A ciclagem do nitrogênio (N) apresenta dinâmica complexa, pelas múltiplas transformações e por sua mobilidade no sistema solo-planta-atmosfera. Assim, o estudo das taxas de conversão do ciclo interno de N é fundamental, visto que essas taxas têm efeito direto na produtividade e na qualidade ambiental de um agroecossistema. O objetivo deste trabalho foi avaliar o efeito da temperatura e umidade na taxa de mineralização bruta de N (TMB) em solos cultivados com canade- açúcar no estado de São Paulo, e por meio de modelo matemático, estimar a TMB considerando as variações de temperatura e umidade do solo in situ. Foram utilizados um LATOSSOLO VERMELHO distrófico (LVd) e um LATOSSOLO VERMELHO eutrófico (LVe), coletados nos municípios de Piracicaba e Santa Cruz das Palmeiras, respectivamente. As amostragens foram realizadas nas camadas de 0-10, 10-20 e 20-30 cm do solo, em julho de 2010. A quantificação da TMB em laboratório foi realizada por meio de incubações nas temperaturas de 15, 20, 25 e 30 °C, além de quatro umidades (30, 40, 60 e 80 % da capacidade máxima de retenção de água - CMRA). Foi utilizada a técnica da diluição do isótopo 15N, com aplicação de solução de (15NH4)2SO4 nas amostras de solo e determinação do teor de N-NH4 + e da abundância isotópica 48 e 96 h após a marcação. A simulação da mineralização bruta em condições de campo foi efetuada por meio das isotermas da TMB juntamente com dados de umidade e temperatura do solo dos dois ensaios. O período modelado ocorreu entre as fases de adubação e colheita da soqueira. O conteúdo de N-NH4 + do solo apresentou valores reduzidos nas diferentes temperaturas, independentemente da camada, umidade e tipo de solo. As TMB foram relativamente baixas (menores que 2,5 mg kg-1 dia-1 de N) para todos os tratamentos. Em geral, a taxa de consumo bruto (TCB) foi maior que a TMB, indicando alta imobilização/nitrificação. Foi verificado estímulo na TMB com o aumento da umidade e temperatura, para ambos os solos. A TMB e TCB foram maiores na temperatura de 25 °C e a 60 % da CMRA. A modelagem matemática indicou maior TMB entre os meses de novembro a março, marcada pelas chuvas intensas e temperaturas elevadas. O acúmulo de N-NH4 + amonificado durante os meses simulados alcançou 133 e 91 kg ha-1 para os solos LVe e LVd respectivamente.. A metodologia de diluição do isótopo 15N é uma potencial ferramenta para quantificar a mineralização de N / The N cycling has a complex dynamics, due to the multiple transformations and its mobility in the soil-plant-atmosphere. Thus, the study of the conversion rates of the N internal cycle is crucial because these rates have direct effect on yield and environmental quality of an agroecosystem. The aim of this study was to evaluate the effect of temperature and humidity on gross N mineralization (GNM) in sugarcane cropped soils in São Paulo state, and through mathematical model estimates the GNM considering the variations of soil temperature and humidity in situ. Was used a Typic Hapludox (TH) and a Typic Eutrustox (TE), sampled in the cities of Piracicaba and Santa Cruz das Palmeiras respectively. Samples were taken at 0-10, 10-20 and 20-30 cm soil, in July 2010. Quantification of GNM in the laboratory was performed by incubation at 15, 20, 25 and 30 °C, and four humidities (30, 40, 60 and 80 % of the water holding capacity - WHC). Was used the 15N isotope dilution technique, with application of (15NH4)2SO4 solution in the soil samples and subsequent determination of N-NH4 + and isotopic abundance after 48 and 96 h of labeling. The simulation of gross mineralization under field conditions was performed through the GNM isotherms and the data from soil moisture and temperature of the two sites. The modeled period was between the N fertilization and sugarcane harvesting phases. The N-NH4 + soil content showed reduced values at different temperatures, regardless of layer, moisture and soil type. The GNM were relatively low (less than 2.5 mg kg-1 day-1 of N) for all treatments. In general, the gross consumption (GC) was higher than the GNM, indicating high immobilization/nitrification. Stimulation was observed in GNM with increasing humidity and temperature, in both soils. The GNM and GC were higher at 25 °C and 60 % of WHC. Mathematical modeling indicated higher GNM between the months November to March, marked by heavy rains and high temperatures. The accumulation of mineralized N-NH4 + in the model achieved 133 and 91 kg ha-1 for soils and LVe LVd respectively. The 15N isotope dilution method is a potential tool to quantify the N mineralization.

