L'activité agricole peut entraîner un déséquilibre des cycles du carbone (C) et de l'azote (N) dans les écosystèmes terrestres naturels et entrainer une diminution des stocks de C et N dans le sol, une augmentation de la lixiviation du nitrate et des pertes d'azote par voie gazeuse. Pour réduire ces impacts environnementaux, la mise en place de systèmes agricoles innovants et durables est encouragée, tels que les systèmes à bas niveau intrants, l'agriculture de conservation ou l'agriculture biologique. Les objectifs de cette thèse sont i) de quantifier l'impact à long terme des différents systèmes de culture sur le devenir du carbone et de l'azote dans le système sol-plante-atmosphère et ii) de simuler la dynamique de ces éléments avec le modèle agro-environnemental STICS. À cette fin, nous avons étudié trois essais de longue durée : l'essai de La Cage (France) établi en 1998, l'essai DOK (Suisse) débuté en 1978 et l'essai Foulum (Danemark) créé en 1998. Alors que l'essai de La Cage a permis une quantification in situ du stockage du carbone et de l'azote organiques du sol, de la lixiviation de l'azote, des émissions de protoxyde d’azote (N2O) et de la balance des gaz à effet de serre pour des systèmes de culture alternatifs, les essais danois et suisses ont permis l'estimation in silico du devenir du C et N en agriculture biologique, après adaptation du modèle STICS pour simuler de nouvelles pratiques culturales. Après 16 années d’expérimentation, une accumulation annuelle significative de SOC et de SON a été observée en agriculture et en agriculture biologique à La Cage, alors qu'aucun changement significatif n'a été observé dans les systèmes conventionnels et bas intrants. La minéralisation spécifique de SOC et SON des quatre systèmes, simulée sur AMG et mesurée lors d’incubation des sols pendant quatre mois, s’est montrée équivalente entre systèmes. Le stockage de C et N observé dans les systèmes de conservation et biologiques s’explique principalement par l'augmentation des résidus de cultures plutôt que par l'effet du non-labour en agriculture de conservation. De plus, le surplus azoté (différence entre apports et exportations d’azote) a été calculé pour chaque système de culture. Le devenir de l’excédent d’azote a été estimé entre stockage de N dans le sol, pertes gazeuses et lixiviation de l'azote. Les émissions cumulatives de N2O mesurées en continu pendant plus de trois ans sont fortement corrélées avec les pertes totales calculées de N par voix gazeuse (volatilisation et dénitrification), ces pertes étant les plus importantes dans le système de conservation. Enfin, la réalisation d’un bilan complet des émissions de GES a montré de fortes différences entre système et des phénomènes de compensation entre stockage et perte de C et N. Le modèle sol-culture STICS a ensuite été utilisé pour simuler le devenir de l’azote dans les essais DOK et Foulum. Après une adaptation du modèle, sa calibration et son évaluation ont été réalisées permettant de simuler de façon satisfaisante les rendements, l'absorption de N, le surplus de N et l’évolution des stocks de SON dans les systèmes conventionnels et biologiques. Les simulations suggèrent que le devenir de l’azote dans ces systèmes peut être contrasté en fonction de la fertilisation et de la gestion des cultures et que les pertes d'azote ne sont pas systématiquement réduites en agriculture biologique par rapport au conventionnel. Cette thèse remet en question les appréciations simplistes qui associent systématiquement systèmes de culture alternatifs et diminution des impacts environnementaux liés aux cycles de C et N / Agricultural activities can lead to imbalanced carbon (C) and nitrogen (N) dynamics compared to natural terrestrial eco-systems, causing potential damages for soil, water and air quality. Among these prejudices, decreased soil C and N stocks, increased nitrate leaching in waters and gaseous N emissions towards the atmosphere are of a major concern. To reduce these environmental impacts, innovative and sustainable farming systems are promoted, such as low inputs cropping systems, “conservation” agriculture or organic farming. The objectives of this work were i) to quantify the long term impact of different alternative cropping systems on the fate of C and N in the soil-plantatmosphere system and ii) to simulate C and N dynamics with the agro-environmental model STICS. For this purpose, we studied three long-term field trials: the experiment of La Cage (France) established in 1998, the DOK (Switzerland) started in 1978 and the Foulum Organic (Denmark) established in 1998. The methodological approach combined experimentation and modelling. While La Cage trial enabled an in situ quantification of soil organic C and N storage, N leaching, nitrous oxide (N2O) emissions and greenhouse gas (GHG) balance in alternative cropping systems compared to conventional, the Swiss and Danish experiments were used for in silico estimation of the C and N fates in organic cropping systems, after adaptation of the STICS model, followed by calibration and evaluation of the model. Significant annual SOC and SON accumulation was found under conservation agriculture and organic farming at La Cage, whereas no significant change was observed in the low input and the conventional systems. No difference of specific SOC and SON mineralization rates was found between systems in vitro or in silico : we conclude that the higher C and N storage in soil observed in the conservation and organic systems was mainly driven by increased crop residues, rather than by the effect of no tillage practiced in conservation agriculture. The N surplus, i.e. the difference between N inputs and N exports at the field scale, varied widely between treatments. The fate of this N surplus also varied between systems with wide variations in SON storage and gaseous losses but no differences in N leaching. The cumulative N2O emissions measured continuously for three years were highly correlated with the calculated gaseous N losses (volatilization and denitrification), with higher losses in the conservation system. These calculations allowed establishing a full GHG balance. Therefore the four agricultural systems dissimilarly impacted the N fate, which could not be predicted by the N surplus alone. The GHG balance is a much better indicator of the environmental impact of cropping systems relative to C and N fluxes. In the Danish and Swiss experiments, the soil-crop model STICS was used to mimic crop production, N uptake and N surplus. The model was first adapted and evaluated to simulate organic farming systems. The model could satisfactorily simulate crop production, N uptake, N surplus and SON storage in the organic and conventional systems of these two longterm experiments. Model outputs suggested that the N fate could be contrasted according to fertilization and crop management, and that N losses were not systematically reduced in organic compared to conventional cropping systems. This study challenges the frequent belief that alternative cropping systems systematically improve the global C and N environmental impacts of agriculture.

