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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Mapping soil organic carbon storage in deep soil horizons of Amazonian Podzols / Mapeamento do estoque de carbono orgânico em horizontes profundos de Espodossolos da Amazônia

Pereira, Osvaldo José Ribeiro 19 January 2016 (has links)
The Podzols of the world are divided into intra-zonal and zonal according to then location. Zonal Podzols are typical for boreal and taiga zone associated to climate conditions. Intra-zonal podzols are not necessarily limited by climate and are typical for mineral poor substrates. The Intra-zonal Podzols of the Brazilian Amazon cover important surfaces of the upper Amazon basin. Their formation is attributed to perched groundwater associated to organic matter and metals accumulations in reducing/acidic environments. Podzols have a great capacity of storing important amounts of soil organic carbon in deep thick spodic horizons (Bh), in soil depths ranging from 1.5 to 5m. Previous research concerning the soil carbon stock in Amazon soils have not taken into account the deep carbon stock (below 1 m soil depth) of Podzols. Given this, the main goal of this research was to quantify and to map the soil organic carbon stock in the region of Rio Negro basin, considering the carbon stored in the first soil meter as well as the carbon stored in deep soil horizons up to 3m. The amount of soil organic carbon stored in soils of Rio Negro basin was evaluated in different map scales, from local surveys, to the scale of the basin. High spatial and spectral resolution remote sensing images were necessary in order to map the soil types of the studied areas and to estimate the soil carbon stock in local and regional scale. Therefore, a multi-sensor analysis was applied with the aim of generating a series of biophysical attributes that can be indirectly related to lateral variation of soil types. The soil organic carbon stock was also estimated for the area of the Brazilian portion of the Rio Negro basin, based on geostatistical analysis (multiple regression kriging), remote sensing images and legacy data. We observed that Podzols store an average carbon stock of 18 kg C m-2 on the first soil meter. Similar amount was observed in adjacent soils (mainly Ferralsols and Acrisols) with an average carbon stock of 15 kg C m-2. However if we take into account a 3 m soil depth, the amount of carbon stored in Podzols is significantly higher with values ranging from 55 kg C m-2 to 82 kg C m-2, which is higher than the one stored in adjacent soils (18 kg C m-2 to 25 kg C m-2). Given this, the amount of carbon stored in deep soil horizons of Podzols should be considered as an important carbon reservoir, face a scenario of global climate change / Os Espodossolos podem ser divididos em zonais e intrazonais de acordo com área onde ocorrem. Os Espodossolos zonais são típicos de áreas boreais e taiga, delimitados por condições climáticas. Já os intrazonais não são condicionados pelo clima. Os Espodossolo intrazonais brasileiros ocupam uma grande extensão da alta bacia amazônica, tendo sua formação atribuída à ocorrência de lençóis freáticos suspensos associados à acumulação de complexos organometálicos em ambientes ácidos redutores. Esses solos tem a capacidade de estocar grandes quantidades de carbono orgânico em horizontes espódicos profundos (Bh), em profundidades que podem variar de 1,5m a 5m. Pesquisas atuais relacionadas ao estoque de carbono em solos amazônicos, não levam em consideração os estoques encontrados no horizonte Bh (abaixo de 1m de profundidade). Sendo assim, o principal objetivo da presente pesquisa foi quantificar e mapear o estoque de carbono nos solos da bacia do Rio Negro, tendo-se em vista aquele estocado no primeiro metro de solo, bem como o carbono armazenado em até 3m de profundidade. A quantidade de carbono orgânico estocado nos solos da bacia do Rio Negro foi estimada em diferentes escalas de mapeamento, desde mapas locais até a escala da bacia do Rio Negro. Imagens de sensoriamento remoto de alta resolução espacial e espectral foram essenciais para viabilizar o mapeamento dos solos nas áreas estudadas e permitir a estimativa do estoque de carbono. Uma análise multisensor foi adotada buscando-se gerar informações biofísicas indiretamente associadas à variação lateral dos tipos de solo. Após o mapeamento do estoque de carbono em escala regional, partiu-se para a estimativa na escala da bacia do