Orientador: Jacinta Enzweiler / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-17T09:52:02Z (GMT). No. of bitstreams: 1 Cotta_AloisioJoseBueno_D.pdf: 12674950 bytes, checksum: 5c83c715500dcc83803f8d9b7d8712f1 (MD5) Previous issue date: 2010 / Resumo: A espectrometria de massas com plasma indutivamente acoplado (ICP-MS) possibilita determinações multielementares rápidas e com baixos limites de detecção numa variedade de matrizes, dentre elas as geológicas. Neste estudo, métodos comparativos utilizando um ICP-MS quadrupolar equipado com cela de colisão (CC) foram estabelecidos para determinar amplos conjuntos de elementos-traços em águas e em rochas. A aplicabilidade e as limitações da CC para atenuar interferências poliatômicas sobre os isótopos empregados foram amplamente investigadas. Em condições ótimas, muitas interferências puderam ser eliminadas ou significativamente atenuadas, o que tornou os métodos menos dependentes de correções matemáticas. Para a análise de rochas, técnicas clássicas de dissolução envolvendo misturas ácidas, como HF/HNO3, foram utilizadas e um novo procedimento com equipamento que possibilita efetuar a digestão sob pressão de até 13 MPa é proposto. Nesse caso, a precipitação de AlF3, o qual retém alguns elementos-traço, principalmente Co, Sr, Ba e Pb, foi o maior obstáculo à recuperação quantitativa dos analitos. A formação de AlF3 foi evitada com a adição de Mg à porção teste e com o controle da temperatura de digestão. A decomposição por sinterização com peróxido de sódio foi também investigada e verificou-se que a inclusão de uma etapa de aquecimento da dispersão resultante da dissolução do sinterizado em água, antes da separação do precipitado de hidróxidos de Fe e Ti, o qual retém os elementos-traço, auxilia na coprecipitação de Ni, Zr, Nb, Cd, Sn, Sb, Hf, Pb e Th e permite acrescentá-los à lista de elementos determináveis. Os métodos foram validados pela análise de um conjunto de materiais de referência (MR), alguns deles certificados. Os resultados obtidos demonstraram que os métodos desenvolvidos para águas e rochas apresentaram tendência e coeficientes de variação menores que 5% para a maior parte dos mensurandos. Os resultados obtidos para os MR certificados de rochas, BRP-1 e OU-6, foram utilizados para calcular a incerteza do método ao nível aproximado de confiança de 95%. A técnica de diluição isotópica foi aplicada para determinar Cr, Ni, Cu, Zn, Sr e Sn em alguns MR de rochas em uso e em candidatos a MR, com o objetivo de estabelecer o método e contribuir com novos valores para esses MR. As incertezas de todas as etapas do procedimento foram estimadas. Os resultados obtidos evidenciam que o valor certificado de Cr em BRP-1 deveria ser revisto e confirmam a necessidade do estabelecimento da rastreabilidade metrológica durante a certificação de MR. / Abstract: Inductively coupled plasma mass spectrometry (ICP-MS) is suited for fast multi-trace element determinations with low detection limits in a variety of matrices, including geological samples. In this study we established comparative analytical methods for the determination of an expressive number of trace elements in water and rock samples using an ICP-MS equipped with collision cell (CC). The applicability and limitations of CC for polyatomic interference attenuation over the isotopes used were widely investigated. Under optimized conditions, many interferences were eliminated or significantly attenuated, so these methods depend less on mathematical corrections. For rock analyses, classical multi-acid decomposition techniques, with mixtures like HF/HNO3, were used, and a new procedure with equipment that allows digestion at 13 MPa is proposed. In this case, the precipitation of AlF3, which retains some trace elements like Co, Sr, Ba and Pb preferentially, was the major drawback in achieving quantitative recoveries. The formation of AlF3 was inhibited by adding Mg to the test portion and controlling the temperature of digestion. Sample decomposition by sintering with sodium peroxide was also tested and was demonstrated that including a heating step of the sinter dispersion obtained after dissolution in water and before the separation of the precipitated Fe and Ti hydroxides, which retain many trace