Research Doctorate - Doctor of Philosophy (PhD) / Amidst growing concerns about global warming, efforts to reduce atmospheric CO2 concentrations (i.e. C sequestration) have received widespread attention. One approach to C sequestration is to increase the amount of C stored in terrestrial ecosystems, through improved land management. Terrestrial ecosystems represent a critical element of the C interchange system, however a lack of understanding of the C cycle at regional and sub-regional scales means that they represent a source of primary uncertainty in the overall C budget. This thesis aims to address this deficiency by developing an understanding of catchment-scale processes critical for accurate quantification of C in the landscape. An investigation into the spatial and temporal dynamics of soil organic carbon (SOC) was conducted for a 150ha temperate grassland catchment in the Upper Hunter Valley, New South Wales, Australia. The major factors controlling the movement, storage, and loss of SOC were investigated, including climate, vegetation cover, soil redistribution processes, topography, land use, and soil type. This study falls into four broad areas. In the first part of this study the spatio-temporal dynamics of soil moisture and temperature at the catchment scale are assessed for a range of soil depths. Data recorded from a network of monitoring sites located throughout the study catchment was compared with independently derived soil moisture and temperature data sets. The data indicates that soil moisture and temperature in surface soil layers were highly dynamic, in their response to rainfall and incoming solar radiation, respectively. Deeper soil layers however were less dynamic, with longer lag times observed with increasing soil depth, as topography, soil type, and landscape position were the dominant controlling factors. Climate related variables are important factors affecting plant growth and net primary productivity. The second part of the study quantified spatial and temporal vegetation patterns using both field-based measurements of above-ground biomass and remotely sensed vegetation indices from the MODIS and Landsat TM 5 platforms. A strong and statistically significant relationship was found between climate variables and MODIS derived NDVI, leading to the development of a predictive vegetation cover model using ground-based soil moisture, soil temperature, and sunshine hours data. The ability of remotely sensed data to capture vegetation spatial patterns was found to be limited, while it was found to be a good predictor of temporal above-ground biomass trends, enabling net primary productivity to be quantified over the three-year study period. In the third part of the thesis soil redistribution patterns and erosion rates were quantified using the caesium-137 method and empirical and physically-based modelling approaches. The impact of soil redistribution processes on SOC distribution was investigated, and the amount of erosion derived SOC loss quantified. A significant proportion of SOC stored within the catchment was found below a soil depth of 0.30m, which is the depth of sampling set out in the IPCC and Australian Greenhouse Office guidelines for carbon accounting. Soil depth was identified as a key factor controlling the spatial distribution of SOC, which is in turn determined by position in the landscape (i.e. topography). The fourth and final part of the study describes how data on erosion derived SOC loss were used in conjunction with net primary productivity estimates, to establish a SOC balance. This involved mapping the spatial distribution of SOC using a high resolution digital elevation model of the catchment, in conjunction with soil depth measurements, and quantifying the total SOC store of the catchment. It was observed that temporal changes in SOC were minimal over the limited three-year study period, however, the continuity of catchment management practices over the previous decades suggest that steady-state conditions have perhaps been reached. The study concludes that the key to increasing the amount of SOC and enhancing carbon sequestration in the soil, is to increase the amount of SOC stored at depth within the soil profile, where factors such as soil moisture and temperature, which control decomposition rates, are less dynamic in space and time, and where SOC concentrations will be less vulnerable to changes occurring at the surface in response to global warming and climate change.

