Made available in DSpace on 2014-06-11T19:22:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-09Bitstream added on 2014-06-13T19:27:19Z : No. of bitstreams: 1 deus_acf_me_botfca.pdf: 1380017 bytes, checksum: 6e4d5e1437947fadf9a4d182d77580da (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A eficiência dos corretivos de acidez do solo, e, sua qualidade depende da taxa de reatividade (RE), e do poder de neutralização (PN), sendo esta eficiência indicada pelo poder relativo de neutralização total (PRNT). Para os silicatos existem poucos estudos que estabeleça taxas de reatividade para suas frações granulométricas e, portanto, utilizam-se as mesmas taxas de reatividade do calcário. Foram desenvolvidos três experimentos no período de julho/2008 a outubro/2009 em casa de vegetação na Faculdade de Ciências Agronômicas/UNESP – Botucatu-SP, com o objetivo de comparar valores de reatividade das frações granulométricas para materiais silicatados em três solos de diferentes classes texturais cultivados com plantas de alfafa. Utilizou-se seis materiais corretivos: escória, silicato de cálcio, silicato de cálcio e magnésio, wollastonita, calcário dolomítico e calcário calcítico os quais no experimento 1 e 2 foram separados em quatro frações granulométricas, peneiras: nº 10 (Ø = 2 mm), nº 20 (Ø = 0,84 mm), nº 50 (Ø = 0,30 mm) e fundo (Ø<0,30 mm), exceto a wollastonita que possui apenas a granulometria < 0,30 mm. Os tratamentos foram aplicados em três solos: Latossolo Vermelho distrófico, Nitossolo Vermelho eutrófico e Neossolo Quartzarênico. No 1° experimento aplicou-se quatro doses (1, 2, 4 e 8 t ha-1) afim de obter a curva de neutralização dos solos, para determinar a dose a ser aplicada de cada fração granulométrica para atingir o pH 5,5. O 2° experimento constou da aplicação das doses ecomendadas no primeiro experimento e com o valor de pH obtido aos 90 dias de incubação calculou-se a eficiência relativa de reatividade para cada fração granulométrica, tomando-se como referência o pH obtido com a aplicação do calcário dolomítico na peneira... / The efficiency and quality of materials for soil acidity correction are based on the reactivity rate (RR) and neutralization power (NP), and it is indicated by the effective calcium carbonate (ECC). Considering that there are few studies establishing reactivity rates of silicate particle-size fractions, lime values are used as reference. Three experiments were carried in the period July/2008 to October/2009 out in greenhouse in College of Agricultural Sciences, UNESP, Botucatu – SP, aiming to compare reactivity rates of silicate particle-size fractions in three soils with distinct textures cultivated with alfalfa plants. Slag, calcium silicate, calcium+magnesium silicate, wollastonite, dolomitic and calcitic lime were the materials evaluated. The first and second experiments consisted of four particlesize fractions obtained from each material, separated by the sieves no. 10 (Ø = 2 mm), no. 20 (Ø = 0.84 mm), no. 50 (Ø = 0.30 mm) and bottom (Ø < 0.30 mm), except that the wollastonite has the particle-size fraction < 0,30 mm. Treatments were applied in three soils: Oxisol, Hapludox and Quartzipsamment. In the first study, four doses were applied (1, 2, 4 and 8 t ha- 1) to obtain soil neutralization curve and thus determine which one was to be applied for each particle-size fraction to reach pH 5.5. The second study consisted of the application of the recommended doses from the first experiment. Then, with the pH values obtained 90 days after incubation, the relative efficiency of reactivity was calculated for each particle-size fraction based on the pH of dolomitic lime from the last sieve. Afterwards, RR and ECC were calculated. In the third study, the doses to increase soil base saturation up to 80% were calculated based on both the PRNT reported in the laboratory and in the experiment. Treatments were incubated... (Complete abstract click electronic access below)

Orientador: Carlos Alexandre Costa Crusciol / Banca: José Salvador Simoneti Foloni / Banca: Eduardo Fávero Caires / Resumo: No sistema plantio direto praticamente não há revolvimento do solo e o consequente acúmulo de fertilizantes na superfície acelera o processo de acidificação, contínuo e acentuado que ocorre naturalmente em solos de regiões úmidas, onde, geralmente, é observada baixa disponibilidade de nutrientes e elevados teores de alumínio. Assim, da mesma forma que no sistema de cultivo convencional, no sistema plantio direto também existe a necessidade de aplicação de insumos em superfície, especialmente, materiais corretivos de acidez. Dentro deste enfoque, o trabalho foi desenvolvido na Fazenda Experimental Lageado, pertencente à Faculdade de Ciências