elements, helps to achieve a quantitative co-precipiation of Ni, Zr, Nb, Cd, Sn, Sb, Hf, Pb and Th and allows to include them to the list of determinable elements. The methods were validated by analysis of a set of reference materials (RM) some of them certified. Relative standard deviations and bias of the results were less than 5% for most of the measurands. The results obtained for the certified RM BRP-1 and OU-6 were used to calculate the measurement uncertainty at the approximate 95% confidence interval. The isotope dilution technique was applied to determine Cr, Ni, Cu, Zn, Sr and Sn in some geochemical RM in use and in candidate RM, with the objective of establishing the method to contribute with new values for the analysed RM. The uncertainties of the whole analytical procedure were estimated. The results obtained show that the certified value of Cr in BRP-1 should be reviewed and confirm the need of establishing the metrological traceability during the certification of RM. / Doutorado / Geologia e Recursos Naturais / Doutor em Ciências

De nombreux sols forestiers français sont acides et pauvres en éléments nutritifs et les forêts françaises font face aujourd'hui à des pressions extérieures croissantes. Ces nouvelles contraintes sont d'ordre nutritionnel et/ou sylvicole et/ou climatique et risquent d'impacter la durabilité des écosystèmes forestiers à faible fertilité minérale. Il est donc très important de comprendre et quantifier les processus qui régissent les cycles des éléments nutritifs dans ces écosystèmes afin de prédire au mieux leurs évolutions possibles face à de telles contraintes et ainsi aider les gestionnaires forestiers à prendre des décisions réfléchies pour assurer leur durabilité. L'objectif principal de cette thèse était de comprendre le cycle du calcium et du magnésium dans un écosystème forestier productif bien que croissant sur un sol très faiblement pourvu en Ca et Mg. Pour cela, nous avons établi dans un peuplement de hêtre âgé de 35 ans des bilans de flux « entrées-sorties » basés sur des mesures classiques de pools et flux entre 2003 et 2008. Puis une expérience de multi-traçage isotopique (2H, 15N, 26Mg et 44Ca) a ensuite été conduite: les traceurs ont été apportés à la surface du sol en avril 2010 sous forme soluble et leur progression a été suivie dans l'écosystème jusqu'en mars 2012. Les résultats ont mis en évidence le rôle primordial que joue la matière organique dans les cycles du Mg et du Ca, en leur conférant notamment un caractère très conservatif. Le 26Mg et le 44Ca apportés ont été captés dans la fine couche de litière au sol puis lentement libérés. Dans les horizons minéraux, la matière organique du sol, qui semble contribuer à la plus grande part de CEC du sol, a fortement contribué à ralentir la migration du Mg et du Ca à travers le sol. Par rapport au Mg, le calcium apporté a été plus intensément retenu dans la litière, et moins intensément lixivié à travers le sol en raison de sa plus grande affinité pour la matière organique. Malgré les flux préférentiels d'eau mis en évidence par le traçage au 2H, aucune perte par drainage de 26Mg ou 44Ca n'a été mesurée. Deux années après l'apport, il restait dans la litière 8% du 26Mg et 33% du 44Ca apportés tandis que, respectivement, 52% et 46% ont été retrouvés dans les 10 premiers cm du sol. Les traceurs, rapidement absorbés par les racines fines ont migré dans l'arbre à des vitesses très différentes: les feuilles étaient enrichies en 15N dès le mois suivant l'apport des traceurs, tandis que seuls de très faibles enrichissements en 26Mg (mais pas de 44Ca) ont été mesurés dans la canopée en 2012. Le bilan en 2012 montre les arbres ont absorbé 27% de 26Mg et 20% de 44Ca et qu'ils sont majoritairement concentrés dans les tissus de la base du tronc. L'utilisation de traceurs isotopiques a permis de mettre en évidence la lenteur de la redistribution de Mg et encore plus de Ca dans l'écosystème, d'une part de la litière vers les sols et d'autre part des racines vers les canopées. Ce comportement est attribué à l'affinité de ces ions pour les charges carboxyliques portées par la matière organique. Enfin, la dilution isotopique mesurée dans les différents compartiments de l'écosystème à l'issue de deux années