Devido ao seu elevado teor de nutrientes e potencial de neutralização da acidez do solo, a utilização de lodos de curtume em áreas agrícolas tem sido uma alternativa para disposição e reciclagem desses resíduos. Por outro lado, o aumento do pH e do teor de nitrogênio amoniacal no solo, quando da aplicação superficial do lodo de curtume, podem favorecer a perda de nitrogênio (N) por volatilização da amônia (NH3). Altos teores de nitrogênio inorgânico no solo podem gerar efeitos negativos, principalmente quando a amonificação e nitrificação não são sincronizadas com a absorção pelas plantas, possibilitando lixiviação e conseqüente contaminação das águas subsuperficiais. Um experimento de campo foi instalado em Rolândia (PR) com os objetivos de avaliar a perda de nitrogênio por volatilização da amônia, as alterações em alguns atributos microbiológicos do solo envolvidos no ciclo do nitrogênio e carbono, a lixiviação de nitrogênio mineral no solo, a produtividade da cultura de milho e o efeito residual, após a aplicação de doses crescentes de lodo de curtume no solo. O delineamento experimental foi de blocos completos casualizados, com quatro repetições. As doses de lodo foram calculadas em função do teor de N total contido no lodo de curtume. Os tratamentos foram: controle, 120, 480, 840 e 1200 kg ha-1 de N total adicionados via lodo de curtume, correspondendo, respectivamente, a 0, 3,4, 13,5, 23,6 e 33,7 Mg ha-1 de lodo de curtume (base seca). O lodo foi aplicado na superfície de um Nitossolo Vermelho distroférrico, muito argiloso, onde permaneceu por 89 dias, período em que foi determinada a perda de amônia por volatilização. Em seqüência, o lodo foi incorporado, com posterior semeadura da cultura de milho. Nesse momento foi instalado um tratamento adicional (Tratamento agronômico - 120 kg ha-1 N via uréia). Após a colheita do milho, a aveia preta foi semeada em sistema direto, sendo conduzida até o estádio de florescimento. Durante todo o período experimental foram realizadas coletas de solo nas camadas de 0-10, 10-20, 20-40, 40-60 cm e solução do solo nos tratamentos controle, 120 e 1200 kg ha-1 N total via lodo, a 1,2 m de profundidade. A volatilização da amônia foi mais intensa nos 30 primeiros dias após a aplicação, decaindo depois desse período. A fração volatilizada como NH3 correspondeu, em média, a 17,5% do N total contido no lodo de curtume. A densidade dos grupos funcionais de microrganismos, respiração do solo e atividade enzimática apresentaram aumentos transientes após aplicação de lodo de curtume. Dentre os atributos avaliados, as enzimas glutaminase, urease e asparaginase mostraram maior atividade em resposta à aplicação de lodo de curtume. A dose 120 kg ha-1 de N via lodo de curtume não apresentou risco de contaminação do lençol freático, enquanto que na maior dose (1200 kg ha-1 N total) o teor de nitrato na solução do solo coletada a 1,2 m foi até 12 vezes maior que no controle. A dose de 521 kg ha-1 de N total proporcionou ganhos de produtividade de grãos de 13% e 11% em relação ao controle e ao tratamento agronômico, respectivamente. Foi observado efeito residual sobre a massa de matéria seca da parte aérea da aveia preta 390 dias após a aplicação do lodo. Ou seja: Doses elevadas de lodo de curtume (equivalentes a altas doses de N), aplicadas ao solo, podem resultar em poluição do ar e das águas subsuperficiais. / Due to its high nutrient content and its neutralizing potential for soil acidity, the utilization of tannery sludge in agricultural areas can be an alternative for its disposal and recycling. On the other hand, the pH and ammonia nitrogen content increase in soil as a result of surface tannery sludge application and may induce the loss of nitrogen (N) by ammonia (NH3) volatilization. The high N content in soils can generate negative effects, mainly when the organic N ammonification and nitrification does not coincide with the plant N uptake, allowing the nitrate to leach through the soil profile to the groundwater. A field experiment was installed in Rolândia (Paraná State, Brazil). The aims of this experiment were to evaluate the N loss through ammonia volatilization, changes in soil microbial attributes that are linked to the carbon and N cycles, mineral N leaching through the soil profile, corn yield and the residual effect as affected by tannery sludge application on the soil surface. A randomized complete block design was used with four replicates. The tannery sludge treatments were: control, 120, 480, 840 and 1200 kg ha-1 total N applied as tannery sludge, equivalent to 0, 3.4, 13.5, 23.6 and 33.7 Mg ha-1 tannery sludge (dry weight). The tannery sludge was surface applied on a clayey Rhodic Kandiudult. The tannery sludge was left on the soil surface for 89 days, and during this period the N loss through NH3 volatilization was determined. Afterwards, tannery sludge was incorporated and the corn was sown. At this moment, an additional treatment (agricultural treatment - 120 kg ha-1 N as urea) was applied. After the corn harvest, black oat was sown and carried on until flowering. Soil samples were taken at the following depths: 0-10, 10-20, 20-40 and 40-60 cm for all treatments. Soil solution was extracted at 1.2 m soil depth only in the control, 120 and 1200 kg ha-1 total N treatments. NH3 volatilization was more intense during the beginning of the experiment (30 days). The volatilized fraction as NH3 corresponded in average to 17.5% of the total N of the tannery sludge. The functional microorganism density, soil respiration and enzyme activity showed transient increases after tannery sludge application. The glutaminase, urease and asparaginase enzymes showed a more pronounced increase in activity in response to tannery sludge application. The lowest dose of 120 kg ha-1 total N did not show a contamination risk to the groundwater, while in the highest dose (1200 kg ha-1 total N), the amount of nitrate detected at 1.2 m was 12 times higher than in the control. The dose of 521 kg ha-1 total N corresponded to the maximum corn yield and caused increases of 13% and 11%, when compared to the control and to the agricultural treatment, respectively. Even after 390 days, a residual effect of tannery sludge application was observed as an increase in shoot dry matter of black oat. In short: it was demonstrated that high doses of tannery sludge (equivalent to high doses of total N), applied to soil, result in prohibitively high values of air and ground water pollution.