Rio Negro, com base em análise geoestatística (krigagem por regressão linear), imagens de sensoriamento remoto e base de dados de domínio público. Após o mapeamento do estoque de carbono na escala da bacia, constatou-se que os Espodossolos têm um estoque médio de 18 kg C m-2, para 1m de profundidade, valor similar ao observado em solos adjacentes (Latossolos e Argissolos) os quais tem um estoque de 15 kg C m-2. Quando são considerados os estoques profundos, até 3m, a quantidade de carbono dos Espodossolos é superior com valores variando de 55 kg C m-2 a 82 kg C m-2. Estoque relativamente maior que aquele observado em solos adjacentes para esta profundidade (18 kg C m-2 a 25 kg C m-2). Portanto, o estoque de carbono profundo dos Espodossolos, não deve ser negligenciado levando-se em conta cenários futuros de mudanças climáticas
2

Mapping soil organic carbon storage in deep soil horizons of Amazonian Podzols / Mapeamento do estoque de carbono orgânico em horizontes profundos de Espodossolos da Amazônia

Osvaldo José Ribeiro Pereira 19 January 2016 (has links)
The Podzols of the world are divided into intra-zonal and zonal according to then location. Zonal Podzols are typical for boreal and taiga zone associated to climate conditions. Intra-zonal podzols are not necessarily limited by climate and are typical for mineral poor substrates. The Intra-zonal Podzols of the Brazilian Amazon cover important surfaces of the upper Amazon basin. Their formation is attributed to perched groundwater associated to organic matter and metals accumulations in reducing/acidic environments. Podzols have a great capacity of storing important amounts of soil organic carbon in deep thick spodic horizons (Bh), in soil depths ranging from 1.5 to 5m. Previous research concerning the soil carbon stock in Amazon soils have not taken into account the deep carbon stock (below 1 m soil depth) of Podzols. Given this, the main goal of this research was to quantify and to map the soil organic carbon stock in the region of Rio Negro basin, considering the carbon stored in the first soil meter as well as the carbon stored in deep soil horizons up to 3m. The amount of soil organic carbon stored in soils of Rio Negro basin was evaluated in different map scales, from local surveys, to the scale of the basin. High spatial and spectral resolution remote sensing images were necessary in order to map the soil types of the studied areas and to estimate the soil carbon stock in local and regional scale. Therefore, a multi-sensor analysis was applied with the aim of generating a series of biophysical attributes that can be indirectly related to lateral variation of soil types. The soil organic carbon stock was also estimated for the area of the Brazilian portion of the Rio Negro basin, based on geostatistical analysis (multiple regression kriging), remote sensing images and legacy data. We observed that Podzols store an average carbon stock of 18 kg C m-2 on the first soil meter. Similar amount was observed in adjacent soils (mainly Ferralsols and Acrisols) with an average carbon stock of 15 kg C m-2. However if we take into account a 3 m soil depth, the amount of carbon stored in Podzols is significantly higher with values ranging from 55 kg C m-2 to 82 kg C m-2, which is higher than the one stored in adjacent soils (18 kg C m-2 to 25 kg C m-2). Given this, the amount of carbon stored in deep soil horizons of Podzols should be considered as an important carbon reservoir, face a scenario of global climate change / Os Espodossolos podem ser divididos em zonais e intrazonais de acordo com área onde ocorrem. Os Espodossolos zonais são típicos de áreas boreais e taiga, delimitados por condições climáticas. Já os intrazonais não são condicionados pelo clima. Os Espodossolo intrazonais brasileiros ocupam uma grande extensão da alta bacia amazônica, tendo sua formação atribuída à ocorrência de lençóis freáticos suspensos associados à acumulação de complexos organometálicos em ambientes ácidos redutores. Esses solos tem a capacidade de estocar grandes quantidades de carbono orgânico em horizontes espódicos profundos (Bh), em profundidades que podem variar de 1,5m a 5m. Pesquisas atuais relacionadas ao estoque de carbono em solos amazônicos, não levam em consideração os estoques encontrados no horizonte Bh (abaixo de 1m de profundidade). Sendo assim, o principal objetivo da presente pesquisa foi quantificar e mapear o estoque de carbono nos solos da bacia do Rio Negro, tendo-se