a permis de calculer des bilans et ainsi de valider les pertes de Mg calculées par l'approche classique de « bilan de fertilité minérale ». En revanche, les pertes de Ca calculées par cette même approche ont été mises en défaut, démontrant la contribution d'une source externe (absorption par les feuilles, altération…) ou interne (mobilisation du stock des tissus ligneux), non prise en compte dans l'approche classique. L'ensemble de ces travaux souligne l'intérêt de l'approche « traçage isotopique » en complément des approches conventionnelles afin d'étudier la fertilité minérale des écosystèmes forestiers. / Many forest soils in France are acid and nutrient poor. French forests endure today increased external constraints which may be nutritional and/or silvicultural and/or climatic. These constraints may strongly impact the sustainability of nutrient-poor ecosystems. It is thus important to understand and quantify the processes which govern nutrient cycling in these ecosystems to better predict soil fertility changes and help forest managers make sound decisions to sustain these ecosystems.The main objective of this thesis was to study magnesium and calcium cycles in a productive forest ecosystem with low available magnesium and calcium pools in the soils. For this purpose, in a 35-year-old beech stand, we computed input-output nutrient budgets between 2003 and 2008 using conventional approaches to measure nutrient pools and fluxes. A multi-isotopic (2H, 15N, 26Mg et 44Ca) tracing experiment was then carried out in the same plot: tracers were sprayed on the forest floor in April 2010 as soluble salts, tracer transfer was then monitored in the whole ecosystem until March 2012 (litter-layer, exchangeable pools, soil solutions, above-ground biomass…).The results evidenced the predominant role of organic matter in the very conservative cycling of Mg and Ca in this nutrient-poor soil. Indeed, the applied 26Mg and 44Ca were very rapidly retained in the fine litter-layer by ion-exchange processes. In the soil profile, most of the CEC was probably due to soil organic matter which played an important role in the retention of Mg and Ca in the soil. Compared to magnesium, calcium was more strongly retained in the litter layer and transferred more slowly in the soil profile because of the higher affinity of calcium for organic CEC. Despite preferential water flow evidenced by the water tracing experiment (2H), no leaching of 26Mg or 44Ca was observed during the study period. Two years after the application of tracers, 8% of applied 26Mg and 33% of applied 44Ca was still retained in the litter layer while, respectively, 52% and 46% of applied tracers were found in the first 10cm of the soil profile. Tracers were rapidly absorbed by the fine roots but were transferred from the roots to the canopy at very different velocities: leaves were enriched in 15N one month after the application of tracers while only very small 26Mg enrichments and not 44Ca were observed in the canopy in 2012. Tracer budgets in 2012 showed that trees absorbed 27% of 26Mg and 20% of 44Caand that tracers were mainly concentrated at the base of the bole. The use of isotope tracers evidenced the slow distribution of magnesium and the slower distribution of calcium in the ecosystem, on the one hand from the litter pool to the soil profile and on the other hand from the roots to the canopy. This behavior was attributed to the affinity of the cations for organic matter functional groups such as carboxyl groups.Finally the isotopic dilution technique of the applied tracers measured in the different ecosystem compartments after two years of monitoring enabled us to validate the Mg losses computed by nutrient budgets. However, Ca depletion suggested by nutrient budgets were proven to be nil thus evidencing the contribution of an external (foliar absorption, weathering) and/or internal (mobilization of nutrients stored in ligneous tissues) sources which are currently not taken into account in conventional approaches.Overall the results of the in situ ecosystem scale multi-isotopic tracing experiment show the added value of the “isotopic tracing” approach to study nutrient pools and fluxes in forest ecosystems in addition to conventional approaches.