This research explored different catalytic cracking zeolite additives to improve propylene selectivity and minimize dry gas yield. A comprehensive study of the effect of zeolite structure, pore system and crystal size on maximizing propylene production in FCC unit and the effect of post synthetic modifications on the physicochemical properties and cracking activity of ZSM-5 was investigated using X-ray diffraction (XRD), pyridine adsorption fourier transform infra-red (FTIR), 27Al and 29Si magic-angle spinning nuclear magnetic resonance (MAS NMR) and the catalytic cracking using n-heptane, as a model compound for heavy naphtha. The catalytic performances of these additives were evaluated in a fixed-bed reactor unit using n-heptane as a model compound for naphtha at temperatures 450 - 500 oC and W/F 38 - 92 gcat.h/mol. A range of zeolites were tested with ZSM-5 showing the optimum results at high feed conversion. Further studies on ZSM-5 crystal size illustrated that nano ZSM-5 (300 nm) was superior compared to the regular ZSM-5 (2000 - 4000 nm) in achieved conversion level and propylene selectivity. These improvements were attributed to the shorter path lengths for the reactant reducing diffusion constraints significantly. Modifying nano ZSM-5 acidity using steaming, acid leaching and silanation showed significant improvement over nano ZSM-5 parent. Mild steaming of nano ZSM-5 improved both n-heptane conversion and propylene selectivity whilst severe steaming only improved propylene selectivity. This work attempted to address the often discussed catalytic activity enhancement from mild steaming and identified newly created moderate acid sites as the source of increased activity. Dealumination by acid leaching decreased the total aluminium content of nano ZSM-5 and changed the Brønsted/Lewis ratio. Increasing the B/L ratio, increased the conversion and propylene selectivity. In addition, this research focussed for the first time on the silanation of nano ZSM-5 and its effect on n-heptane cracking, in particular, propylene and dry gas selectivity. Silica was deposited on the external surface of nano ZSM-5 neutralising the acidic sites and as a result, dry gas yield was significantly decreased due to the elimination of non-selective cracking. However, the trade off with conversion was high.

La connaissance des processus de mobilisation et de migration de l’uranium dans les milieux souterrains est un enjeu majeur pour évaluer les risques environnementaux associés aux activités anciennes ou actuelles d'installations nucléaires en vue d'anticiper et gérer tout impact environnemental. La mobilisation et la migration sont habituellement décrites comme fortement contrôlées par les réactions d'adsorption, la présence de ligands, notamment sous forme colloïdale, étant susceptible de l'augmenter considérablement. La capacité des entités colloïdales à transporter l'uranium sur de longues distances va dépendre de leur origine, de leur composition, de leur structure, de leur stabilité et de leur réactivité, ainsi que de leur capacité à complexer l'uranium de manière forte et irréversible. Cependant, les faibles concentrations colloïdales dans les eaux souterraines s’avèrent parfois être un verrou analytique à la détection et à la caractérisation de la mobilisation et du transport colloïdaux de polluant(s) dans les eaux souterraines. Les protocoles d'extraction des phases colloïdales depuis les sols ou les méthodes destinées à concentrer les colloïdes depuis un échantillon d'eau souterraine ne sont pas toujours optimisés pour à la fois assurer un rendement d'extraction satisfaisant et respecter l'intégrité physiques et chimiques des entités colloïdales.Dans ce contexte, deux axes de recherche ont été définis dans ce travail de thèse afin 1) d’appréhender l’impact de l’utilisation de méthodes de préconcentration sur la phase colloïdale et 2) d’améliorer notre compréhension de la dynamique de mobilisation de l’uranium au sein d’un sol podzolisé et ainsi améliorer les modèles prédictifs du transport colloïdal de l’uranium dans les eaux souterraines.Les méthodes de séparation membranaires permettent de préconcentrer la phase colloïdale des eaux souterraines tout en assurant un recouvrement supérieur à 80%. Elles engendrent néanmoins des modifications des paramètres intrinsèques des entités colloïdales avec en particulier un décalage vers les grandes tailles de la distribution en taille de ces entités ainsi qu’une modification de la distribution des espèces entre phases dissoute et colloïdale. Ces modifications peuvent mener à une mauvaise appréciation non seulement des concentrations colloïdales mais aussi des mécanismes de complexation/sorption impliquant la surface des entités colloïdales et de leur stabilité dans les eaux souterraines. La matière organique constitutive des eaux du sol d’étude a été identifiée comme étant le vecteur principal de la remobilisation de l’uranium dans les eaux de sol, sans toutefois avoir un contrôle total de ce processus. Elle est constituée majoritairement d’acides fulviques et humiques de petite taille qui tendent à s’agglomérer au cours du temps, lors de la lixiviation du sol. La composition moléculaire de la matière organique varie de manière temporelle à la fois à l’échelle de l’horizon superficiel mais aussi le long du profil de sol. Divers processus (réduction, dénitrification…) interviennent durant la migration de la matière organique vers les horizons plus profonds et pourraient modifier ainsi sa nature. A l’échelle de l’horizon superficiel, les mécanismes de mobilisation diffèrent selon l’élément considéré. L’uranium en particulier est mobilisé rapidement mais de manière limitée (<2% du sol considéré), tandis que la matière organique est générée en continu et de manière pseudo-linéaire. / Knowledge of the processes of mobilization and migration of uranium in underground environments is a major challenge to assess the environmental risks associated with ancient or current activities of nuclear facilities in order to anticipate and manage any environmental impact. Mobilization and migration are usually described as strongly controlled by adsorption