Perda de solo em área de nascentes caracterizada por análise multivariada e modelos de geoestatística
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Data
2011-01-19
Autores
Miqueloni, Daniela Popim [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Devido sua importância, a perda de solo das microbacias de cabeceira do Córrego do Tijuco-SP foi estimada por meio da EUPS, e a variabilidade espacial dos fatores do processo erosivo foi investigada pelas análises multivariada e geoestatística. A perda de solo média estimada foi considerada alta, 118,50 Mg ha-1 ano-1, e a correlação de Pearson confirmou o fator erodibilidade do solo como o fator mais importante no processo erosivo. A erodibilidade local é condicionada pela distribuição das frações granulométricas e matéria orgânica, sendo o solo basicamente de textura média/arenosa de baixa coesão. Próxima a zona urbana, a interação do fator erosividade da chuva e do fator práticas conservacionistas se mostrou proeminente evidenciando alta perda de solo devido à concentração de água oriunda da camada impermeabilizada urbana e da falta de controle da velocidade do escoamento superficial da água. Em contraste, o fator cobertura vegetal mostrou maior atuação nas áreas de vegetação permanente, localizadas principalmente nas nascentes e canais de escoamento. Nas áreas mais convexas do terreno, localizadas nos divisores de águas, a atuação do fator erodibilidade foi proeminente, em contraste com o fator topográfico, este em áreas côncavas de maior declividade. Foram observadas ainda áreas com atuação conjunta dos fatores topográfico e erodibilidade, refletindo locais de inclinação mais suave, porém com alto potencial natural de erosão. Os resultados das análises multivariadas e geoestatística permitiram uma estratificação da área estudada identificando locais com propriedades específicas quanto à perda de solo o que contribui na compreensão do processo erosivo para a aplicação das práticas conservacionistas
Because of the importance of headwater watersheds of the Córrego do Tijuco-SP its soil loss was estimated by the USLE and the spatial variability of the erosion process factors was investigated by multivariate analysis and geostatistics. The estimated average soil loss was considered high, 118.50 Mg ha-1ano-1, and Pearson correlation confirmed the soil erodibility factor as the most important factor in the erosion process. Erodibility is conditioned by the local distribution of soil particle-size fractions and organic matter, and soil texture mostly medium/sandy of low cohesion. Near urban areas, the interaction of rainfall erosivity factor and conservation practices factor showed prominent high soil loss due to concentration of water coming from urban soil impermeabilization and the lack of speed control of runoff water. In contrast, the vegetation cover factor showed great performance in the areas of permanent vegetation, mainly located in the headwaters and drainage channels. In areas of more convex topography close to the watershed dividers, the action of erodibility factor was prominent, in contrast to concave areas of greater slope where the topographic factor was more prominent. We also observed areas with joint action of topographic factors and soil erodibility factor, with smoother topography, but with high natural potential of erosion. Results of multivariate and geostatistics analysis enabled to stratify the study area by identifying sites with specific properties of soil loss which helps in understanding the erosion process for the implementation of conservation practices
Because of the importance of headwater watersheds of the Córrego do Tijuco-SP its soil loss was estimated by the USLE and the spatial variability of the erosion process factors was investigated by multivariate analysis and geostatistics. The estimated average soil loss was considered high, 118.50 Mg ha-1ano-1, and Pearson correlation confirmed the soil erodibility factor as the most important factor in the erosion process. Erodibility is conditioned by the local distribution of soil particle-size fractions and organic matter, and soil texture mostly medium/sandy of low cohesion. Near urban areas, the interaction of rainfall erosivity factor and conservation practices factor showed prominent high soil loss due to concentration of water coming from urban soil impermeabilization and the lack of speed control of runoff water. In contrast, the vegetation cover factor showed great performance in the areas of permanent vegetation, mainly located in the headwaters and drainage channels. In areas of more convex topography close to the watershed dividers, the action of erodibility factor was prominent, in contrast to concave areas of greater slope where the topographic factor was more prominent. We also observed areas with joint action of topographic factors and soil erodibility factor, with smoother topography, but with high natural potential of erosion. Results of multivariate and geostatistics analysis enabled to stratify the study area by identifying sites with specific properties of soil loss which helps in understanding the erosion process for the implementation of conservation practices
Descrição
Palavras-chave
Análise espacial (Estatística), Solos - Conservação, Erosão, Spatial Analysis, Soil conservation, Soil erodibility, Erosion
Como citar
MIQUELONI, Daniela Popim. Perda de solo em área de nascentes caracterizada por análise multivariada e modelos de geoestatística. 2011. xii, 88 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2011.