A integração das espécies de adubos verdes, que imobilizam P, com a aplicação de fontes minerais fosfatadas é uma das medidas agronômicas mais promissoras para melhorar a disponibilidade de P para a cultura principal, com o objetivo de recuperar a fertilidade do solo, aumentar a matéria orgânica do solo e assim, otimizar eficiência de fertilizantes minerais. Os objetivos deste trabalho foram selecionar entre as espécies de adubos verdes mais eficientes em absorver o P na forma menos disponível e pela marcação isotópica destas plantas com ³²P, quantificar o aproveitamento deste nutriente proveniente dos adubos verdes e do fertilizante mineral pela cultura da cana-de-açúcar e do arroz, determinando suas reais contribuições como fonte de P. O estudo foi desenvolvido três fases, em amostras de Latossolo Vermelho Amarelo distrófico típico, com baixo teor de P, em casa-de-vegetação no CENA/USP. O primeiro experimento foi realizado com a finalidade de identificar e selecionar entre as 25 espécies de adubos verdes (AV) mais eficientes em absorver P através de métodos de diluição isotópica. As plantas foram cultivadas em delineamento inteiramente casualizado com três repetições. Com os resultados (13 variáveis) das 25 espécies de adubo verde realizou-se análise estatística de componentes principais (PCA) e de agrupamento hierárquico (AHA) visando grupar os mais similares. A PCA foi explicada pelas duas primeiras componentes, definidas como P acumulado na planta e o valor L, resultando em três grupos, sendo o tremoço a espécies mais eficiente em absorver o P menos disponível, portanto, há diferença entre as espécies quanto à absorção. A partir desses grupos foram selecionadas algumas espécies de adubos verdes para avaliar o aproveitamento do P (AP) do adubo verde e do superfosfato triplo (SFT) pela raiz e parte aérea da cana-de-açúcar (experimento II) e pela parte aérea do arroz (experimento III) através da técnica da diluição isotópica. Para a cana-de-açúcar, foram selecionados braquiária ruziziensis, crotalária juncea, guandu anão, estilosante cv. Campo grande e para o arroz, a crotalária juncea e guandu anão e quatro doses de SFT (0; 30; 60 e 120 mg/vaso de P). Em média, os AVs apresentaram baixo aproveitamento, sendo 0,1 % pela raiz da cana; 0,8% pela parte aérea da cana e 2,0% pelo arroz. Para SFT, o AP pela raiz da cana foi de 1,0%; 9,9% pela parte aérea e 4,0% pelo arroz. Assim, o AP do SFT é superior aos dos adubos verdes para as duas culturas, independente das espécies de adubos verdes. Obtêm-se maior aproveitamento do SFT para ambas as culturas, na dose de 30 mg/vaso de P. O P do adubo verde não é suficiente para suprir a total demanda da cultura principal, mas favorece a absorção do P pela cultura quando associada ao SFT. / Integration of green manures species, which immobilize P, with supplying mineral P sources is one of the most promising agronomic practices for improving the availability of P for the main crop in order to recover soil fertility, increasing soil organic matter and thus optimize the efficiency of mineral fertilizers. The objectives of this work was to select among the green manure species the most efficient in absorbing the less available form of P, and by isotopic labeling of this plants, quantify the use of this nutrient from the green manures and mineral fertilizer by the sugar cane and rice crops, determining their real contributions as a P source. It was developed in three phases, in dystrophic Typical Hapludox, low-P, in the greenhouse in CENA / USP. The first experiment was conducted to identify and select the green manure species the more efficient one in absorbing P by isotopic dilution techniue. The plants were grown in a completely randomized design with three replications. With 25 species of green manures and 13 variables statistical analysis of principal components (PCA) and hierarchical clustering (HCA) were carried out in order to group the most similar ones. The PCA was explained by the first two components, defined as plant accumulated P and the L value, resulting three groups, and the white lupin being the most efficient in absorbing less available P, so there is difference between species on the ability to absorb the less available form of soil P absorption. From these groups some species of green manure were selected to evaluate the P use efficiency (PUE), from green manure and triple superphosphate (TSP), both labeled with ³²P, by sugar cane (experiment II) and rice plant (experiment III) through the isotopic dilution technique. Brachiaria, sunnhemp, dwarf pigeon pea, stylosante cv. campo grande were selected for sugar cane and sunnhemp and dwarf pigeon pea for rice, and four rates of TSP (0, 30, 60 and 120 mg P/ pot). On average, the AVs had low PUE, begin 0.1% by the root of sugar cane, 0.8% by shoot of sugar cane and 2.0% by rice. For TSP, the PUE by sugar cane roots were 1.0%, 9.9% by shoots and 4.0% by rice plants. Thus PUE of TSP is greater than that of green manure for both crops, regardless of green manure species. The highest PUE of TSP for both crops was obtained at rate of 30 mg P/pot. The green manure P is not sufficient to meet total demand for the main crop, but improves the absorption of P by the crop when associated with SFT.