reactions, the presence of ligands, especially in colloidal form, being able to increase considerably. The ability of colloidal entities to transport uranium over long distances will depend on their origin, composition, structure, stability and reactivity, as well as their ability to complex uranium in a significant and irreversible manner. However, low colloidal concentrations in groundwater sometimes prove to be an analytical lock on the detection and characterization of colloidal mobilization and transport of pollutant(s) in groundwater. Protocols for extracting colloidal phases from soils or methods for concentrating colloids from a groundwater sample are not always optimized to both ensure satisfactory extraction yield and respect physical and chemical integrity colloidal entities.In this context, two lines of research have been defined in this thesis work to 1) to understand the impact of the use of preconcentration methods on the colloidal phase and 2) to improve our understanding of mobilization dynamics of uranium within a podzolized soil and thus improve predictive models of colloidal uranium transport in groundwater.The membrane separation methods make it possible to preconcentrate the colloidal phase of the groundwater while ensuring a recovery greater than 80%. Nevertheless, they cause modifications of the intrinsic parameters of the colloidal entities with, in particular, a shift towards the large sizes of the size distribution of these entities as well as a modification of the species distribution between dissolved and colloidal phases. These modifications may lead to an inaccurate appreciation not only of colloidal concentrations but also of complexation/sorption mechanisms involving the surface of colloidal entities and their stability in groundwater. The constituent organic matter of the study soil waters has been identified as the main vector for the remobilization of uranium in the soil water, without having a complete control of this process. It consists mainly of small fulvic and humic acids that tend to agglomerate over time, during leaching of the soil. The molecular composition of organic matter varies temporally both at the level of the superficial horizon and also along the soil profile. Various processes (reduction, denitrification ...) occur during the migration of organic matter to deeper horizons and could thus change its nature. At the level of the superficial horizon, mobilization mechanisms differ according to the element considered. Uranium in particular is mobilized quickly but in a limited way (<2% of the considered soil), while organic matter is generated continuously and in a pseudo-linear way.

Made available in DSpace on 2014-06-11T19:22:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-09-06Bitstream added on 2014-06-13T18:07:57Z : No. of bitstreams: 1 biscaro_t_me_botfca.pdf: 707769 bytes, checksum: a5322c5ecf4e0883a2d95b9be40fdd31 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Em algumas condições não se têm obtido correlações entre os teores de B do solo, extraído com água quente, o teor de boro na planta e a produtividade da soja no Estado do Mato Grosso, mais precisamente na região de Campo Novo do Parecis. Sabe-se que o boro é um nutriente fortemente adsorvido nas partículas minerais do solo. Objetivou-se com este trabalho submeter amostras de solo de uma determinada área de estudo, na qual foi cultivada soja por três anos consecutivos e posteriormente cultivado algodão, a diferentes métodos de extração de boro, a fim de se estabelecer correlações entre a dose de boro na planta, a dose de nutriente aplicada e o teor de boro no solo disponível às plantas e, ainda, com a produtividade da soja. Amostras de solo, cultivadas com soja, coletadas por ocasião da condução do experimento no campo, foram analisadas quanto à concentração de B extraída pelos métodos: água quente modificado com solução de BaCl2 1,25 g L-1 (recomendado e chamado de método da água quente pelo IAC); água quente modificado com solução de CaCl2 0,01 mol L-1,a quente e água quente tradicional (o qual é preconizado por muitos autores como o método oficial) para dessa forma, tentar quantificar a real disponibilidade de boro neste solo, caracterizado como um LATOSSOLO VERMELHO AMARELO (LVA), possibilitando a determinação de um nível crítico. Ainda, durante o período de condução do trabalho, foi feito um estudo de adsorção de B nas amostras, e um estudo do comportamento da lixiviação do nutriente em colunas de solo, procurando verificar o efeito das adubações na dinâmica do nutriente. Em relação aos métodos de extração de boro no solo, o CaCl2 foi o que apresentou correlação positiva e significativa com o boro presente no tecido vegetal nos três anos agrícolas. Os métodos do BaCl2 e... / In some conditions, doesn't have obtained correlations among boron content in soil, boron extracted by hot water, boron content in plants and soybean productivity in a region (Campo Novo do Parecis) of the state of Mato Grosso/Brazil. This work was carried out to submit soil samples from determined area of study where was tillage soybean for three subsequent years and after tillage cotton, to differents extraction methods by boron with the aim to establish correlations among, amount of boron content in plants, amount of nutrient putted in soil, boron content in soil disponible to plants and the productivity. Soil samples obtained during the conduction of experiment on field were analyzed to predict the amount of boron in soil by the methods: hot water modified with BaCl2 solution (recommended and called by hot water from IAC - Instituto Agronômico de Campinas/SP-Brazil), hot water modified CaCl2 0,01 mol L-1 solution and hot water traditional (which is preconized by many authors like the official method) to this way try to quantify the real situation of boron disponibility in this soil, characterized like a Yellow Red Latossol, to take the determination of a critical level. During the conduction period of this work was made an adsorption study in the samples, and still a study of boron leaching behavior in soil columns, to verify fertilizer effect in nutrient dynamic. The extraction method with CaCl2 presented positive and significative correlation with boron present in soybean leaves on three subsequent farm work years. BaCl2 method and hot water traditional also presented positives and significatives correlations each one in two farm work years, this results were expected in function of similarity among three methods, it's an evidence that there is a method with capacity to predict boron disponibility in soils of Mato Grosso... (Complete abstract, click eletronic address below)