The fate and behaviour of hydrophobic organic compounds (e.g. pesticides) in soils are largely controlled by sorption processes. Recent findings suggest that the chemical properties of soil organic carbon (OC) significantly control the extent of sorption of such compounds in soil systems. However, currently there is no practical tool to integrate the effects of OC chemistry into sorption predictions. Therefore, the K [subscript]oc model, which relies on the soil OC content (foc), is used for predicting soil sorption coefficients (K[subscript]d) of pesticides. The K[subscript]oc model can be expressed as K[subscript]d = K[subscript]oc × foc, where K[subscript]oc is the OC-normalized sorption coefficient for the compound. Hence, there is a need for a prediction tool that can effectively capture the role of both the chemical structural variation of OC as well as foc in the prediction approach. Infrared (IR) spectroscopy offers a potential alternative to the K[subscript]oc approach because IR spectra contain information on the amount and nature of both organic and mineral soil components. The potential of mid-infrared (MIR) spectroscopy for predicting K[subscript]d values of a moderately hydrophobic pesticide, diuron, was investigated. A calibration set of 101 surface soils from South Australia was characterized for reference sorption data (K[subscript]d and K[subscript]oc) and foc as well as IR spectra. Partial least squares (PLS) regression was employed to harness the apparent complexity of IR spectra by reducing the dimensionality of the data. The MIR-PLS model was developed and validated by dividing the initial data set into corresponding calibration and validation sets. The developed model showed promising performance in predicting K[subscript]d values for diuron and proved to be a more efficacious than the K[subscript]oc model. The significant statistical superiority of the MIR-PLS model over the K[subscript]oc model was caused by some calcareous soils which were outliers for the K[subscript]oc model. Apart from these samples, the performance of the two compared models was essentially similar. The existence of carbonate peaks in the MIR-PLS loadings of the MIR based model suggested that carbonate minerals may interfere or affect the sorption. This requires further investigation. Some other concurrent studies suggested excellent quality of prediction of soil properties by NIR spectroscopy when applied to homogenous samples. Next, therefore, the performance of visible near-infrared (VNIR) and MIR spectroscopy was thoroughly compared for predicting both foc and diuron K[subscript]d values in soils. Some eleven calcareous soils were added to the initial calibration set for an attempt to further investigate the effect of carbonate minerals on sorption. MIR spectroscopy was clearly a more accurate predictor of foc and K[subscript]d in soils than VNIR spectroscopy. Close inspection of spectra showed that MIR spectra contain more relevant and straightforward information regarding the chemistry of OC and minerals than VNIR and thus useful in modelling sorption and OC content. Moreover, MIR spectroscopy provided a better (though still not great) estimation of sorption in calcareous soils than either VNIR spectroscopy or the K[subscript]oc model. Separate research is recommended to fully explore the unusual sorption behaviour of diuron in calcareous soils. In the last experiment, two dimensional (2D) nuclear magnetic resonance/infrared heterospectral correlation analyses revealed that MIR spectra contain specific and clear signals related to most of the major NMR-derived carbon types whereas NIR spectra contain only a few broad and overlapped peaks weakly associated with aliphatic carbons. 2D heterospectral correlation analysis facilitated accurate band assignments in the MIR and NIR spectra to the NMR-derived carbon types in isolated SOM. In conclusion, the greatest advantage of the MIR-PLS model is the direct estimation of Kd based on integrated properties of organic and mineral components. In addition, MIR spectroscopy is being used increasingly in predicting various soil properties including foc, and therefore, its simultaneous use for K[subscript]d estimation is a resource-effective and attractive practice. Moreover, it has the advantage of being fast and inexpensive with a high repeatability, and unlike the K[subscript]oc approach, MIR-PLS shows a better potential for extrapolating applications in data-poor regions. Where available, MIR spectroscopy is highly recommended over NIR spectroscopy. 2D correlation spectroscopy showed promising potential for providing rich insight and clarification into the thorough study of soil IR spectra. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1415416 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009

Made available in DSpace on 2014-06-11T19:30:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-06-05Bitstream added on 2014-06-13T20:40:23Z : No. of bitstreams: 1 arroyogarcia_r_dr_botfca.pdf: 1117377 bytes, checksum: 640c0531b51ae26f4c6122ba741bb333 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O manejo inadequado do solo ocasiona a formação de camadas compactadas que prejudicam o desenvolvimento radicular das plantas, diminuindo a disponibilidade de água e nutrientes, enquanto que o acúmulo de carbono pode melhorar a qualidade do solo. Em sistemas com semeadura direta (SSD), com a menor mobilização do solo, pode-se usar, em rotação, plantas com sistema radicular vigoroso, capaz de crescer em condições adversas. Este trabalho teve como objetivo avaliar a ação de espécies de cobertura, gramíneas e uma leguminosa, em rotação com a cultura da soja, nos atributos físicos de um