bare soil) (BS); plowing + disking and soybean crop on dry oat residues (PD); chiseling + disking and soybean crop on dry oat residues (CD); soybean crop […]

The objective of this study was to evaluate physical and chemical soil properties and organic carbon dynamics in a Typic Eutroferric Red Latossol under different land uses (no-till system, irrigated and non- irrigated crops, and native forest) in the savanna region of Santa Helena de Goiás, Goiás State, Brazil. Samples were collected from five soil layers (0.0-0.05, 0.05-0.10, 0.10-0.20, 0.20-0.30, and 0.30-0.40 m) and separated in aggregate size groups of above or below 0.25 mm. Chemical and physical analyses determined the total […]

To design hydraulic structures, a sound estimation of rainfall parameters is necessary, in order to ensure the technical and economical feasibility of the project. Equations to predict intense rainfall are widely used to estimate runoff peak discharge. The difficulty to obtain estimates for sites where no rainfall data are available can be overcome by the interpolation of precipitation data, based on neighboring meteorological stations, through statistical procedures. The objective of this work was to compare the two most accurate statistical […]

This study was undertaken in Campos dos Goytacazes, northern State of Rio de Janeiro, based on soil samples of a vertic Fluventic Eutrochrepts, which had been cultivated with sugarcane for several decades. In one situation, the crop had been cultivated for 55 years without burning the residues at harvesting. On another sugarcane plantation, harvest residues had been burned, and vinasse inputs applied by sprinkle irrigation at a rate of 120 m3 ha-1 yr -1 during 35 years. Soil samples were collected from the soil layers […]

The effects of arbuscular mycorrhizal fungi (AMF) on heavy metal absorption by plants are controversial. This is due to the differences in soil metal availability, AMF and plant species, and also to possible interactions among these and other environmental/abiotic factors. The aim of the experiment was to evaluate the effect of AMF inoculation (Glomus macrocarpum), and soil base saturation (SBS) on growth, nutrition and Pb uptake of soybean grown on a Latossolo Vermelho-Amarelo, an Oxisol. Plots were treated with or […]

Analysis methods and techniques in large numbers which bring forth trustworthy results at low costs have been developed, some of which imply the recycling of diversified materials or the use of natural products. These, opposite to synthetic ones, normally have a low environmental cost. Beeswax fulfills, at least, this last condition. Our study had the aim of characterizing the physical properties of beeswax, and evaluating the possibility of using it as an impermeable covering in the determination of soil bulk […]