La lixiviation en tas est une méthode industrielle utilisée pour traiter des minerais à basse teneur consistant en la percolation d’une solution de lixiviation à travers un tas de 6 à 9 mètres de haut afin d’en extraire l’élément d’intérêt. Cependant, la présence de nombreuses fines particules et d’argiles au sein du minerai peuvent causer l’apparition de phénomènes de colmatage dans les tas, diminuant l’efficacité de la lixiviation. Afin de résoudre ce problème, les industries du nickel, du cuivre ou encore de l’uranium agglomèrent le minerai, augmentant ainsi sa granulométrie par le rassemblement des fines particules. Néanmoins, l’agglomération de minerais uranifères ainsi que l’impact de la structure des agglomérats sur la lixiviation reste peu étudiée. Cette thèse a permis de caractériser l’évolution structurale et pétro physique des agglomérats de minerais d’uranium au cours de la lixiviation, d’étudier l’influence des conditions d’agglomération sur la structure des agglomérats résultants et enfin d’étudier la lixiviation des agglomérats à l’échelle du tas, par le biais d’essais en colonnes métriques. De plus, les causes de colmatage ont pu être identifiées comme provenant d’une dégradation mécanique des agglomérats entrainant une réduction de la perméabilité et de la porosité du tas / Heap leaching allows processing low grade ores. Basically, this industrial mining process consists in percolating a leaching solution slowly down through an ore heap of 6 to 9 meters high to extract the metals of interest. However, fine particles and clays are often the cause of clogging within heaps, leading to a decrease of leaching efficiency. To solve this problem, copper, nickel and uranium industry uses agglomeration of the ore particles. This process allows adjusting the particle size distribution by gathering fine particles. However uranium-ore agglomeration and the impact of the agglomerates structure on heap leaching remains poorly understood. The current thesis allowed characterizing structural and petrophysical properties of agglomerates and its evolution during leaching, studying the influence of agglomeration conditions on agglomerates structures and finally upscaling there results at the heap scale, using meter scale columns. Clogging phenomena were especially due to the mechanical degradation of agglomerates, causing a decrease of both heap porosity and permeability

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No. of bitstreams: 2 Tese - Walter da Costa Mendes - 2016.pdf: 18186028 bytes, checksum: 929f8cf89490e9b207c2c363003c05fa (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-02-25 / The growing global demand for food and a decrease in opening up new areas for expansion due to pressure by environmental preservation, has intensified the process of verticalization of agricultural production, resulting in the shift of extensive to intensive standard. In the Brazilian Cerrado, traditionally with low soil fertility and well defined hydrological cycle, it is observed that this of intensification process has characterized itself by applying large amounts of fertilizer and irrigation. However, mismanagement of irrigation and the doses and times of application of nutrients, especially these with high mobility in soil, can cause losses per leaching, resulting in economic and environmental damage. The objective of this thesis was to quantify the losses of nitrate (NO3-) and potassium (K+), under different managements of irrigation, in sandy and clay soils in greenhouse, and at field, the effects in bean crop irrigated by sprinkling in clay soil. The first experiment was conducted in 2014, Urutaí, Goiás, Brazil. Indeformed soil columns were arranged in a randomized complete blocks design with three replications. As nitrogen source was used calcium nitrate with 15.5% of Total Nitrogen (N) and as source of K+ was used potassium chloride with 58% of K2O. In fertilized columns were used four blades of water, equivalent to 50, 100, 150 and 200% of the water layer obtained by the mass difference of the columns of the treatments 100%. The irrigations were applied every three days for a period of 81 days. The losses of NO3- and K+ in the columns were quantified. Joint analysis of data was performed according to the time factor. The second experiment was conducted in 2014 in Oxisol Red Dystrophic clayey, in Urutaí, Goiás, Brazil. Four irrigation levels were applied, the equivalent to 50, 100, 150 and 200% of crop evapotranspiration (ETc), estimated by the method of Class A tank. The plots were arranged in a randomized complete block design with four replications, and seven evaluations of soil solution throughout the experiment. As K+ source was used the potassium chloride with 58% K2O and as N source was used calcium nitrate with 15.5% of N. To collect soil solution, extractors of solution were installed at depths of 0.20, 0.40, 0.60, 0.80 and 1.00 m, and certain of the extracted solution, the concentrations of NO3- and K+. In crop harvest were evaluated the production components and productivity of beans. With the first experiment it is concluded that the movements of N-NO3- and K+ varied depending on the soil and irrigation levels, being that, the higher the applied water blade, the greater the amount of leached ions NO3- and K+. With the second experiment it is concluded that the movements of NO3- and K+ in the soil profile varied between the treatments, showing increased losses, below the roots, due to the application of greater irrigation blade, and that the correct irrigation management in the bean (100% the ETc), combined with appropriate doses and periods of nitrogen and