Latossolo, no acúmulo de carbono, nas diferentes frações da matéria orgânica e na produção da soja, em semeadura direta, ao longo de três anos. O experimento foi conduzido em um Latossolo Vermelho distroférrico de textura argilosa, na Fazenda Experimental Lageado, Unesp/Botucatu, nos anos agrícolas de 2006/2007, 2007/2008 e 2008/2009. No outonoinverno foram estabelecidas parcelas com braquiária (Brachiaria ruziziensis), sorgo granífero (Sorghum bicolor) e sorgo consorciado com braquiária. Na primavera, foram cultivados, em subparcelas, milheto (Pennisetum glaucum), cober crop [Sorghum bicolor (L.) Moench x Sorghum sudanense Piper Stapf], crotalária (Crotalaria juncea) ou pousio. A soja foi cultivada como safra de verão. Em março do primeiro ano foram retiradas amostras para caracterização da área experimental. Após o manejo das espécies cultivadas na primavera, no primeiro e terceiro ano, foram retiradas amostras indeformadas nas camadas de 0-5; 7,5-12,5; 15-20; 27,5-32,5 e 47,5-52,5 cm para determinação da densidade do solo, porosidade e curva de retenção de água no solo. Nas mesmas épocas, a estabilidade de agregados foi avaliada em amostras coletadas nas camadas de 0-5 e 5-10 cm. No terceiro ano do experimento, o intervalo hídrico ótimo (IHO) foi determinado... / Compacted layers resulting from inappropriate soil management may impair root growth, thus decreasing water and nutrient acquisition by crops. Conversely, soil quality is improved with soil carbon accumulation. In areas under no-till, crop rotation with plants with vigorous root systems may alleviate soil compaction, as well as increase soil carbon. In this experiment the effects of cover crops on soil physical properties, carbon accumulation, organic matter quality and soybean production under no-till in a compacted soil were studied for three years. The experiment was conducted on a clayey Rhodic Ferralsol, Lageado Experimental Farm, Unesp/Botucatu, in 2006/2007, 2007/2008 and 2008/2009. Congo grass (Brachiaria ruziziensis), grain sorghum (Sorghum bicolor) and a mix of both were cropped during fall-winter. Then, in the spring, pear millet (Pennisetum glaucum), cober crop [Sorghum bicolor (L.) Moench x Sorghum sudanense Piper Stapf] and indian hemp (Crotalaria juncea) were cropped and a treatment under fallow was set on sub-plots. Soybean was cropped as a summer crop. In March of the first year, samples were taken for characterization of the area. Right after spring crops were chemically desiccated in 2006 and 2008, undisturbed soil samples were taken from the layers 0-5; 7.5-12.5; 15-20; 27.5-32.5 and 47.5-52.5 cm to determine bulk density, porosity and water retention curve. At the same time, samples taken from the depths 0-5 and 5-10 cm were used to determine aggregate stability. In the third year, least limiting water range (LLWR) was evaluated in the 7.5-12.5 and 27.5-32.5 cm soil layers. Organic matter characterization was done in the third year, in the depths of 0-5 and 5-10 cm. Roots of spring crops were sampled in the layers 0-5; 5-10; 10-20; 20-40 and 40- 60 cm, one day before chemical desiccation in all growing seasons. Soybean roots were sampled in the same depths at R2 each... (Complete abstract click electronic access below)

Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2017-12-05T12:41:21Z No. of bitstreams: 1 PGCS15MA124.pdf: 1312847 bytes, checksum: 750d88452b24e573464fff88790dbef6 (MD5) / Made available in DSpace on 2017-12-05T12:41:21Z (GMT). No. of bitstreams: 1 PGCS15MA124.pdf: 1312847 bytes, checksum: 750d88452b24e573464fff88790dbef6 (MD5) Previous issue date: 2015-05-15 / The soil organic matter (SOM) is formed by a set of chemical compounds which have different decomposition rates and products of these processes result as the main source of sulfur, phosphorus and nitrogen into the soil. Because of its great importance to the ground, it is of utmost importance to quantify MOS content. Its composition consists of carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P) and sulfur (S), among others, it is difficult to determine its content. Most analytical techniques measure only carbon and estimate the MOS by a conversion factor. The study aimed to develop an analytical method for quantification of soil organic matter by means of a colorimetric method based on image analysis. The proposed method used the carbon oxidation process of Walkley-Black methodology and the resulting solutions were inserted into spectrophotometer cells for a smart phone equipped with a digital camera with a CCD detector (charge coupled device) register the images. These were treated with ImageJ software and the image of each solution has been selected from an area in which 100x100p were extracted RGB intensities (Red, Green and Blue colors, designs, especially for 8-bit data). We analyzed the RGB values and its relations with the MOS concentrations, resulting that the RED channel showed the best relationship with the organic matter content. The data were modeled by a linear regression (ARED = 0.1222 MOS - 0.1621; R² = 0.9934 and p <0.05) and it was possible to build a model that relates the color intensity with concentration. The proposed method showed accuracy of approximately 71% using a standard soil sample (LUFA Speyer - type 2.2), similar to the result obtained with the method currently used (Walkley-Black) which was 74% / A matéria orgânica do solo (MOS) é formada por um conjunto de compostos químicos que possuem diferentes taxas de decomposição, e os produtos desses processos resultam como fontes principais de enxofre, fósforo e nitrogênio para o solo. Devido a sua grande importância para o solo, é de extrema importância a quantificação do teor da MOS. Como a