Agronômicas - UNESP, Campus de Botucatu (SP), dando continuidade a um projeto de pesquisa que vem sendo conduzido desde 2002, com o objetivo de avaliar o efeito residual da aplicação superficial de corretivos na correção da acidez do solo, bem como na nutrição, na produtividade das culturas da soja e do sorgo e na produção de matéria seca e acúmulo de nutrientes da aveia-preta em região de inverno seco. O delineamento experimental utilizado foi em blocos casualizados em parcelas subdivididas, com 4 repetições. As parcelas foram constituídas por quatro doses de calcário (0, 1000, 2000 e 4000 kg ha-1) e as subparcelas por duas doses de gesso agrícola (0 e 2100 kg ha-1), aplicado em novembro 2004. Como cultura de verão foi utilizada a cultura da soja e na entressafra as culturas da aveia-preta e sorgo granífero. A aplicação de calcário em superfície promoveu diminuição da acidez e elevação nos teores de fósforo, cálcio, magnésio e matéria orgânica, em praticamente todo perfil do solo. A aplicação de gesso agrícola promoveu aumentos nos 2 teores de Ca trocável e S-SO42-, e diminuição no teor de Al trocável no solo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In no tillage system the absence of soil mobilization consequently decreases places fertilizers on surface, affecting the acidification process. Like in conventional system, in no tillage it is also necessary input application, especially materials for acidity correction. The experiment was carried out in an experimental area, in the city of Botucatu (SP, Brazil), continuing a research project that has been conducted since 2002, to evaluate the long-term effects of surface application of lime and gypsum on acidity correction, nutrition, yield of soybean and sorghum, and dry matter production and nutrients accumulation on black oat in a dry winter region. The experimental design was the completely randomized with subdivided plots and four replications. The mains plots consisted of four dolomite limestone levels (0, 1000, 2000 e 4000 kg ha-1) and the subplots consisted areas with and without gypsum (0 and 2100 kg ha-1), applied in November 2004. Soybean was the summer crops and the off-season crops are black oat and grain sorghum Lime surface application reduced soil acidity and increased phosphorus, calcium, magnesium and organic matter, practically all the soil profile. Phosphogypsum application promoted increasing exchangeable Ca and S-SO42- contents, and decreased exchangeable Al in the soil, favoring the effects of surface liming on soil properties, mainly the surface layer (0-0.20 m). Base saturation values obtained at a depth of 0-0.20 m with liming were lower than those estimated by BS method, even with phosphogypsum application. Liming increased, on soybeans, foliar contents of N, P, Ca, Mg and S in 2008/09, and N, Ca and Mg, in 2009/10. In the presence of phosphogypsum increased the levels of N In no tillage system the absence of soil mobilization consequently... (Complete abstract click electronic access below) / Mestre

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Dois estudos consecutivos foram realizados para reavaliar a faixa ideal de pH e a tolerÃncia de juvenis de tilÃpia do Nilo, Oreochromis niloticus, à acidez elevada da Ãgua de cultivo, em condiÃÃes eutrÃficas de cultivo. Os pesos iniciais dos animais eram semelhantes em ambas as fases. No primeiro trabalho, foram adotadas quatro condiÃÃes distintas de pH da Ãgua de cultivo: pH = 5,56  1,21 (pH 5); pH = 6,59  0,77 (pH 6); pH = 8,25  0,39 (pH 8); pH = 9,21  0,37 (pH 9), obtidas pelas aplicaÃÃes de soluÃÃes Ãcidas ou alcalinas à Ãgua. Os animais foram mantidos em tanques externos de 250 L por oito semanas. NÃo houve renovaÃÃo da Ãgua de cultivo ao longo de todo o trabalho. Neste trabalho, foram observadas variÃveis de qualidade de Ãgua, solo, zootÃcnicas e metabÃlicas. As maiores concentraÃÃes de nitrogÃnio amoniacal total da Ãgua foram encontradas nos tanques pH 5 e as menores nos tanques pH 8. A concentraÃÃo de gÃs sulfÃdrico na Ãgua foi maior nos tanques pH 5. O peso corporal final, a taxa de crescimento especÃfico e a produtividade do pescado nos tanques pH 5 foram maiores do que o observado nos tanques pH 9. Observou-se maior consumo de oxigÃnio nos respirÃmetros de pH 9. Concluiu-se que a faixa ideal de pH da Ãgua para o cultivo de juvenis de tilÃpia do Nilo, em Ãguas eutrofizadas, vai de 5 a 8. O delineamento experimental do segundo trabalho foi constituÃdo por quatro tratamentos, a saber: Ãguas de cultivo com diferentes valores de pH (pH 4: 4,12  0,84; pH 5: 5,13  0,74; pH 6: 6,14  0,64 e pH 8: 8,06  0,48), com cinco repetiÃÃes cada. NÃo houve troca da Ãgua de cultivo, apenas reposiÃÃo para manter o nÃvel inicial. Durante oito