potassium applications provide the best yield of grains / A crescente demanda mundial por alimentos e a diminuição na abertura de novas áreas para expansão, devido à pressão pela preservação ambiental, vem intensificando o processo de verticalização da produção agrícola, resultando na mudança do padrão extensivo para o padrão intensivo. Na região do Cerrado, tradicionalmente com solos de baixa fertilidade e ciclo hidrológico bem definido, observa-se que este processo de intensificação, tem se caracterizado por aplicação de grandes quantidades de fertilizantes e irrigação. Entretanto, o manejo incorreto da irrigação e das doses e épocas de aplicação de nutrientes, principalmente os de alta mobilidade no solo, podem causar perdas por lixiviação, resultando em prejuízos tanto econômicos quanto ambientais. Assim, o objetivo desta tese foi quantificar as perdas de nitrato (NO3-) e potássio (K+), sob diferentes manejos de irrigação, em solos arenoso e argiloso em ambiente protegido, e a campo, os efeitos na cultura do feijoeiro irrigado por aspersão em solo argiloso. O primeiro experimento foi conduzido em 2014, em Urutaí, Goiás. As colunas de solo indeformado foram arranjadas em blocos completos casualizados com três repetições. Como fonte de nitrogênio utilizou-se o nitrato de cálcio com 15,5% de Nitrogênio Total (N) e como fonte de K+ utilizou-se o cloreto de potássio com 58% de K2O. Nas colunas adubadas foram aplicadas quatro lâminas de água, equivalentes a 50, 100, 150 e 200% da lâmina de água obtida pela diferença de massa das colunas dos tratamentos 100%. As irrigações foram realizadas a cada três dias, por um período de 81 dias. As perdas de NO3- e K+ nas colunas foram quantificadas. Foi realizada análise conjunta dos dados de acordo com o fator tempo. O segundo experimento foi conduzido em 2014, num Latossolo Vermelho Distrófico de textura argilosa, em Urutaí, Goiás. Foram aplicadas quatro lâminas de irrigação, equivalentes a 50, 100, 150 e 200% da evapotranspiração da cultura (ETc), estimadas pelo método do tanque Classe A. As parcelas foram arranjadas em blocos completos casualizados com quatro repetições, sendo sete avaliações da solução do solo ao longo do experimento. Como fonte de K+ utilizou-se o cloreto de potássio com 58% de K2O e como fonte de N utilizou-se o nitrato de cálcio com 15,5% de N. Para coleta da solução do solo foram instalados extratores de solução nas profundidades de: 0,20, 0,40, 0,60, 0,80 e 1,00 m, sendo determinadas da solução extraída, as concentrações de NO3- e K+. Na colheita da cultura avaliaram-se os componentes de produção e a produtividade dos grãos de feijão. Do primeiro experimento concluiu-se que as movimentações de N-NO3- e K+ variaram em função do solo e das lâminas de irrigação, sendo que, quanto maior a lâmina de água aplicada, maiores as quantidades lixiviadas dos íons NO3- e K+. Do segundo experimento concluiu-se que as movimentações de NO3- e K+ no perfil do solo variaram entre os tratamentos, evidenciando perdas cada vez maiores, abaixo das raízes, em função da aplicação de maiores lâminas de irrigação, e que o manejo correto da irrigação no feijoeiro (100% da ETc), combinado com doses e épocas adequadas de aplicações de nitrogênio e potássio, proporcionam o melhor rendimento de grãos da cultura.

O aminociclopiraclor é o primeiro herbicida sintetizado do grupo químico ácido pirimidinocarboxílico, pertence à classe das auxinas sintéticas, atua em um amplo espectro de plantas daninhas, e está em fase de registro junto a ANVISA. A literatura sobre o aminociclopiraclor ainda é limitada, mas sabe-se que suas principais vantagens são o amplo espectro de controle de plantas daninhas, elevada eficácia em baixas doses de aplicação, e baixa toxicidade a organismos não alvo. Estudos como degradação, sorção - dessorção e lixiviação de herbicidas em diferentes tipos de solos são indispensáveis para revelar a dinâmica do seu comportamento no solo promovendo subsídios para evitar efeitos prejudiciais ao ambiente e as culturas subsequentes. O presente trabalho teve como objetivo a avaliação da dinâmica do herbicida aminociclopiraclor através de ensaios de degradação e mineralização, sorção-dessorção e lixiviação em três solos brasileiros: Latossolo Vermelho distrófico (LVd - textura arenosa), Plintossolo Pétrico concrecionário (FFc - textura argilosa) e Latossolo Vermelho eutrófico (LVe - textura muito argilosa). Os estudos foram realizados no Laboratório de Ecotoxicologia do CENA/USP seguindo as normas da \"Organisation For Economic Co-operation and Development\" (OECD). As taxas de mineralização do aminociclopiraclor nos solos avaliados foram inferiores a 10%, e seguem a seguinte ordem: FFc < LVd < LVe. A concentração extraível do aminociclopiraclor foi reduzida em 37% após 126 dias, indicando a tendência à formação de resíduos ligados. O sistema de eluição utilizado na técnica de cromatografia em camada delgada não foi adequado para separar e qualificar a presença de metabólitos extraíveis. O modelo de Freundlich apresentou ajuste adequado para a sorção e dessorção do aminociclopiraclor, com coeficientes de correlação superiores a 0,99 para os três solos avaliados. Os coeficientes de sorção variaram entre 0,37 e 1,34 enquanto os de dessorção variaram entre 3,62 a 5,36. Os coeficientes de sorção apresentam correlação positiva significativa com os teores de argila, o mesmo comportamento não foi verificado em relação ao pH. Nos solos de textura argilosa (FFc e LVe), o aminociclopiraclor apresentou médias de lixiviação inferiores a 1%, e no solo de textura arenosa (LVd) superior a 3%. As concentrações do herbicida na primeira camada do solo (0-5 cm) apresentaram correlação positiva significativa com os teores de argila e capacidade de troca catiônica, o mesmo não foi observado em relação a matéria orgânica / The aminocyclopyrachlor is the first herbicide of the chemical group pyrimidinecarboxylic acid, belongs to the class of synthetic auxin, acts in a broad spectrum of weeds and is under registration at ANVISA. The literature on the aminocyclopyrachlor is still limited, but it is known that its main advantages are the broad spectrum of weed control, high