sua composição consiste em carbono (C), hidrogênio (H), oxigênio (O), nitrogênio (N), fósforo (P) e enxofre (S), dentre outros, torna-se difícil a determinação do seu teor. A maioria das técnicas analíticas mensuram apenas carbono e estimam a MOS por um fator de conversão. A pesquisa teve por objetivo o desenvolvimento de uma metodologia analítica para quantificação de matéria orgânica do solo por meio de um método colorimétrico baseado em análise de imagens. O método proposto utilizou o processo de oxidação de carbono da metodologia Walkley-Black e as soluções resultantes foram inseridas em celas espectrofotométricas para que um smartphone equipado com uma câmera digital, com um detector CCD (charge coupled device), registre as imagens. Estas foram tratadas com o software ImageJ e na imagem de cada solução foi selecionado uma área de 100x100p no qual extraíram-se as intensidades RGB (Red, Green e Blue, modelos de cores, especialmente para dados de 8 bits). Analisou-se os valores RGB e suas relações com as concentrações de MOS, resultando que o canal RED apresentou a melhor relação com o teor de matéria orgânica. Os dados foram modelados por meio de uma regressão linear (ARED = 0,1222 MOS – 0,1621; R² = 0,9934 e p < 0,05) e assim foi possível a construção de um modelo que relaciona a intensidade de cor com a concentração. O método prposto apresentou exatidão de aproximadamente 71% usando uma amostra de solo padronizada (LUFA Speyer – tipo 2.2), similar ao resultado obtido com o método usado atualmente (Walkley-Black) que foi de 74%

No Rio Grande do Sul, são escassos os estudos relacionados à identificação e à caracterização de minerais pedogênicos em ampla escala, bem como aqueles que tratam da influência da mineralogia nos aspectos físicos e químicos dos solos. O sistema solo é resultado da combinação de fatores que atuaram ao longo do tempo geológico, fato evidente no estado do Rio Grande do Sul devido a expressiva variabilidade de classes de solos em seu território. Nesse sentido, o estudo objetivou caracterizar a composição mineralógica de solos formados nas diferentes regiões fisiográficas do Rio Grande do Sul e definir combinações físicas, químicas e mineralógicas responsáveis pela adsorção de fósforo nesses solos. Para tal, foram selecionadas 60 amostras representativas de oito classes de solos de pedoambientes oxidados e com distintos graus de intemperização. As amostras foram previamente coletadas sob vegetação natural na camada de 0 a 20 cm de profundidade. Na fração TFSA, foram realizadas análises físicas (granulometria, área superficial específica, suscetibilidade magnética), químicas (carbono orgânico total, teor de óxidos de ferro pedogênicos e óxidos de baixa cristalinidade, teor de fósforo remanescente) e mineralógicas (difratometria de raio x, estimativa dos minerais por área e largura a meia altura). Os dados foram analisados por correlações de Pearson. Os resultados mostraram ampla variação mineralógica devido aos distintos materiais de origem, influenciando a granulometria, ASE e SM. Os valores de COT mostraram relação positiva com os teores de argila e negativa, principalmente, com os teores de Prem, interferindo nos fenômenos de sorção dos solos. Os teores de Fed aumentaram conforme o incremento de argila nos solos e os teores de Feo foram baixos, ambos devido ao avançado estágio de intemperização dos solos. Na fração argila, predomina a caulinita associada a diferentes proporções de argilominerais 2:1 e óxidos de ferro. A adsorção de fósforo apresenta relação expressiva com os teores de argila, de óxidos de ferro, de carbono orgânico total e, consequentemente, com a área superficial específica do solo. / There are few studies in Rio Grande do Sul making relations with the identification and characterization of pedogenic minerals on a large scale, as well as those that establish the influence of mineralogy on physical and chemical aspects of the soil. The soil system is a result of combination of factors that acted over geological time, an evident fact in Rio Grande do Sul state of due to significant variability of soil classes on his territory. Therein, the study intent to characterize the mineralogical composition of soils formed in distinct geographical regions of Rio Grande do Sul and define physical, chemical and mineralogical combinations responsible for phosphorus adsorption in these soils. However, we selected 60 representative samples of eight soil classes of oxidics pedoenvironments and with distinct degrees of mineral weathering. The samples were previously collected under natural vegetation in the 0 to 20 cm deep. In TFSA fraction, were performed physical (soil texture, specific surface area, magnetic susceptibility), chemical (total organic carbon, content of pedogenic (Fed) and low cristalinity (Feo) iron oxides, remaining phosphorus content (Prem)) and mineralogical analyzes (X ray diffraction, estimation per area and width at half height of minerals). Data were analyzed by Pearson correlations. The results showed wide mineralogical variation due to different parent materials, influencing the soil texture, SSA and MS. The TOC values were closely related with the clay fraction and negative relationship, especially with the levels of Prem, interfering in soil sorption phenomena. The Fed contents increased with the clay fraction and Feo contents were low, both due to the advanced soil stage of weathering. The clay fraction had predominantly kaolinite associated with different ratios of 2: 1 clay minerals and iron oxides. The phosphorus adsorption shows a significant relationship with the clay fraction, iron oxides, total organic carbon and, consequently, with the specific surface area of the soil.

