Neotropical woodlice (isopoda) colonizing leaf-litter of pioneer plants in a coal residue disposal environment
01/Jun/2011
The irregular disposal of coal combustion residues has adverse impacts on terrestrial ecosystems. Pioneer plants and soil invertebrates play an important role in the recovery of these areas. The goal of this study was to investigate the colonization patterns of terrestrial isopods (Oniscidea) in leaf litter of three spontaneous pioneer plants (grass – Poaceae, shrub – Euphorbiaceae, tree – Anarcadiaceae) at sites used for fly ash or boiler slag disposal. The experiment consisted of eight blocks (four per disposal site) […]
Uptake of manganese in RR soybean under glifosate application
01/Jun/2011
It was hypothesized that Mn uptake efficiency and transport by transgenic, glifosate-resistant soybean would be affected by application of the herbicide. Two experiments were carried out to study manganese uptake, long-distance transport and absorption kinetics of genetically modified soybean as affected by glifosate application. Experiment 1: The treatments consisted of two near-isogenic soybean cultivars grown in nutrient solution (Conquista and Valiosa RR with or without application of glifosate). The Mn levels in the nutrient solution were 0, 0.085, 0.125, 0.250, […]
Fertilization efficiency of potato with farm manure plus fertilizer-N (15N) and residual effect on millet
01/Apr/2011
The N content of the sandy soils in the semi-arid region of Paraíba State cultivated with potato (Solanum tuberosum) is low. Annual applications of farm manure (FM) and mineral N, determined on an empirical basis, have led to accumulation and/or loss of soil nutrients. Thus, the objective of this study was to determine the efficiency of ammonium sulphate (15N) combined with FM applied to potato as well as the residual effects on subsequent millet. A field experiment on an Alfisol […]
Method to estimate soil macroporosity and microporosity based on sand content and bulk density
01/Apr/2011
Macroporosity is often used in the determination of soil compaction. Reduced macroporosity can lead to poor drainage, low root aeration and soil degradation. The aim of this study was to develop and test different models to estimate macro and microporosity efficiently, using multiple regression. Ten soils were selected within a large range of textures: sand (Sa) 0.07-0.84; silt 0.03-0.24; clay 0.13-0.78 kg kg-1 and subjected to three compaction levels (three bulk densities, BD). Two models with similar accuracy were selected, […]
Variation in aggregate-tensile strength as a function of carbon content of two soils in the region of Campos Gerais
01/Apr/2011
Macroscale soil behavior depends on the mechanical properties of individual aggregates. Tensile strength (TS) of soil aggregates has been used as an indicator of management effect on soil quality as related to land use. The objective of this study was to evaluate the change of TS in relation to the variation of soil organic carbon (SOC) content in two soils (Typic Hapludox) with different textures under a long term no-tillage system. The experiment was arranged in a completely randomized 2 […]
Agronomic aspects of leguminous to green fertilization in the Cerrado of the High Jequitinhonha Valley
01/Apr/2011
The intensive and inadequate use of soils accelerates its degradation, requiring the intervention by means of conservation practices to restore the productive capacity of the same. The aim of this study was to evaluate the behavior and development of different legumes used as green manure in soils of the Cerrado, High Jequitinhonha Valley in Turmalina, MG. The experimental design was in randomized blocks with seven treatments and four replications, the treatments were the leguminous: Mucuna nivea, Mucuna aterrima, Dolichos lablab, […]
Data acquisition system for measurement equipment of soil air permeability
01/Apr/2011
The intrinsic permeability or soil air permeability is an important soil property for the identification of changes in soil porous space caused by soil tillage, in estimations of soil properties that are expensive and difficult to be determined in the laboratory, and for the formulation of flux models in cropped and contaminated soils. The purpose of this study was to develop a data acquisition system (electronic module and software) for intrinsic permeability measurement, in laboratory. High precision of the acquisition […]
Soil phosphorus fractions in response to phosphate fertilization in an Oxisol under different land uses
01/Apr/2011
In no-tillage systems there is a tendency of better P use, particularly in areas under longstanding cultivation, but this observation still awaits confirmation. This study had the objective to quantify the inorganic and organic P fractions and evaluate the responses to different P levels in common bean (Phaseolus vulgaris L.) and brachiaria (Brachiaria decumbens) grown in succession, on a Oxisol with distinct previous land use. The experiment was conducted in a greenhouse with samples from the 0-20 cm layer of […]
The costs of soil erosion
01/Apr/2011
The aim of this study was a survey of the estimated costs of soil erosion, an issue of fundamental importance in view of the current worldwide discussions on sustainability. A list was drawn up of research papers on erosion (on-site and off-site effects) and their respective costs. The estimates indicate the amount of resources spent in the process of soil degradation, raising a general awareness of the need for soil conservation. On-site costs affect the production units directly, while off-site […]
Humic substances and their interactions with Fe and Al in a subtropical oxisol under different pasture management systems
01/Apr/2011
Pasture management systems are, in general, based on the grazing intensity and pressure, dry forage cutting, soil fertility improvement or vegetation burning. In view of the influence of soil management systems on soil organic matter (SOM) dynamics, this study aimed to evaluate soil carbon and nitrogen distribution, and to investigate humic substances (HS) and their interactions with Fe and Al ions in a subtropical Oxisol in the following environments: native pasture without burning for the last 41 years, native pasture […]