em vista aquele estocado no primeiro metro de solo, bem como o carbono armazenado em até 3m de profundidade. A quantidade de carbono orgânico estocado nos solos da bacia do Rio Negro foi estimada em diferentes escalas de mapeamento, desde mapas locais até a escala da bacia do Rio Negro. Imagens de sensoriamento remoto de alta resolução espacial e espectral foram essenciais para viabilizar o mapeamento dos solos nas áreas estudadas e permitir a estimativa do estoque de carbono. Uma análise multisensor foi adotada buscando-se gerar informações biofísicas indiretamente associadas à variação lateral dos tipos de solo. Após o mapeamento do estoque de carbono em escala regional, partiu-se para a estimativa na escala da bacia do Rio Negro, com base em análise geoestatística (krigagem por regressão linear), imagens de sensoriamento remoto e base de dados de domínio público. Após o mapeamento do estoque de carbono na escala da bacia, constatou-se que os Espodossolos têm um estoque médio de 18 kg C m-2, para 1m de profundidade, valor similar ao observado em solos adjacentes (Latossolos e Argissolos) os quais tem um estoque de 15 kg C m-2. Quando são considerados os estoques profundos, até 3m, a quantidade de carbono dos Espodossolos é superior com valores variando de 55 kg C m-2 a 82 kg C m-2. Estoque relativamente maior que aquele observado em solos adjacentes para esta profundidade (18 kg C m-2 a 25 kg C m-2). Portanto, o estoque de carbono profundo dos Espodossolos, não deve ser negligenciado levando-se em conta cenários futuros de mudanças climáticas
3

3D advance mapping of soil properties

Veronesi, Fabio January 2012 (has links)
Soil is extremely important for providing food, biomass and raw materials, water and nutrient storage; supporting biodiversity and providing foundations for man-made structures. However, its health is threatened by human activities, which can greatly affect the potential of soils to fulfil their functions and, consequently, result in environmental, economic and social damage. These issues require the characterisation of the impact and spatial extent of the problems. This can be achieved through the creation of detailed and comprehensive soil maps that describe both the spatial and vertical variability of key soil properties. Detailed three-dimensional (3D) digital soil maps can be readily used and embedded into environmental models. Three-dimensional soil mapping is not a new concept. However, only with the recent development of more powerful computers has it become feasible to undertake such data processing. Common techniques to estimate soil properties in the three-dimensional space include geostatistical interpolation, or a combination of depth functions and geostatistics. However, these two methods are both partially flawed. Geostatistical interpolation and kriging in particular, estimate soil properties in unsampled locations using a weighted average of the nearby observations. In order to produce the best possible estimate, this form of interpolation minimises the variance of each weighted average, thus decreasing the standard deviation of the estimates, compared to the soil observations. This appears as a smoothing effect on the data and, as a consequence, kriging interpolation is not reliable when the dataset is not sampled with a sampling designs optimised for geostatistics. Depth function approaches, as they are generally applied in literature, implement a spline regression of the soil profile data that aims to better describe the changes of the soil properties with depth. Subsequently, the spline is resampled at determined depths and, for each of these depths, a bi-dimensional (2D) geostatistical interpolation is performed. Consequently, the 3D soil model is a combination of a series of bi-dimensional slices. This approach can effectively decrease or eliminate any smoothing issues, but the way in which the model is created, by combining several 2D horizontal slices, can potentially lead to erroneous estimations. The fact that the geostatistical interpolation is performed in 2D implies that an unsampled location is estimated only by considering values at the same depth, thus excluding the vertical variability from the mapping, and potentially undermining the accuracy of the method. For these reasons, the literature review identified a clear need for developing, a new method for accurately estimating soil properties in 3D – the target of this research, The method studied in this thesis