Submitted by Lara Oliveira (lara@ufersa.edu.br) on 2017-05-04T21:53:39Z No. of bitstreams: 1 AnaCCSM_DISSERT.pdf: 2417893 bytes, checksum: e4018d4711596aea75785948532dee39 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-05-05T13:56:28Z (GMT) No. of bitstreams: 1 AnaCCSM_DISSERT.pdf: 2417893 bytes, checksum: e4018d4711596aea75785948532dee39 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-05-05T14:59:47Z (GMT) No. of bitstreams: 1 AnaCCSM_DISSERT.pdf: 2417893 bytes, checksum: e4018d4711596aea75785948532dee39 (MD5) / Made available in DSpace on 2017-05-05T14:59:56Z (GMT). No. of bitstreams: 1 AnaCCSM_DISSERT.pdf: 2417893 bytes, checksum: e4018d4711596aea75785948532dee39 (MD5) Previous issue date: 2014-12-15 / When handling the soil and the Savanna perceives its fragility in terms of decomposition of soil organic matter (MOS) and other attributes. The use of appropriate techniques to local agricultural peculiarities conditions taking into account the weather pattern, soil type and management of the Caatinga constitute an essential tool for maintenance of natural resources. With this study we sought a direction about the quantitative fractions of soil organic matter (MOS) and physico-chemical soil for different agricultural use and soil management, aiming to identify which of these were the most sensitive in distinguishing environments , and the Native Forest (AMN) as a reference, identifying which of these showed improvement and / or restrictions in the study sites. The research was conducted at Governador Dix-Sept Rosado, the Settlement Land of Hope Project located in the micro-region of Chapada Apodi-RN, in a Cambisol Eutrophic. The areas studied were: AMN - Native Forest area, AP - area Cajaraneiras orchard, APC - news area with conventional preparation of the soil in intercropping, ACOL - area of colluvium and AAG - Agro-ecological area. Soil fertility analyzes were performed, physical analysis such as resistance to penetration, particle size, bulk density and particle density, as well as total organic carbon analysis and labile and recalcitrant SOM. It was observed that the ground reaction as fertility study areas had neutral to alkaline reactions, without the presence of Al + 3 and Al + H, and no high salinity. The most organic material contribution in AP area (favored increased P, Ca + 2 and K + in the soil, and reduction in Mg + 2 levels and increased resistance to soil penetration, probably due to the trampling of animals. it is concluded that (AAG) retained condition similar to the AMN labile fractions C and recalcitrant organic matter (MOS), even reaching a IMC of 111 and major components shown that the chemical attributes (P, K +, and Ca + 2) and labile and recalcitrant fractions of soil organic matter (MOS) were indicators of separation of environments. However, the most sensitive were labile carbon and carbon management index / Ao manejar os solos da Caatinga percebe-se sua fragilidade em termos de decomposição da matéria orgânica do solo (MOS) e alguns atributos. O uso de técnicas adequadas às condições agrícolas locais, levando em consideração o padrão climático, tipo de solo e o manejo da Caatinga se constituem como ferramenta essencial para manutenção dos recursos naturais. Com este estudo buscou-se um direcionamento a respeito das frações quantitativas da matéria orgânica (MOS) e os atributos físico-químicos do solo em função dos diferentes usos agrícolas e manejo do solo, visando apontar qual destes foram os mais sensíveis na distinção dos ambientes, tendo a Mata Nativa (AMN) como referência, identificando qual destes apresentaram melhorias e/ou restrições nos ambientes estudados. A pesquisa foi desenvolvida no município de Governador Dix- Sept Rosado, no Projeto de Assentamento Terra de Esperança localizado na Microrregião da Chapada do Apodi-RN, em um Cambissolo Háplico eutrofico. As áreas estudadas foram: AMN - área de Mata Nativa, AP - área de Pomar de Cajaraneiras, APC - área coletiva com preparo do solo convencional em cultivos consorciados, ACOL - área de Colúvio e AAG - área Agroecológica. Foram realizadas análises de fertilidade do solo, análises físicas como a resistência a penetração, granulometria, densidade do solo e densidade de partículas, e também análises de carbono orgânico total e frações lábeis e recalcitrantes da MOS. Observou-se que a reação do solo quanto a fertilidade nas áreas estudadas apresentaram reações neutra a alcalina, sem a presença de Al+3 e H+Al, e sem elevada salinidade. O maior aporte de material orgânico na área AP (favoreceu aumento dos teores de P, Ca+2 e K+ no solo, e redução nos teores de Mg+2 e aumento da resistência à penetração do solo, provavelmente, deve-se ao pisoteio dos animais. Conclui-se que a área Agroecológica, manteve condição semelhante à Mata Nativa nas frações de C lábeis e recalcitrantes da matéria orgânica (MOS), atingindo inclusive um IMC de 111. E os componentes principais demonstraram que alguns atributos químicos (P, K+ e Ca+2) e frações lábeis e recalcitrantes da matéria orgânica (MOS) foram indicadores da separação dos ambientes. Todavia, os mais sensíveis foram carbono lábil e índice de Manejo do carbono / 2017-04-27

