Análise dos parâmetros físicos e isotópicos do carbono e nitrogênio no solo como indicadores ambientais para uma microbacia rural em Bauru-SP
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Data
2013-07-31
Autores
Sobral, Anahi Chimini [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Considerando a hipótese de que a mudnças na cobertura da terra gera características do solo que indicam mudanças na performance de execução dos serviços ecossistêmicos normalmente por ele executados e, portanto, na sua qualidade, este trabalho foi desenvolvido com o objetivo de compreender como a alteração da cobertura da terra vem modificando as característica do solo, através da análise de indicadores de qualidade. O trabalho foi conduzido numa microbacia na zona rural do município de Bauru-SP. Foram coletadas amostras de solo a 20 cm de profundidade em 28 pontos selecionados da microbacia, sendo que em dois pontos foram coletadas, além das amostras superficiais, amostras nas profundidades de 20 a 50 cm e de 50 a 80 cm. Adicionalmente, inspecionou-se a ocorrência de diferentes indicadores de erosão, os quais foram selecionados de acordo com levantamento bibliográfico e com as características ambientais locais. As amostras foram previamente tratadas e conduzidas para laboratórios especializados. Em seguida foram realizadas determinaçõs de índices físicos, além do ensaio de granulometria e determinações da assinatura isotópica e dos teores de C e N. A pastagem representa aproximadamente 63% da área total da microbacia. A fração areia foi largamente predominante em todas as amostras. O valor méido do ð13C para pastagens e vegetação remanescente é -21,439% e 24,35%, respectivamente. Esse valor sugere que o material formador da matéria formador da matéria orgânica do solo é predominante de plantas C4, o que pode ser devido à invasão de gramíneas nos remanescentes de vegetação. Em relação ao ð15N, o valor médio para as classes de uso do solo pastagem e vegetação remanescente são, respectivamente, 8,479% e 8,221%. Esse resultado sugere enriquecimento em relação ao N atmosférico nas classes de usos, que pode ser devido...
Considering the hypothesis that land cover change generates soil characteristics tha indicate changes in the ecosystem services execution performance and, therefore, in their quality, the aim of this work was to understand how land cover change has been altering soil characteristics, through quality indicators analysis. The study was conducted in a rural watershed, located in Bauru-Sp. Soil samples were collected ate 20 cm depth in 28 selected points. In two points samples we also collected at 20-50 cm and 50-80 cm depths. The oocurrence of erosion indicators was examined in field, which were selected according to literature and the local environmental characteristics. Samples were previously treated and transported to specialized laboratories. Hence, some physical indices, particle size analysis, isotopic signature and C and N content were determined. Pasture is the main land cover category (63%). Soil is sandy, at every depth, and sand represents 90% of all samples. The ð13C average for pasture and remmant vegetation is -21,439% and 24,359%, respectively. This value suggest taht the material incoporated into the soil organic matter is ingluenced by C4 plants, possibly due to grass invasion into remnant vegetation. In relationto ð15N, average value for pasture and remnant vegetation is, respectively, 8,479% and 8,221%. This result suggests N atmospheric enrichment in land use classes, which may be due to soil N availability, besides indicates the variety of fonts which environment is exploring N. Soil erosion indicators occurred predominantly and more intensively in pastured places. Based on the results, hypothesis is partially confirmed. This conclusion is supported because from the pedological standpoint, accentuated processes that change landscapes tend to accelerate modifications in physical and chemical soil properties and these changes may exceed the tolerable limits and compromising land use capacity
Considering the hypothesis that land cover change generates soil characteristics tha indicate changes in the ecosystem services execution performance and, therefore, in their quality, the aim of this work was to understand how land cover change has been altering soil characteristics, through quality indicators analysis. The study was conducted in a rural watershed, located in Bauru-Sp. Soil samples were collected ate 20 cm depth in 28 selected points. In two points samples we also collected at 20-50 cm and 50-80 cm depths. The oocurrence of erosion indicators was examined in field, which were selected according to literature and the local environmental characteristics. Samples were previously treated and transported to specialized laboratories. Hence, some physical indices, particle size analysis, isotopic signature and C and N content were determined. Pasture is the main land cover category (63%). Soil is sandy, at every depth, and sand represents 90% of all samples. The ð13C average for pasture and remmant vegetation is -21,439% and 24,359%, respectively. This value suggest taht the material incoporated into the soil organic matter is ingluenced by C4 plants, possibly due to grass invasion into remnant vegetation. In relationto ð15N, average value for pasture and remnant vegetation is, respectively, 8,479% and 8,221%. This result suggests N atmospheric enrichment in land use classes, which may be due to soil N availability, besides indicates the variety of fonts which environment is exploring N. Soil erosion indicators occurred predominantly and more intensively in pastured places. Based on the results, hypothesis is partially confirmed. This conclusion is supported because from the pedological standpoint, accentuated processes that change landscapes tend to accelerate modifications in physical and chemical soil properties and these changes may exceed the tolerable limits and compromising land use capacity
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Palavras-chave
Solos - Qualidade, Indicadores, Microbacias Hidrográficas, Isótopos estáveis, Carbono, Nitrogenio, Soils - Quality
Como citar
SOBRAL, Anahi Chimini. Análise dos parâmetros físicos e isotópicos do carbono e nitrogênio no solo como indicadores ambientais para uma microbacia rural em Bauru-SP. 2013. 92 f. Dissertação (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Faculdade de Engenharia, 2013.