A integração das espécies de adubos verdes, que imobilizam P, com a aplicação de fontes minerais fosfatadas é uma das medidas agronômicas mais promissoras para melhorar a disponibilidade de P para a cultura principal, com o objetivo de recuperar a fertilidade do solo, aumentar a matéria orgânica do solo e assim, otimizar eficiência de fertilizantes minerais. Os objetivos deste trabalho foram selecionar entre as espécies de adubos verdes mais eficientes em absorver o P na forma menos disponível e pela marcação isotópica destas plantas com ³²P, quantificar o aproveitamento deste nutriente proveniente dos adubos verdes e do fertilizante mineral pela cultura da cana-de-açúcar e do arroz, determinando suas reais contribuições como fonte de P. O estudo foi desenvolvido três fases, em amostras de Latossolo Vermelho Amarelo distrófico típico, com baixo teor de P, em casa-de-vegetação no CENA/USP. O primeiro experimento foi realizado com a finalidade de identificar e selecionar entre as 25 espécies de adubos verdes (AV) mais eficientes em absorver P através de métodos de diluição isotópica. As plantas foram cultivadas em delineamento inteiramente casualizado com três repetições. Com os resultados (13 variáveis) das 25 espécies de adubo verde realizou-se análise estatística de componentes principais (PCA) e de agrupamento hierárquico (AHA) visando grupar os mais similares. A PCA foi explicada pelas duas primeiras componentes, definidas como P acumulado na planta e o valor L, resultando em três grupos, sendo o tremoço a espécies mais eficiente em absorver o P menos disponível, portanto, há diferença entre as espécies quanto à absorção. A partir desses grupos foram selecionadas algumas espécies de adubos verdes para avaliar o aproveitamento do P (AP) do adubo verde e do superfosfato triplo (SFT) pela raiz e parte aérea da cana-de-açúcar (experimento II) e pela parte aérea do arroz (experimento III) através da técnica da diluição isotópica. Para a cana-de-açúcar, foram selecionados braquiária ruziziensis, crotalária juncea, guandu anão, estilosante cv. Campo grande e para o arroz, a crotalária juncea e guandu anão e quatro doses de SFT (0; 30; 60 e 120 mg/vaso de P). Em média, os AVs apresentaram baixo aproveitamento, sendo 0,1 % pela raiz da cana; 0,8% pela parte aérea da cana e 2,0% pelo arroz. Para SFT, o AP pela raiz da cana foi de 1,0%; 9,9% pela parte aérea e 4,0% pelo arroz. Assim, o AP do SFT é superior aos dos adubos verdes para as duas culturas, independente das espécies de adubos verdes. Obtêm-se maior aproveitamento do SFT para ambas as culturas, na dose de 30 mg/vaso de P. O P do adubo verde não é suficiente para suprir a total demanda da cultura principal, mas favorece a absorção do P pela cultura quando associada ao SFT. / Integration of green manures species, which immobilize P, with supplying mineral P sources is one of the most promising agronomic practices for improving the availability of P for the main crop in order to recover soil fertility, increasing soil organic matter and thus optimize the efficiency of mineral fertilizers. The objectives of this work was to select among the green manure species the most efficient in absorbing the less available form of P, and by isotopic labeling of this plants, quantify the use of this nutrient from the green manures and mineral fertilizer by the sugar cane and rice crops, determining their real contributions as a P source. It was developed in three phases, in dystrophic Typical Hapludox, low-P, in the greenhouse in CENA / USP. The first experiment was conducted to identify and select the green manure species the more efficient one in absorbing P by isotopic dilution techniue. The plants were grown in a completely randomized design with three replications. With 25 species of green manures and 13 variables statistical analysis of principal components (PCA) and hierarchical clustering (HCA) were carried out in order to group the most similar ones. The PCA was explained by the first two components, defined as plant accumulated P and the L value, resulting three groups, and the white lupin being the most efficient in absorbing less available P, so there is difference between species on the ability to absorb the less available form of soil P absorption. From these groups some species of green manure were selected to evaluate the P use efficiency (PUE), from green manure and triple superphosphate (TSP), both labeled with ³²P, by sugar cane (experiment II) and rice plant (experiment III) through the isotopic dilution technique. Brachiaria, sunnhemp, dwarf pigeon pea, stylosante cv. campo grande were selected for sugar cane and sunnhemp and dwarf pigeon pea for rice, and four rates of TSP (0, 30, 60 and 120 mg P/ pot). On average, the AVs had low PUE, begin 0.1% by the root of sugar cane, 0.8% by shoot of sugar cane and 2.0% by rice. For TSP, the PUE by sugar cane roots were 1.0%, 9.9% by shoots and 4.0% by rice plants. Thus PUE of TSP is greater than that of green manure for both crops, regardless of green manure species. The highest PUE of TSP for both crops was obtained at rate of 30 mg P/pot. The green manure P is not sufficient to meet total demand for the main crop, but improves the absorption of P by the crop when associated with SFT.