No Rio Grande do Sul, são escassos os estudos relacionados à identificação e à caracterização de minerais pedogênicos em ampla escala, bem como aqueles que tratam da influência da mineralogia nos aspectos físicos e químicos dos solos. O sistema solo é resultado da combinação de fatores que atuaram ao longo do tempo geológico, fato evidente no estado do Rio Grande do Sul devido a expressiva variabilidade de classes de solos em seu território. Nesse sentido, o estudo objetivou caracterizar a composição mineralógica de solos formados nas diferentes regiões fisiográficas do Rio Grande do Sul e definir combinações físicas, químicas e mineralógicas responsáveis pela adsorção de fósforo nesses solos. Para tal, foram selecionadas 60 amostras representativas de oito classes de solos de pedoambientes oxidados e com distintos graus de intemperização. As amostras foram previamente coletadas sob vegetação natural na camada de 0 a 20 cm de profundidade. Na fração TFSA, foram realizadas análises físicas (granulometria, área superficial específica, suscetibilidade magnética), químicas (carbono orgânico total, teor de óxidos de ferro pedogênicos e óxidos de baixa cristalinidade, teor de fósforo remanescente) e mineralógicas (difratometria de raio x, estimativa dos minerais por área e largura a meia altura). Os dados foram analisados por correlações de Pearson. Os resultados mostraram ampla variação mineralógica devido aos distintos materiais de origem, influenciando a granulometria, ASE e SM. Os valores de COT mostraram relação positiva com os teores de argila e negativa, principalmente, com os teores de Prem, interferindo nos fenômenos de sorção dos solos. Os teores de Fed aumentaram conforme o incremento de argila nos solos e os teores de Feo foram baixos, ambos devido ao avançado estágio de intemperização dos solos. Na fração argila, predomina a caulinita associada a diferentes proporções de argilominerais 2:1 e óxidos de ferro. A adsorção de fósforo apresenta relação expressiva com os teores de argila, de óxidos de ferro, de carbono orgânico total e, consequentemente, com a área superficial específica do solo. / There are few studies in Rio Grande do Sul making relations with the identification and characterization of pedogenic minerals on a large scale, as well as those that establish the influence of mineralogy on physical and chemical aspects of the soil. The soil system is a result of combination of factors that acted over geological time, an evident fact in Rio Grande do Sul state of due to significant variability of soil classes on his territory. Therein, the study intent to characterize the mineralogical composition of soils formed in distinct geographical regions of Rio Grande do Sul and define physical, chemical and mineralogical combinations responsible for phosphorus adsorption in these soils. However, we selected 60 representative samples of eight soil classes of oxidics pedoenvironments and with distinct degrees of mineral weathering. The samples were previously collected under natural vegetation in the 0 to 20 cm deep. In TFSA fraction, were performed physical (soil texture, specific surface area, magnetic susceptibility), chemical (total organic carbon, content of pedogenic (Fed) and low cristalinity (Feo) iron oxides, remaining phosphorus content (Prem)) and mineralogical analyzes (X ray diffraction, estimation per area and width at half height of minerals). Data were analyzed by Pearson correlations. The results showed wide mineralogical variation due to different parent materials, influencing the soil texture, SSA and MS. The TOC values were closely related with the clay fraction and negative relationship, especially with the levels of Prem, interfering in soil sorption phenomena. The Fed contents increased with the clay fraction and Feo contents were low, both due to the advanced soil stage of weathering. The clay fraction had predominantly kaolinite associated with different ratios of 2: 1 clay minerals and iron oxides. The phosphorus adsorption shows a significant relationship with the clay fraction, iron oxides, total organic carbon and, consequently, with the specific surface area of the soil.

