Remediation of oil-contaminated soil by chemical oxidation
01/Nov/2012
The possibilities of remediation of a Latossolo Vermelho Amarelo artificially contaminated with oil (5,000 mg kg-1) were investigated. Different remediation methods with chemical oxidants were compared: KMnO4 0.10 mol L-1; K2S2O8 0.10 mol L-1; H2O2 0.10 mol L-1; H2O2/Fe2+ 0.10/0.08 mol L-1 (Fenton’s reaction) and H2O2/Fe2+/UV 0.10/0.08 mol L 1 (photo-Fenton reaction). The remediation was practically complete (99 %) after 30 min of the photo-Fenton process. No other oxidant reached this dissipation rate after 180 min. The remediation was least […]
Industrial and urban organic wastes increase soil microbial activity and biomass
01/Nov/2012
Microbial processes have been used as indicators of soil quality, due to the high sensitivity to small changes in management to evaluate, e.g., the impact of applying organic residues to the soil. In an experiment in a completely randomized factorial design 6 x 13 + 4, (pot without soil and residue or absolute control) the effect of following organic wastes was evaluated: pulp mill sludge, petrochemical complex sludge, municipal sewage sludge, dairy factory sewage sludge, waste from pulp industry and […]
Soil organic carbon profiles in the South and Southern Espinhaço Mountain Regions, Minas Gerais: modelling of deeper layers
01/Nov/2012
Despite the interest in the spatial variability of key soil properties, depth-related variations have only recently received more attention in the literature. Of all soil properties, soil organic carbon (SOC) is perhaps the most depth-related and difficult to understand. Soil data from two regions in the State of Minas Gerais, Brazil, were used to model SOC profiles and identify factors of influence. In both the South and Southern Espinhaço regions, SOC profiles were best described by log functions. Oxisols had […]
Preconsolidation pressure as a tool for sustainability analysis of soil structure of soil classes under different uses
01/Nov/2012
The main environmental problem caused by land use in permanent protection areas along river banks is the removal of the primary vegetation. Depending on the type and intensity of use, the soil structure of this river banks can be altered and the physical functions modified, especially near the watercourses. The purpose of this study was to evaluate the structural sustainability of three classes of river bank soil using the preconsolidation pressure measurement and thereby assess the impact of these different […]
Carbon balance and crop residue management in dynamic equilibrium under a no-till system in Campos Gerais
01/Nov/2012
The adoption of no-tillage systems (NT) and the maintenance of crop residues on the soil surface result in the long-term increase of carbon (C) in the system, promoting C sequestration and reducing C-CO2 emissions to the atmosphere. The purpose of this study was to evaluate the C sequestration rate and the minimum amount of crop residues required to maintain the dynamic C equilibrium (dC/dt = 0) of two soils (Typic Hapludox) with different textural classes. The experiment was arranged in […]
Nutrition, dry matter accumulation and partitioning and phosphorus use efficiency of potato grown at different phosphorus levels in nutrient solution
01/Nov/2012
High rates of phosphate fertilizers are applied to potato (Solanum tuberosum L.), which may cause antagonistic interactions with other nutrients and limit crop yields when over-supplied. The purpose of this study was to evaluate the influence of phosphorus (P) levels in nutrient solution on P use efficiency, nutritional status and dry matter (DM) accumulation and partitioning of potato plants cv. Ágata. The experiment was carried out in a greenhouse, arranged in a completely randomized block design with four replications. Treatments […]
Sulfur in agriculture
01/Nov/2012
Sulfur (S) deficiency in soils is becoming increasingly common in many areas of the world as a result of agronomic practices, high biomass exportation and reduced S emissions to the atmosphere. In this review, the incidence and commercial exploitation of S pools in nature are discussed, as well as the importance of S for plants and the organic and inorganic S forms in soil and their transformations, especially the process of microbiological oxidation of elemental sulfur (S0) as an alternative […]
Nodulation and nitrogen fixation efficiency of cowpea as affected by inoculum rate
01/Nov/2012
Cowpea (Vigna unguiculata (L.) Walp.) can obtain sufficient N for its own supply from the atmosphere, by the process of biological nitrogen fixation (FBN), when associated with specific and effective rhizobia bacteria. The purpose of this study was to evaluate the effect of different rhizobia inoculum rates on nodulation and biological N fixation by cowpea (cv. BRS Pujante). A complete randomized block design with seven treatments and four replicates was used. The trial was conducted in a greenhouse using 2 […]
Estimating subsoil resistance to nitrate leaching from easily measurable pedological properties
01/Nov/2012
Leaching of nitrate (NO3–) can increase the groundwater concentration of this anion and reduce the agronomical effectiveness of nitrogen fertilizers. The main soil property inversely related to NO3– leaching is the anion exchange capacity (AEC), whose determination is however too time-consuming for being carried out in soil testing laboratories. For this reason, this study evaluated if more easily measurable soil properties could be used to estimate the resistance of subsoils to NO3– leaching. Samples from the subsurface layer (20-40 cm) […]
Carbon and nitrogen stocks in soil under castor bean in the semi-arid Caatinga of Brazil
01/Nov/2012
Much of the Brazilian castor bean (Ricinus communis L.) production is concentrated in the semi-arid region (Caatinga biome) of the Northeast, as an alternative crop. The purpose of this study was to evaluate changes in C and N pools due to land use change in the Caatinga biome by castor bean production. The study was conducted on the Fazenda Floresta in the municipality of Irecê (Mid -North region of Bahia, Brazil). The climate is type BSwh (Koppen) – Semi-arid climate. […]