The work presented in this dissertation explores the nature of agro-pastoral strategies developed by Neolithic farmers as a way to understand how early food production was inter-twined with environmental and socio-economic opportunities and constraints. Towards this end, a multi-isotope approach is used to address questions of scale and intensity of crop cultivation and animal management at the archaeological sites of Kouphovouno, southern Greece, Makriyalos, northern Greece, and Çatalhöyük, south-central Turkey. Measurements of stable carbon, nitrogen, oxygen and strontium isotope values of carbonized plant remains, human and animal bone collagen and animal tooth enamel are used to examine the similarities and differences in the types of treatments that individual species of plants and animals received during the agricultural cycle at the distinct locations. The results show that farmers at the three sites developed variable methods for exploiting the arable and pastoral landscape and catering to their economic and culinary needs. The discussion considers the implications of these findings to our understanding of the complexity and adaptability of early farming systems.

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[pt] Os metais estão presentes em diversos materiais e muitos deles, como o níquel e o cromo, possuem papeis significativos em diversos setores industriais. A quantificação desses metais é importante tanto para obtenção de informações relevantes a respeito desses materiais, como para avaliação de possíveis contaminações ambientais. No presente trabalho, foram desenvolvidos métodos analíticos para a determinação de níquel e cromo em amostras de asfalto, brita e CAP por espectrometria de massa com plasma indutivamente acoplado usando calibração externa e diluição isotópica. Para a avaliação da exatidão dos métodos foram utilizados os materiais de referência certificados NIST 1084a e NBS 688. Como métodos de preparo de amostra, foram estudadas a decomposição ácida em bloco digestor, e a diluição em uma mistura de xileno/butanol na proporção 60:40 v:v (para amostras de óleo). Para a correção da interferência da espécie 40Ar12C positivo sobre o isótopo de 52Cr foi utilizada a célula de reação dinâmica com introdução de CH4 como gás de reação, o que reduziu de forma significativa o sinal de fundo característico para o isótopo de cromo. Os métodos desenvolvidos se mostraram eficientes na determinação dos metais. As recuperações obtidas para os SRMs se encontram entre 80-120 porcento. As concentrações médias, em mg kg-1 , encontradas para Ni pelos diferentes métodos nas amostras de CAP, brita e asfalto foram, respectivamente 39,9 mais ou menos 0,6, 6,7 mais ou menos 0,5 e 11,2 mais ou menos 0,8, enquanto para Cr as concentrações foram 1,8 mais ou menos 0,1, 15,3 mais ou menos 0,3, 16,6 mais ou menos 0,4. O sucesso da aplicação da diluição isotópica em amostras dissolvidas em solvente orgânico mostrou-se muito promissor, pois elimina a necessidade da decomposição ácida das matrizes tornando o preparo das amostras mais rápido e menos trabalhoso. / [en] Metals are present in several samples and many of them, such as nickel and chromium, have significant roles in several industry sectors. The quantification of these metals is important both for obtaining relevant information regarding these materials, and for evaluating possible environmental contaminations. In the present work, analytical methods were developed for the determination of nickel and chromium in asphalt, crushed stone and CAP samples by inductively coupled plasma mass spectrometry using both external calibration technique and isotopic dilution. To evaluate accuracy of the method, the certified reference materials NIST 1084a and NBS 688 were used. Two different methods of sample preparation were employed, block digestion and direct dilution in a xylene / butanol mixture using a 60:40 v:v ratio (for the oil samples). For the interference correction imposed by 40Ar12C over 52Cr, the dynamic reaction cell was used with CH4 as the reaction gas, which significantly reduced the characteristic background signal of the chromium isotope. The methods developed proved to be efficient in the determination of the metals in question. The recovery values obtained for the SRMs were between 80-120 percent. The average concentrations, in mg kg-1 , found for Ni by the different methods in CAP, crushed stone and asphalt samples were, respectively, 39,9 more or less 0,6, 6,7 more or less 0,5 and 11,2 more or less 0,8, while for Cr the concentrations were 1,8 more or less 0,1, 15,3 more or less 0,3, 16,6 more or less 0,4. The successful application of isotope dilution in samples dissolved in organic solvent is very promising because it eliminates the need for acid digestion, making the sample preparation faster and less labor intensive.