Orientadora: Profa. Dra. Lucia Helena Gomes Coelho / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Ciência e Tecnologia Ambiental, 2016. / A poluição dos recursos hídricos é um problema gerado pelo descarte -muitas vezes irregulare inadequado-dos dejetos, efluentes industriais e esgotos domésticos. A matéria orgânica presente neste ambiente pode ser considerada um indicador de poluição ambiental. Para sua determinação e quantificação, utilizam-se indicadoresdiretos e indiretos, sendo um deles o valor de concentração do carbono orgânico total (Corg) presente em umaamostra de água. O nitrogênio, em suas variadas espécies químicas, também é um indicadorque determina a característica de águas residuárias e de corpos hídricos. Em um curso d'água, a determinação química da forma predominante do nitrogênio pode fornecer indicações sobre o estágio da poluição eventualmente ocasionada pelolançamento de esgotos a montante.O nitrogênio Kjeldahl(NNKT) é o indicador nitrogenado característico de uma poluição recente, além de ser a forma dominanteno esgoto domésticobruto. A Região Metropolitana de São Paulo é uma das áreas demaioradensamento urbano do mundo, com consequente comprometimento da qualidade de seus recursos hídricos, sendolocalizada na área da Bacia do Alto Tietê. A Represa Billings é uma das responsáveis pelo abastecimento público de água nessa região. Em vista disso, o objetivo desta pesquisa foio de avaliar a viabilidade do uso da razão molar Corg/NNKTcomo indicadora da qualidade da água na represa Billings, além da sua correlação com o uso do solo.Para tanto, foi feito olevantamento de dados secundários destes parâmetros em cinco pontos amostrais da represa, sendo possível identificar qualitativamente os locais que possuem os maiores impactos antropogênicos ocasionados por despejo de esgoto. Assim como para o sedimento, foi calculada arazão molar Corg/NNKT, e obtiveram-se menoresvalores desta razãopara locais com elevados aportes de matéria orgânica de origem antrópica. Apesar daanálise estatística da razãoCorg/NNKTnão ter apresentado boa correlação com outras variáveis indicadoras de qualidade da água, esta pode ser um indicador qualitativo de interferência antrópica, uma vez que as estações de monitoramento mais impactadaspor aglomerados de moradias no entorno e que não possuem umainfraestrutura adequada, contribuindo assim para a poluição local do meio, são as que apresentaram os menores valores de razão Corg/NNKT, tendoas áreas mais preservadas um valor mais alto dessa relação. / The pollution of water resources is a problem generated by the disposal of waste, industrial effluents and domestic sewage,which are frequently irregular and inappropriate . The organic matter present in the environment isconsidered an indicator of environmental pollution. For its determination and quantification,direct and indirect indicators are used, being one of them the value of the concentration of total organic carbon (Corg) present in a water sample. Nitrogen, in its diverse chemical species, is also an indicator that determines the characteristics of wastewater and water bodies. In a watercourse, the chemical determination of the predominant form of nitrogen can indicate the stage of pollution eventually caused by the dumping of sewage upstream. The Kjeldahl nitrogen (NNKT) is the typical nitrogenous indicator for recent pollution and it is the dominant form in gross domestic sewages. The Metropolitan Area of São Paulois located in the area of the Alto Tiete basin and can be considered one of the greatest urban density in the world, with consequent impairment of the water resources quality,. The Billings Dam is one of the basins responsible for the public water supply in this area. For this reason, the main objective of this research was to evaluate the feasibility of using the molar ratio Corg/NNKTas an indicator of water quality in the Billings Dam, in addition to its correlation withtheland use. The gathering of secondary data of these parameters was made in five sampling points of the dam, where it was possible to qualitatively identify the sites with the largest anthropogenic impacts caused by the sewage disposal. As well as for the sediment, the molar ratio Corg/NNKTwas used andthe lower values of this ratiowere obtainedin sites with high inputs of organic matter from anthropogenic source. Despite the fact that the statistical analysis of Corg/NNKTratios have not shown good correlation with other water quality variables , this value can be used as a qualitative indicator of anthropogenic interference, since the monitoring stations -which are the most affected by surrounding housing clusters and do not have an adequate infrastructure, contributing to local pollution of the environment -werethe ones with the lowest Corg/ NNKTvalues, aswell asthe most preserved areas showed a higher value in this relation.