explores the concept of soil specific depth functions, which are simple mathematical equations, chosen for their ability to describe the general profile pattern of a soil dataset. This way, fitting the depth function to a particular sample becomes a diagnostic tool. If the pattern shown in a particular soil profile is dissimilar to the average pattern described by the depth function, it means that in that region there are localised changes in the soil profiles, and these can be identified from the goodness of fit of the function. This way, areas where soil properties have a homogeneous profile pattern can be easily identified and the depth function can be changed accordingly. The application of this new mapping technique is based on the geostatistical interpolation of the depth function coefficients across the study area. Subsequently, the equation is solved for each interpolated location to create a 3D lattice of soil properties estimations. For this way of mapping, this new methodology was denoted as top-down mapping method. The methodology was assessed through three case studies, where the top-down mapping method was developed, tested, and validated. Three datasets of diverse soil properties and at different spatial extents were selected. The results were validated primarily using cross-validation and, when possible, by comparing the estimates with independently sampled datasets (independent validation). In addition, the results were compared with estimates obtained using established literature methods, such as 3D kriging interpolation and the spline approach, in order to define some basic rule of application. The results indicate that the top-down mapping method can be used in circumstances where the soil profiles present a pattern that can be described by a function with maximum three coefficients. If this condition is met, as it was with key soil properties during the research, the top-down mapping method can be used for obtaining reliable estimates at different spatial extents.
4

Carbono no solo em sistemas integrados de produção agropecuária no Cerrado e na transição Cerrado - Amazônia / Soil carbon under integrated agricultural production systems in the Brazilian savannah (Cerrado) and in the Cerrado-Amazon transition zone

Oliveira, Janaína de Moura 26 June 2015 (has links)
Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2016-04-04T20:27:23Z No. of bitstreams: 2 Tese - Janaína de Moura Oliveira - 2015.pdf: 1868666 bytes, checksum: 5c342df236d2e6fc6f34b5b3a1245073 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-04-05T10:47:36Z (GMT) No. of bitstreams: 2 Tese - Janaína de Moura Oliveira - 2015.pdf: 1868666 bytes, checksum: 5c342df236d2e6fc6f34b5b3a1245073 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-04-05T10:47:36Z (GMT). No. of bitstreams: 2 Tese - Janaína de Moura Oliveira - 2015.pdf: 1868666 bytes, checksum: 5c342df236d2e6fc6f34b5b3a1245073 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-06-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Integrated crop-livestock (iCL) and integrated crop-livestock-forest (iCLF) systems are pointed out as potential soil carbon sinks. However, there are few scientific studies that evaluated the real contribution of these production systems. This work included two studies. The first was to evaluate soil carbon accumulation and its origin in iCLF in the transition zone of the Cerrado-Amazon biomes; the second aimed to calibrate and validate the CQESTR model for the Cerrado ecosystem and to evaluate the effect of soil management practices, including iCL and various scenarios on soil organic carbon (SOC) over time. For the first study two areas under iCLF (iCLF1 and iCLF3, with one and three rows of Eucalyptus urograndis by hedgerow, respectively) were selected. They were cultivated in this system since 2009 in Nova Canaã do Norte, MT. A continuous pasture was used as reference. Soil samples were taken from eight layers (0.0 to 1.0 m) for the evaluation of the bulk density, texture, total C and N and δ¹³C. The second study was conducted in the Cerrado biome. The evaluated areas (Paddock 4 - P4 and Paddock 5 - P5 has been being managed in iCL since 2000. Bulk density and the organic matter content were determined for the 0.0-0.1 and 0.1-0.3 m layers. The CQESTR is a process based model which simulates the effect of climate, crop rotation and tillage management practices on SOC. The model was calibrated with P5 data and validated with P4 data. Its performance