efficacy at low application rates, and low toxicity to non-target organisms. Studies such as degradation, sorption-desorption and leaching of herbicides in different types of soils are essential to reveal the dynamics of its behavior in the soil promoting subsidies to avoid adverse environmental effects and the subsequent cultures. This study aimed to evaluate the dynamics of herbicide aminociclopiraclor by testing degradation and mineralization, sorption-desorption and leaching in three Brazilian soils: Latossolo Vermelho distrofico (LVd - sandy texture), Plintossolo Petrico concrecionãrio (FFc - clay texture) and Latossolo Vermelho eutrofico (LVe - clay texture). The studies were conducted at the Laboratory of Ecotoxicology CENA/USP, following the rules of the Organisation For Economic Co-operation and Development (OECD). Mineralization rates in the aminocyclopyrachlor evaluated soils were lower than 10%, and follow the following order: FFc <LVd <LVe. The concentration of extractable aminocyclopyrachlor was reduced by 37% after 126 days, indicating the tendency to formation of bound residues. The system elution technique used in thin layer chromatography was inadequate to separate and qualify the presence of extractable metabolites. The Freundlich model showed an adequate fit for the sorption and desorption of aminocyclopyrachlor, with correlation coefficients higher than 0.99 for the three test soils. The sorption coefficients ranged from 0.37 to 1.34 while the desorption ranged from 3.62 to 5.36. The sorption coefficients showed a significant positive correlation with the clay, the same behavior was not observed in relation to pH. In clay soils (FFc and LVe), the aminocyclopyrachlor presented averages less than 1% leaching, and sandy soil (LVd) exceeding 3%. The concentrations of the herbicide in the topsoil (0-5 cm) showed significant positive correlation with clay content and cation exchange capacity, the same was not observed for organic matter

A doença vassoura-de-bruxa reduziu expressivamente a produtividade dos cacauais da região sul da Bahia, maior produtora nacional. O controle genético da enfermidade, com o uso de plantas tolerantes e com alto potencial produtivo, tem sido a principal estratégia para o convívio com essa doença. O plantio de mudas clonais, provenientes de estacas enraizadas, tem mostrado ser uma prática promissora para a renovação da lavoura. O Instituto Biofábrica de Cacau (IBC), criado em 1999, tem como um de seus objetivos produzir e comercializar essas mudas. Estudos preliminares mostraram a necessidade de aprimoramento do protocolo, pois foram observados distúrbios nutricionais, apesar do uso elevado de fertilizantes. Os objetivos deste trabalho foram: avaliar a perda de nutrientes; comparar metodologias de extração de nutrientes em substratos; identificar a folha mais adequada para ser utilizada como diagnóstica; comparar formas de adubação; definir níveis críticos (NC) e doses recomendáveis de P e de N. Foram realizados dois experimentos, ambos em viveiro de produção de mudas do IBC, onde se utilizou o clone PH 16, com 12 mudas por parcela útil (uma muda por tubete de 288 cm3), sendo avaliados: diâmetro, altura, área foliar, matéria seca, concentração e conteúdo de nutrientes na planta. O primeiro experimento, implantado em julho de 2005, foi um fatorial 5x5+1: cinco substratos (misturas de fibra de coco &#150; FC e Plantmax&#174;), cinco doses de P no plantio (de zero a 0,8 g dm-3) e um tratamento adicional (P aplicado aos 30 dias); o segundo experimento, instalado em julho de 2006, foi um fatorial 2x5: duas formas de adubação, no substrato e foliar, e cinco doses de uréia, aplicadas semanalmente após o 82º dia. A análise do lixiviado do primeiro experimento identificou variações do pH, da condutividade elétrica e dos nutrientes de acordo com os tratamentos e com o tempo. A terceira folha do primeiro lançamento maduro foi a mais indicada para ser utilizada como folha diagnóstica. Para a maioria dos nutrientes, não foram encontradas correlações significativas entre os teores extraídos dos substratos, por metodologias distintas, com os absorvidos pelas plantas, exceto para P, K, Ca e Cu. A adubação com P em cobertura aumentou sua disponibilidade e absorção, mas não afetou o crescimento das mudas. Os melhores substratos foram os que continham entre 30 a 55% de FC. As doses recomendáveis, calculadas para obtenção de 99% da produção máxima da matéria seca da parte aérea, variaram de 136 a 275 g m-3 de P, aplicadas em préestaqueamento, de acordo com o substrato; e, para N, em aplicação semanal pósenraizamento, foi de 63 mg dm-3 para a adubação no substrato ou de 11,7 g L-1 para a adubação foliar. Para o N, a adubação no substrato foi superior à foliar. O NC de P no substrato variou de acordo com o extrator e o substrato e os NCs foliares foram de: 1,75 g kg-1 de P e 23,1 g kg-1 de N. / The witches&#39; broom disease decreased expressively the cocoa productivity in Bahia south region, the biggest national producer. The disease genetic control, using tolerant plants with high potential productivity, has been the main strategy to cope with this disease. The cloned cutting breeding, originated from rooted cuttings, has proved to be a promising practice for crop renovation. The &#34;Instituto Biofábrica de Cacau&#34; (IBC) or Cocoa Biofactory Institute, founded in 1999, has one of its aims to produce and commercialize these rooted cuttings. Preliminary studies have shown the need of protocol improvement, as it was observed nutritional problems, despite the high use of fertilizers. The objectives of this work were: Evaluate nutrients losses; compare nutrient extraction methodologies in potting mix; identify the most suitable leaf to be used as diagnostic; compare different fertilization practice; define P and N critical levels (CL) and recommendable doses. It was carried out two experiments, both in cloning breeding nurseries of IBC, where it was used clone PH 16, with 12 cuttings by useful plot (one cutting by container of 288 cm3), being evaluated: diameter, height, foliar area, dry matter, concentration and nutrient content in plants. The first