91 resultados para surface layer
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Pós-graduação em Microbiologia Agropecuária - FCAV
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Pós-graduação em Ciência e Tecnologia de Materiais - FC
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Agronomia (Ciência do Solo) - FCAV
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In crop year 2006/07, in Selviria, MS, Brazil, were analyzed the productivity of beans because of the chemical attributes of an Acrustox cultivated under conditions of high technological level of management by no-tillage irrigated with pivot central. The objective was to select, among the attributes studied soil, the one with the best representation to explain the variability of agricultural productivity. Geostatistical grid was installed to collect data from soil and plant, with 117 sampling points in an area of 2,025 m(2) and homogeneous slope of 0.055 m m(-1). From the standpoint of linear and spatial bean yield was respectively explained in terms of P and soil pH. So much for the values of phosphorus (P) in the intermediate layer and subsurface between 24-26 mg dm(-3), as well as for Hydrogen (pH) in the surface layer between 5.0 to 5.4, resulted in sites with the most high yield (2,160-2,665 kg ha(-1)).
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Agricultural use of tannery sludge (TS) may increase risks to soils. Thus, composting is recognized as one of the most suitable alternatives for TS recycling. Field experiments were carried out to evaluate the effects of composted tannery sludge (CTS) on chromium (Cr), cadmium (Cd), nickel (Ni), and lead (Pb) accumulation in soil after 3 years. Soil samples were collected 60 days after CTS application. After 3 years, The CTS increased Cr and Ni content, while Cd and Pb contents decreased. The third year, Cr contents showed linear increases as CTS rates were applied. The application of CTS, after 3 years, in the 2.5, 5, and 10 Mg ha(-1) increased Cr significantly (140.7%, 159.7%, and 19%, respectively) and Ni (32%, 53%, and 43.8%, respectively) contents in the soil surface layer. This means that consecutive amendments of CTS increase Cr contents in the soil and plants.
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Pós-graduação em Agronomia (Produção Vegetal) - FCAV
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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)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The tropical soil acidity is one of the main limiting factors for crop productivity. This study aimed to evaluate the effects of application of limestone dose to soil fertility, nutritional status of the crop, and productivity and quality of the fruits of mango, cultivar Keitt. The study was carried out at Selviria, state of Mato Grosso Sul, Brazil, in a Typic Haplustox (pH in CaCl2=4.7), cultivated with mango cultivar Keitt grafted on Coquinho pattern in the production phase (13years old). Treatments were composed of limestone doses (0, 1.55, 3.10, 4.65, and 6.20tha(-1)), arranged in blocks at random with three repetitions. The limestone was applied and incorporated in the surface layer of 0 to 5cm deep in the total area. We evaluated the chemical attributes of the soil [pH, hydrogen (H+) aluminum (Al), calcium (Ca), magnesium (Mg), potassium (K), and sum of bases and base saturation] at 16 and 28months after liming (layer 0 to 20cm deep), the nutrition of plants at 12months after liming, and quality of the fruit in two crop years. Liming promoted improvements in soil chemical attributes, reflected in the nutritional status, productivity, and quality of mango fruit. Also, there was a linear effect with the application of lime dose on the productivity of the fruit, but after the second year of evaluation.
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Heavy metals are found naturally in soils at low concentrations, but their content may be increased by human activity, making them one of the barriers in management of tropical soils. These chemical elements can be found in the composition of organic and inorganic fertilizers, insecticides, fungicides, mine tailings, and urban waste, and may cause serious damage to the environment and human health. Thus, adsorption studies are essential in assessing the behavior of heavy metals in the soil. The objective of this study was to evaluate the influence of soil chemical, particle size, and mineralogical properties on adsorption of cadmium (Cd), evaluated by Langmuir and Freundlich models, in Latossolos (Oxisols) with or without human activity. Soil samples were collected from the surface layer, 0.00-0.20 m, and chemical, particle size, and mineralogical analyzes were performed. In the adsorption study, concentrations of 0, 5, 25, 50, 100, 200, 300, and 400 mu g L-1 of Cd were used in the form of Cd(NO3)(2). The empirical mathematical models of Langmuir and Freundlich were used for construction of adsorption isotherms. Data were analyzed by means of multivariate statistical techniques, Cluster Analysis and Principal Component Analysis. The data from the adsorption experiment showed a good fit to the Langmuir and Freundlich models. Soils with a lower goethite/hematite ratio and greater cation exchange capacity and pH, showed higher maximum adsorption capacity of Cd.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)