107 resultados para Universal Soil Loss Equation
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Understanding the linkages between the natural elements is essential for being promoted the land use, occupation and sustainable management of environmental systems. Universal Soil Loss Equation (USLE), as a predictive model of erosion, is important to allowing the prevention of possible environmental impacts which may drastically interfere in natural or anthropic environments, as well as prevent potential financial wastes and even contribute to greater efficiency of agricultural production. This research will be working some USLE parameters, emphasizing topographic factor from Ribeirão Monjolo Grande watershed. Among the factors considered by the USLE, the Topographic Factor interferes directly in the erosive dynamic of a watershed because it involves variables related to hydrological processes that occur on it. In this research, were discussed different methods for obtaining the Topographic Factor (BERTONI e LOMBARDI NETO, 1985; MOORE e BURCH, 1986; DESMET E GOVERS, 1996) in GIS environment. After comparison between the methods, was indicated that best represents the conditions of geometry strand of the study area. Finally, other factors (R, K, C, P) considered by the USLE were obtained. The attainment of these parameters were guided by the use of geotechnologies, especially in Geographic Information Systems (GIS), with the assistance of secondary data and periodic field visits. The results obtained contributed to the understanding of hydrosedimentological dynamic in this area and serve as a viable strategy for studies of soil loss, aiming at developing consistent material for future researches about environmental planning and land management
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Pós-graduação em Agronomia (Ciência do Solo) - FCAV
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This work addresses the erosion caused by rain, describing their steps and factors that most influence the intensity and volume of transported material. The work presents the Universal Soil Loss Equation that quantifies the erosion, with the influence of different factors that affect it. The following notes the occurrence of this process in cutting slopes. They suffer with removal of the vegetation and surface soil layer, making them even more susceptible to this process. In this way it's necessary a protection model for the slopes. Some protection methods are presents with their main features, advantages and disadvantages, implementation process, especially to survey the approximate cost of each method and their application restrictions
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Water erosion is one of the main processes responsible for soil degradation, resulting in loss of parcels of land suitable for agriculture, to the loss of agricultural inputs and the resulting drift of pesticides and excess sediment to rivers, causing phenomena such as the siltation and eutrophication of water bodies. Such a scenario makes it necessary to perform work of a technical and scientific to provide subsidies to land-use planning, in order to protect natural resources biotic and abiotic. To develop this work is necessary to find a unit of analysis capable of integrating the different elements of the landscape, hydrosphere, atmosphere, biosphere and lithosphere. Therefore we adopt for this work the watershed as main unit studies. From this question, this project will focus on the assessment of surface water erosion through MEUPS (Equation Modified Universal Soil Loss) predictive model. With the aid of maps, remote sensing products, and the use of geotechnology, this study aims to evaluate for the for Natural Erosion Potential the basin of the Jacutinga river, located in Rio Claro - SP
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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O objetivo geral foi demonstrar o impacto técnico e econômico das perdas de solo e nutrientes por erosão no cultivo da cana-de-açúcar. Propôs-se avaliar as perdas de nutrientes por erosão (P, K, Ca e Mg), o custo de reposição de nutrientes e o de produção da cana em dois sistemas de colheita (cana crua e queimada) em Catanduva - SP, em área de 100 ha para cada sistema, formadas e colhidas no mesmo período (2002 a 2007), com similaridade quanto ao tipo de solo, variedade, topografia e numero de cortes. A metodologia baseou-se na equação universal da perda de solos e teoria dos custos de produção e de reposição de nutrientes. A maior perda de solo e de nutrientes por erosão ocorreu nas áreas de cana queimada; a cana queimada (corte manual), na média dos cinco cortes, perde 48,82% por hectare a mais de solo, 56,45 % de potássio (K) e 60,78 % de fósforo (P) do que a cana crua (corte mecanizado); o custo de reposição de nutrientes, em média, na cana queimada (R$ 33,92 ha-1 ano-1), foi superior ao da cana crua (R$ 21,12 ha-1 ano-1); a cana crua apresentou menor custo de produção (R$ 29,60 Mg-1) quando comparado à cana queimada (R$ 32,71 Mg-1); a cana crua apresentou maior retorno médio (R$ 5,70 Mg-1ano-1) com relação à cana queimada (R$ 2,59 Mg-1).
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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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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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This study aims at identifying the influence of soil surface roughness from small to large aggregates (random roughness) on runoff and soil loss and to investigate the interaction with soil surface seal formation. Bulk samples of a silty clay loam soil were sieved to four aggregate-size classes of 3 to 12, 12 to 20, 20 to 45, 45 to 100 mm, and packed in soil trays set at a 5% slope. Rainfall simulations using an oscillating nozzle simulator were conducted for 90 min at an average rainfall intensity of 50.2 mm h(-1). Soil surface roughness was measured using an instantaneous profile laser scanner and surface sealing was studied by macroscopic analysis of epoxy impregnated soil samples. The rainfall simulations revealed longer times to initiate runoff with increasing soil surface roughness. For random roughness levels up to 6 mm, a decrease in final runoff rate with increasing roughness was observed. This can be attributed to a decreased breakdown of the larger roughness elements on rougher surfaces, thus keeping infiltration rate high. For a random roughness larger than 6 mm, a greater final runoff rate was observed. This was caused by the creation of a thick depositional seal in the concentrated flow areas, thus lowering the infiltration rates. Analysis of impregnated soil sample blocks confirmed the formation of a structural surface seal on smooth surfaces, whereas thick depositional seals were visible in the depressional areas of rougher surfaces. Therefore, from our observations it can be learned that soil surface roughness as formed by the presence of different aggregate sizes reduces runoff but that its effect diminishes due to aggregate breakdown and the formation of thick depositional seals in the case of rough soil surfaces. Sediment concentration increased with increasing soil surface roughness, due to runoff concentration in flow paths. Nevertheless, final soil loss rates were comparable for all soil roughness categories, indicating that random roughness is only important in influencing runoff rates and the time to initiate runoff, but not in influencing sediment export through soil loss rates.