was evaluated using statistical regression analysis and the root mean square deviation (MSD). For the first study, the soil C stocks and isotopic composition were affected by the implementation of the iCLF system. The forest component was an important factor for soil C accumulation for both areas under iCLF. The N can be a limiting factor for C accumulation. We concluded that iCLF affected soil C and N stocks in the short term, however, longer iCLF deployment time would be necessary to elucidate the impact of iCLF in the long-term. In the second study model calibration was performed by adjusting the basic decomposition rate coefficient. The measured and simulated values were significantly correlated with an MSD of 2.11, indicating that the model captured spatial-temporal dynamics of SOC in the topsoil. However, CQESTR underestimated SOC for the 0,1-0,3 m layer, probably due to lack of site specific grass or crop root biomass and distribution data under tropical conditions. Additional calibration is required to improve prediction of SOC stabilization process in the subsoil layers of tropical soils. In the long term (20 years), for the superficial (0,0-0,1 m) soil layer, the model simulated C accumulation in iCL and C loss in soybean/corn grain production system independently of the use of zero-tillage or conventional tillage in either of these systems under Cerrado conditions. / Os sistemas de integração lavoura-pecuária (iLP) e integração lavourapecuária- floresta (iLPF) são apontados como potenciais acumuladores de carbono no solo. Entretanto, ainda há poucos estudos científicos que avaliaram a real contribuição desses sistemas de produção. O presente trabalho incluiu dois estudos para avaliação desses sistemas. O primeiro teve por objetivo avaliar a acumulação e a origem do carbono do solo em iLPF na região de transição dos biomas Cerrado-Amazônia; e o segundo estudo teve por objetivo calibrar e validar o modelo CQESTR para o ecossistema Cerrado bem como avaliar o efeito de práticas de manejo do solo, incluindo iLP e vários cenários no carbono orgânico do solo (COS) ao longo do tempo. Para o primeiro estudo foram selecionadas duas áreas sob iLPF (iLPF1 e iLPF3, sistemas com uma linha e três linhas de Eucalyptus urograndis por renque, respectivamente) cultivadas nesse sistema desde 2009 e uma pastagem no município de Nova Canaã do Norte, MT. Amostras de oito camadas (0,0-1,0 m) foram tomadas para avaliação da densidade, textura, teor de C e N total e δ¹³C. O segundo estudo foi conduzido no bioma Cerrado, em área que vem sendo manejada em iLP desde 2000. Foram avaliadas duas áreas, os Piquete 4 (P4) e Piquete 5 (P5). A densidade do solo e o teor de matéria orgânica foram determinados para as camadas 0,0-0,1 e 0,1-0,3 m. O CQESTR é um modelo de simulação de C baseado em processos que simula o efeito do clima, rotações de cultura e práticas de manejo no COS. O modelo foi calibrado com dados do P5 e validado com P4. Seu desempenho foi avaliado usando análise estatística de regressão e o desvio médio quadrático (MSD). No primeiro estudo, a composição isotópica do solo e os estoques de C foram afetados pela implantação do sistema iLPF. O componente florestal foi importante fator na acumulação de C em ambas as áreas sob iLPF. O N pode ser um fator limitante para a acumulação de C. Conclui-se que o iLPF afeta os estoques de C e N do solo no curto prazo, entretanto, novas avaliações com maior tempo de implantação do iLPF poderiam auxiliar na elucidação do comportamento desses elementos no sistema em longo prazo. No segundo estudo, a calibração do modelo foi realizada pelo ajuste do coeficiente da taxa de decomposição básica. Os valores simulados e medidos foram significativamente correlacionados com um MSD de 2,11, indicando que o modelo capturou satisfatoriamente a dinâmica temporal do COS na camada superficial. Entretanto, o CQESTR subestimou o COS para a camada subsequente 0,1-0,3 m, provavelmente devido às diferenças na biomassa e distribuição de raízes de gramíneas de clima tropical e temperado. Calibração adicional é requerida para melhorar a predição do COS e processos de estabilização nas camadas subsuperficiais de solos tropicais. Para a camada 0,0-0,1 m, em longo prazo (20 anos), o modelo simulou acumulação de C em iLP e decréscimo de C em sistema de produção com sucessão soja/milho, tanto sob plantio direto quanto preparo convencional em condições do Cerrado.

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