1000 resultados para Basaltic soils


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This study determined the environmental availability of copper (Cu) in Australian vineyard soils contaminated with fungicide derived Cu residues, and investigated the soil characteristics correlated with differences in Cu availability between regions. Concentrations of 0.01 M calcium chloride extractable Cu, measured in surface soils collected from 98 vineyards in 10 different grape-growing regions of Australia, ranged from <0.1 to 0.94 mg/kg and accounted for 0.10−1.03% of the total Cu concentrations in the soils. Differences in the calcium chloride extractable Cu concentrations were related to the total Cu concentration and soil properties, including pH, clay, exchangeable K, silt, and calcium carbonate. The information generated from this study may prove useful in devising strategies to reduce the availability and toxicity of Cu in agricultural soils.

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Experimentation indicates that water and nutrients move through heterogeneous matrix flow pathways and that nutrients show little variation in concentration with fertilizer application rate after 2 months. However a scatter in concentrations independent of application rates after 4 and 7 months, indicates that external factors are affecting nutrient concentrations within the soil after this time period. Grassmere and Rutherglen were the sample sites.

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In this paper a Neural Network Model was used to develop a ranking of the potential damage influences for light structures on expansive soils in Victoria. These influences include geology, Thornthwaite moisture index, vegetation covers, construction foundation type, construction wall type, geographical region and age of building when first inspected. Approximately 400 cases of damage to light structures in Victoria, Australia were considered in this study. Feedforward Backpropagation was adopted to train the data. The ranking of importance was estimated using connection weight approach and then compared to results calculated from sensitivity analysis. From the analysis, the ranking of importance for potential damage factor was noted.

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Recycled water has facilitated expansion of viticulture in Great Western, Victoria. The recycled water is of medium salinity, and has high concentrations of nutrients and sodium. Irrigation has resulted in increased topsoil EC, pH, and ESP. Laboratory studies identified spatially heterogeneous soils which present a risk of groundwater and offsite contamination.

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Stability charts for soil slopes, first produced in the first half of the twentieth century, continue to be used extensively as design tools, and draw the attention of many investigators. This paper uses finite-element upper and lower bound limit analysis to assess the short-term stability of slopes in which the slopematerial and subgrade foundation material have two distinctly different undrained strengths. The stability charts are proposed, and the exact theoretical solutions are bracketed to within 4.2% or better. In addition, results from the limit-equilibrium method (LEM) have been used for comparison. Differences of up to 20% were found between the numerical limit analysis and LEM solutions. It also shown that the LEM sometimes leads to errors, although it is widely used in practice for slope stability assessments.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)