Characterization of soil structure and porosity under long-term conventional tillage and no-tillage systems
01/Dec/2009
Different management systems tend to modify soil structure and porosity over the years. The aim of this study was to study modifications in the morphostructure and porosity of dystroferric Red Latosol (Oxisol) under conventional tillage and no-tillage over a 31- year period. The study began with the description of soil profiles based on the cropping profile method, to identify the most compact structures, define sample collection points for physical and chemical analysis, and determine the water retention curve. A forest […]
CO2, CH4 and N2O fluxes in an Ultisol treated with sewage sludge and cultivated with castor bean
01/Dec/2009
Organic residue application into soil alter the emission of gases to atmosphere and CO2, CH4, N2O may contribute to increase the greenhouse effect. This experiment was carried out in a restoration area on a dystrophic Ultisol (PVAd) to quantify greenhouse gas (GHG) emissions from soil under castor bean cultivation, treated with sewage sludge (SS) or mineral fertilizer. The following treatments were tested: control without N; FertMin = mineral fertilizer; SS5 = 5 t ha-1 SS (37.5 kg ha-1 N); SS10 […]
Molecular weight distribution of humic acids and root growth promotion
01/Dec/2009
Humic acids (HA) directly stimulate several physiological processes that promote plant growth, particularly of the root system. Knowledge about the chemical nature and the role of HA in the effects observed under biofertilization and biostimulation is essential to develop HA-based biological resources. The aim of this study was to evaluate a possible relationship between the distribution of the apparent molecular weight of HA isolated from vermicompost and the response in root growth promotion. HA sub-fractions were obtained through preparative chromatography […]
Application of lime with different reaction degrees: chemical changes in soil under corn
01/Dec/2009
With acidity correction, important nutrients for the corn development become more available to the plants, increasing yield. The objective of this study was to evaluate chemical changes in two soils and corn dry matter yield as affected by lime application with different degrees of reaction. The experiment was carried out in a greenhouse on a Oxisol and a Quartzpsament. Three rates of three commercial limes were applied, one with mean reactivity A (RE = 85.7 %; PRNT = 88.3 %), […]
Heavy metals in soils of a lead mining and metallurgy area. I – Phytoextraction
01/Dec/2009
Phytoextraction has been suggested as a viable alternative to traditional restoration practices for heavy metal-contaminated soils (e.g., soil removal and disposal in land fill areas, or co-processing in cement), in view of the lower costs and lower environmental impact. This study had the objective of evaluating induced phytoextraction (use of chelating agent) of heavy metals in black oat (Avena strigosa Schreber), sunflower (Helianthus annuus L.) and Bahiagrass (Paspalum notatum Flügge) in polluted soils (soils 2, 3, and 4) of a […]
Irrigation water quality influence on clay dispersive behavior of Oxisols
01/Dec/2009
The phenomenon of dispersion of soil clay can be caused by the quality of irrigation water. This study investigated the effect of irrigation water with different electric conductivities (EC), combined with different Sodium Adsorption Relation (SAR) values on clay dispersion in soil commonly found in the state of Minas Gerais, with different mineralogies. The samples were collected from the B horizon of three soils (Oxisols) in Viçosa, Belo Horizonte and Barroso, respectively, with high levels of the clay minerals kaolinite, […]
Simulated soil carbon and nitrogen dynamics in an Acrisol of Rio Grande do Sul State using the Century model
01/Dec/2009
Several studies have shown the satisfactory performance of the Century Model to study soil organic matter (SOM) for the climatic and edaphic conditions of Rio Grande do Sul. However, soil N stocks were usually overestimated in these simulations. The objective of this study was to parameterize the N cycle submodel of Century for a successful use in N dynamic studies in Southern Brazil. For the simulations, data from a long-term study site established in an Acrisol (Argissolo Vermelho distrófico) at […]
Soil macrofauna in three succession stages of a seasonal semidecidous forest and a mixed pasture in Pinheiral – Rio de Janeiro State
01/Dec/2009
Among a number of organisms that constitute soil macrofauna communities, distributed in different types of habitats, with varied foraging habits and life cycles, some are capable of a rapid response to environmental changes. These organisms are considered efficient indicators of the well-functioning of ecosystems. The main objective of this study was to evaluate the effects of the following succession stages of a seasonal semidecidous submontane forest of the Atlantic Forest domain: Secondary Forest Initial Stage – SFIS, Medium Stage – […]
Copper phytoavailability and corn dry biomass production after swine manure application
01/Dec/2009
The residues of swine production have a great potential as soil chemical conditioners for crop production The purpose of this study was to evaluate: (a) corn yield, after application of swine manure and increasing doses of soluble copper in an Eutroferric Red Latosol with two organic matter contents (34,09 and 8,60 g dm-3), (b) the influence of soil copper and organic matter content on copper absorption and translocation to corn shoots. The study was set up in a greenhouse of […]
Carbon content in Amazonian Oxisols after forest conversion to pasture
01/Dec/2009
Soil plays an important role in the C cycle, and substitution of tropical forest by cultivated land affects C dynamic and stock. This study was developed in an area of expansion of human settlement in the Eastern Amazon, in Itupiranga, State of Pará, to evaluate the effects of native forest conversion to Brachiaria brizantha pasture on C contents of a dystrophic Oxisol. Soil samples were collected in areas of native forest (NF), of 8 to 10 year old secondary forest […]