Im Rahmen dieser Arbeit wurden vier verschiedene Methoden zur Separation, Identifikation sowie Quantifizierung von Silber-Nanopartikeln (Ag-NP) entwickelt. Mittels asymmetrischer Fluss-Feldflussfraktionierung (AF4) in Kombination mit einem induktiv gekoppelten Plasma-Massenspektrometer (ICP-MS) konnten eine gute Trennung und hohe Wiederfindungsraten gefunden werden. Eine systematische Studie möglicher Probenverluste während der Methodenoptimierung zeigte, dass der größte Verlust durch die Ag+-Ionen verursacht wurde, während Verluste durch Ablagerungen auf der Membran vernachlässigbar waren. Für Citrat-stabilisierte Ag-NP konnten mittels Hohlfaser-Fluss-Feldflussfraktionierung (HF5) gute Trennergebnisse erreicht und der hydrodynamische Durchmesser bestimmt werden. Zur Bestimmung der Partikelanzahlgrößenverteilung und des geometrischen Durchmessers von Partikeln in unbekannter Matrix wurde die Isotopenverdünnungsanalyse (IVA) erfolgreich mit der Einzelpartikel ICP-MS kombiniert. Weiterhin wurde eine Hochdruckflüssigkeitschromatographie(HPLC)-IVA-ICP-MS-Methode entwickelt, mit welcher NP und ihre korrespondierenden Ionen getrennt und quantifiziert werden konnten. Ein Vergleich der Ansätze zeigt, dass eine Kombination mehrerer Methoden nötig ist, um alle relevanten Informationen über die NP zu erhalten. Zum Abschluss wurde mit den entwickelten Methoden das Umweltverhalten der Ag-NP in einer Huminsäure(HS)-Suspension untersucht. Hierbei wurden erste Stabilisierungseffekte in Bezug auf die Ag-Konzentration und Partikelanzahl festgestellt. Zudem konnte mittels HF5 und HPLC für kleine NP in HA eine Modifikation in Form der Ausbildung eines zweiten, kleineren NP-Signals beobachtet werden. / In this work, four different methods for the separation, identification, and quantification of silver nanoparticles (Ag-NP) were developed. Using asymmetric flow field-flow fractionation (AF4) in combination with inductively coupled plasma mass spectrometry (ICP-MS), a good separation and high recovery rates were found. A systematic investigation of possible sample losses during the method optimization showed that Ag+ ions caused the highest loss and only negligible amounts of Ag residues on the membrane were found. For citrate-stabilized Ag-NP, hollow fiber flow-field flow fractionation (HF5) analyses achieved good results for the separation and calculation of the hydrodynamic diameters. In order to determine the particle number size distribution and the geometric diameter for samples in unknown matrices, isotope dilution analysis (IVA) was successfully combined with single particle ICP-MS. Additionally, a high-performance liquid chromatography (HPLC)-IVA-ICP-MS approach was developed, which was able to separate and quantify NP and their corresponding ions. A comparison of the methods showed that a combination of different approaches is necessary to obtain all relevant information. Finally, the methods were applied to analyze the environmental behavior of Ag-NP in a humic acid (HS) suspension. Here, first stabilization effects in terms of the Ag concentration and particle number concentration were detected. Using HF5 and HPLC for the analysis of small NPs in HS, a modification in the form of a second, smaller NP signal was observed.