An important portion of the large northern permafrost soil organic carbon (SOC) pool might be released into the atmosphere as greenhouse gases following permafrost thawing and subsequent SOC decomposition under future warming conditions, resulting in a warming amplification known as the permafrost carbon feedback. Improved knowledge about the amount, composition and distribution of the permafrost SOC pool is essential when assessing the potential magnitude and timing of the permafrost carbon feedback. This study investigates and compares the SOC storage, composition and distribution in two contrasting permafrost environments: a lowland tundra area in NE Siberia (Tiksi study site), and an alpine area in the Russian Altai Mountains (Aktru Valley study site). Soil pedons were sampled down to 1 m depth and analyzed for key soil properties, i.e., DBD, water content, coarse fraction content, %OC, %IC, C/N ratios and δ¹⁵N values. These soil properties are upscaled by vertical subdivisions based on land cover classes. The role of geomorphology in the accumulation and distribution of SOC in the alpine study site is tested by using a landform and a combined land cover-land form upscaling approach. The estimated mean SOC storage in the upper meter of soils in the alpine site is 3.5 ± 0.8 kg C m¯² compared to 21.4 ± 3.2 kg C m¯² in the lowland tundra site (95% confidence intervals). The inclusion of geomorphology in the upscaling in some cases allows identification of SOC hotspots and areas with very low SOC storage within former land cover classes, therefore improving the landscape SOC storage distribution in the area. The much lower SOC stocks in the alpine site of Aktru Valley can be largely explained by the presence of extensive unvegetated areas in high altitudes (60%), the occurrence active layers deeper than the active soil formation, the enhanced SOM decomposition due to coarse grained, well-drained non-frozen soils, and the negligible occurrence of peatlands and buried organics. Instead, the lowland tundra site in NE Siberia presents important amounts of relatively undecomposed SOM in the permafrost layer. Thus, under future climate warming, alpine permafrost environments such as Aktru Valley may become a net C sink due to an upward shift of vegetation zones and an increase in plant productivity and soil development. Contrarily, lowland tundra areas such as Tiksi may become important C sources since the small increase in C uptake by photosynthetic plants will be outweighed by the thawing and subsequent decomposition of the much larger permafrost SOC pool.

The Florida Everglades is a massive and highly managed subtropical wetland ecosystem, strongly influenced by anthropogenic control of freshwater distribution and highly susceptible to a changing climate, including rising sea-level and changes in temperature and rainfall. Shifting hydrologic regimes impact ecosystem function and biogeochemistry, which in turn control the sources, fate, and transport of organic matter. As a master environmental variable, it is essential to understand how organic matter dynamics will respond to changes in the balance between freshwater and saltwater associated with landscape-scale Everglades restoration efforts and climate change. The research comprising this dissertation improves current understanding of the linkages between organic matter and hydrology in the Everglades across a broad range of temporal and spatial scales. A range of research tools, including stable molecular biomarkers, water quality sensors, data synthesis and multivariate statistics were utilized. Biomarkers were used to track particulate organic matter mobilization in response to experimentally manipulated flows and provided initial evidence that sheet flow restoration can re-engineer landscape microtopography, influencing both ecosystem structure and organic matter inputs to Everglades National Park (ENP). Short-term and long-term temporal studies indicated the quantity and quality of dissolved organic carbon responds to changes in freshwater flow to marshes and mangrove forests in ENP, and that spatial patterns and trends are driven by a complex mixture of managed and natural surface water inputs (i.e., rainfall and water management inflows) as well as groundwater discharge. Application of climate scenario forecasting to relationships established between organic matter and hydrologic drivers predicted reductions in dissolved organic carbon export from ENP and changes in organic matter molecular composition. Furthermore, high-frequency measurements showed hydrologic connectivity of freshwater and estuarine organic matter pools at sub-monthly time-scales. In summary, the work presented here clearly indicates strong yet spatiotemporally complex relationships between changes in water and the sources and transport of organic carbon through the Everglades.