trial, implanted in July 2005, was a factorial 5x5+1: five potting mix (mix of coconut fiber &#150; CF and Plantmax&#174;) five doses of P in the planting (from 0 to 0.8 g dm-3) and an additional treatment (P applied on the 30th day); the second experiment, installed in July 2006, there was a factorial 2x5: two fertilization treatments, in potting mix and foliar, and five urea doses, applied weekly after the 82nd day. The first experiment leaching analysis identified variations of the pH, electric conductivity and nutrients according to treatments and time. The third leaf from first ripen sprout was the most indicated to be used as the diagnostic leaf. For most nutrients were not found significant correlation between substrate extract levels by distinct methodologies and the absorbed ones by plants, except for P, K, Ca and Cu. The P fertilization in covering increased its availability and absorption, but did not affect cutting growth. The best substrates were those contained between 30 and 55% of CF. The recommendable doses, assessed to obtain 99% of the maximum production of shoot dry matter, varied from 136 to 275 g m-3 of P, applied in the precutting, according to the substrate; and for N, in weekly pos-rooting application, was 63 mg dm-3 for the substrate fertilization or 11.7 g L-1 for foliar fertilization. For the N, the substrate fertilization was superior to foliar. The CL of P in the potting mix varied according to extractor and substrate and the foliar CLs were: 1.75 g kg-1 of P and 23.1 g kg-1 of N.

This report describes a 3 year study carried out to determine the effects of modern coal power generation technologies on the properties of fly ash and how these may affect the use of the material in concrete. A total of 18 fly ashes, from 11 different sources, produced under a range of conditions and technologies were investigated. These primarily included co-combustion, low NOx, supercritical and oxy-fuel technologies, although other available materials (run-of-station, air-classified, processed and stockpiled fly ashes) were included for comparison. The initial experimental work involved physical and chemical characterization of the fly ash samples. Thereafter, tests covering fresh properties, strength development and durability were carried out on selected concretes. A fly ash level of 30% was used with w/c ratios covering the practical range considered (0.35 to 0.65). Equal strength comparisons were also made where appropriate. Finally, granular (unbound fly ash) and monolithic (fly ash concrete) leaching tests were carried out to assess the environmental implications of using the fly ashes. The results from the physical and chemical characterization tests suggest that modern technologies used for coal fired power generation can have an influence on the properties of fly ash produced. The co-combustion, oxy-fuel and in-combustion low NOx fly ashes had reduced fineness and greater LOI, which had a negative effect on foam index and water requirement of the materials. However reactivity was largely unaffected. The post-combustion low NOx and supercritical fly ashes appeared to be unaffected by their production methods compared to that produced by conventional/establish means. Tests on fresh concrete properties showed that fly ashes with high LOI and low fineness required higher SP doses than the reference PC concrete. However, fly ashes with high fineness and low surface area were found to require a lower SP dose than the PC concrete. The concrete compressive strength tests indicate that, in general, finer fly ash concretes tended to have higher strengths than those containing coarser material. However, there did not appear to be any significant difference in performance between fly ash concretes, which suggests that, although modern technologies can have an impact on fly ash properties, if account is taken of these they should not have any significant influence on strength development. Comparison with an earlier study from the 1990s considering BS EN 450-1 fly ashes showed general agreement between the data. The durability study showed that finer, low LOI fly ashes had higher chloride resistance and at equal strength fly ash concretes performed better than those with PC. Equal strength fly ash concretes covering the modern technologies were found to have similar levels of durability for sulfate attack, abrasion and carbonation. High alkali concrete (following the BS 812-123 method) gave similar expansion levels and good resistance with respect to AAR. With air-entrainment, it was found that the fly ash concretes required high doses of AEA (relative to the PC concrete), with high LOI/BET fly ashes requiring greatest quantities. At equal strength, the fly ash concretes had poorer freeze-thaw scaling resistance than PC concrete. However, the majority of the fly ashes did manage to achieve acceptable scaling resistance according to the Swedish criteria. In general, the findings of the durability study are in agreement with the earlier study from the 1990s. Overall, no effect of production technology on the durability of concrete was observed. The leaching studies showed that, in general, in both granular and concrete form, modern fly ashes met the non-hazardous waste requirements in the WAC for all components tested except chromium. For the granular test, there were instances where elevated chromium levels were observed. Similarly, the fly ash concretes failed to meet the non-hazardous limit for chromium. However, chromium from the cement may have contributed to this, since the PC reference also failed to meet this requirement. Based on the results, there is no effect of production technology on the leaching characteristics of fly ash or concrete and the materials do not appear to pose a significant environmental risk. The practical implications of the study have been considered and overall, it has been shown that modern fly ashes behave in much the same way as traditional materials, and therefore, if these materials meet the requirements of BS EN 450-1, and their properties are taken into account in the proportioning of concrete, they should give satisfactory performance.