Volume 34, Number 4, 2010

Crop-livestock integration can affect soil physical properties, altering the yield and plant composition during the various no-tillage crop cycles. The objective of this study was to select the soil properties with the clearest relationship with yield and crude protein content of Brachiaria brizantha. Linear and spatial correlations were analyzed between dry matter yield and crude protein of Brachiaria brizantha and of some physical properties of a Dystroferric Red Latosol (Oxisol), in three layers (0-0.10; 0.10-0.20; 0.20-0.30 m). A geostatistical grid was […]

Evaluating plant root capacity in extrating water from the soil is important for transpiration modeling and to understand crop growth and yield and soil water and nutrient balance. Aiming to test a macroscopic root water extraction model based on the microscopic process description, an experiment was described in which the root system of plants penetrated different soil layers with contrasting hydraulic properties. Four lysimeters containing two physically divided compartments were built and filled with material of two soils with different […]

A very active and influential parameter in the erosive process is the R factor, called rainfall erosivity. This factor is one of the components of the universal soil loss equation. Studies in spatial variability have been conducted in an attempt to define the spatial distribution of the R factor for a given region. This study aimed to calculate the rainfall erosivity (R factor – EI30) to generate spatial maps. The study was conducted in experimental areas of eucalyptus stands in […]

The contribution of humic substances of different composts to the synthesis of humin in a tropical soil was evaluated. Increasing doses (0, 13, 26, 52, and 104 Mg ha-1) of five different composts consisting of agroinpowderrial residues were applied to a Red-Yellow Latosol. These composts were chemically characterized and 13C NMR determined and the quantity of the functional alkyl groups of humic acids applied to the soil as compost was estimated. Thirty days after application of the treatments, organic matter samples were […]

In the State of Rio Grande do Sul, Brazil, flooded rice fields using Patos Lagoon as the source of water for irrigation are subject to be damaged by salinity, since this source is bound to the sea on its southern end. The sensitivity of rice is variable during plant development, being higher in the seedling and reproductive periods. However, there is not enough information about the behavior of plants under salt stress during the course of its development, especially in […]

Phosphorus is among the macronutrients the least absorbed by plants. Nevertheless, the amount of P-containing fertilizers applied to humid tropical and subtropical soils in relatively high. The reason is the strong interaction between of P and Fe and Al oxides, which are abundant in these soils. The study of these interactions is fundamental to know more about the relations between phosphorus adsorption and soil constituents. The objective of this study was to evaluate how the minerals in the clay fraction, […]

Eucalypt is the main commercial forest species in Brazil, but very little information is available in the literature on the amount of carbon stored in the soil and in the biomass of these forest stands. The main objective of this study was to estimate the amount of soil-stored carbon (SSC) of eucalypt plantations and determine soil and climate characteristics that influence SSC. The study was carried out in the Central-Eastern region of Minas Gerais State, Brazil, in five micro-regions (CO, […]

In spite of modern and sophisticated techniques, procedures of selective dissolution are still of considerable value for soil characterization and to the understanding of the pedogenetic process, especially environments and soils poorly studied, as the coastal plain regions and Spodosols of Brazil. The application of these techniques commonly used for characterization of spodic horizons and soil profiles for large amount horizons and soils studied in cronossequences are rare for those environments and become possible to establish comparisons with those intensively […]

Seeds with a high concentration of P or Mo can improve the growth and N accumulation of the common bean (Phaseolus vulgaris L.), but the effect of enriched seeds on biological N2 fixation has not been established yet. This study aimed to evaluate the effect of seeds enriched with P and Mo on growth and biological N2 fixation of the common bean by the 15N isotope dilution technique. An experiment was carried out in pots in a 2 x 3 x 2 x 2 factorial design […]

Soybean is a major grain crop in Brazil, and yields can be considerably improved by inoculation with selected Bradyrhizobium strains. However, the incompatibility between inoculation and seed treatments with fungicides and micronutrients represents a major barrier to the achievement of high rates of biological N2 fixation. Inoculation practices that can alleviate the negative effects of agrochemicals must therefore be found and in-furrow inoculation seems to be an attractive alternative. This study reports the results of seven field experiments conducted in […]