semanas, foram observadas variÃveis de qualidade de Ãgua, solo, zootÃcnicas, metabÃlicas e qualidade de efluentes. Embora a concentraÃÃo de nitrogÃnio amoniacal total (NAT) na Ãgua tenha sido menor nos tanques pH 8, sua concentraÃÃo de amÃnia nÃo-ionizada (NH3) foi maior que nos demais. Ao final, o menor peso corporal dos peixes foi observado nos tanques pH 8. Houve significativa melhora nos resultados de conversÃo alimentar e na taxa de eficiÃncia proteica com a acidificaÃÃo da Ãgua. As concentraÃÃes de NH3 nos efluentes dos tanques acidificados foram reduzidas. Concluiu-se que a acidificaÃÃo gradual da Ãgua de cultivo de juvenis da tilÃpia do Nilo atà pH 4 à benÃfica ao crescimento corporal dos peixes. A avaliaÃÃo de todos os resultados permite inferir que a faixa de pH da Ãgua para cultivo de O. niloticus seja de 4 a 8. / The first experiment aimed to reassess the Nile tilapiaâs optimum range of water pH for culture in eutrophic conditions. The initial weights of the animals were similar in both phases. There were four different conditions of water pH: pH = 5,56  1,21 (pH 5); pH = 6,59  0,77 (pH 6); pH = 8,25  0,39 (pH 8); pH = 9,21  0,37 (pH 9), that were obtained by acidic or alkaline applications upon the rearing waters. The fishes were maintained in twenty outdoor 250-L tanks for eight weeks. No water exchange was performed over the entire study. Variables of water and soil quality, growth performance and metabolism were monitored in the 1st work. The highest concentration of total ammonia nitrogen was observed in the pH 5 tanks and the lowest ones in the pH 8 ones. The hydrogen sulfide concentrations were higher in the pH 5 tanks. Fish final body weight, specific growth rate and yield were higher in the pH 5 tanks than in the pH 9 ones. There was a higher consumption of dissolved oxygen in the pH 9 respirometers than in the other ones. It was concluded that the optimum water pH range for Nile tilapia culture in eutrophic waters is 5 â 8. The second experiment aimed to determine the tolerance of Nile tilapia juveniles to high acidic culture waters and the effects of the culture water acidification upon the tanksâ effluents quality. The experimental design had four treatments, e.g., waters with different pH values (pH 4: 4,12  0,84; pH 5: 5,13  0,74; pH 6: 6,14  0,64 e pH 8: 8,06  0,48), with five replicates each. No water exchange was carried out over the entire study, just water replenishment to maintain the initial level. Variables of water quality, soil, growth performance, metabolism and effluents were observed over eight weeks. In spite of the lower total ammonia nitrogen (TAN) concentration in the pH 8 tanks, their levels of non-ionized ammonia (NH3) were the highest. At the end, the lowest fish body weight was observed in the pH 8 tanks. There was a significant improvement in the feeding conversion ratio and protein efficiency rate by the water acidification. The concentrations of NH3 were reduced in the acidic tank effluents. It was concluded that the gradual water acidification up to pH 4 is good to Nile tilapia juvenilesâ growth performance. The evaluation of all the results shows that the water pH range for cultivation of O. niloticus is 4-8.

Made available in DSpace on 2017-07-10T17:37:24Z (GMT). No. of bitstreams: 1 Leandro-Rampim.pdf: 366762 bytes, checksum: 5aa4ca621ef50368e9c462be07112b71 (MD5) Previous issue date: 2008-03-23 / Fundação Araucária / The presence of aluminum in the soil is one among the several existent problems that harm the growth, development and productivity in commercial cultures as soy and wheat principally when water deficit, once there is minor surface of roots for the absorption of water. Like this the influence of the use of the plaster was analyzed in the chemical characteristics of a Latossolo vermelho eutroférrico of loamy texture for the wheat cultures and soy, under system of direct planting. It took place collections of soil samples to the six and 12 months after application 0, 1, 2, 3, 4 e 5 t ha-1 of the gypsum to evaluate the tenors of Ca, Mg, K, exchangeable Al, pH, SB, V%, m% and tenor of S in the soil. For the wheat cultures and soy they were appraised the tenors of Ca, Mg, K, S, and Al in the tissue, mass of 1000 grains and productivity. The use of gypsum increased the tenors of Ca and S and it reduced Al's tenors, besides leaching Mg and K in the soil, increasing SB and V% in the deepest layers. In the tissue increased Ca and Mg for the soy and it reduced in the wheat, it increased the tenor of S in both cultures and K increased in a quadratic way for the culture of the soy. The found results show that the use of the plaster provided mobility of K+ and Mg2+ up to 40 cm of depth. The use of up to 5 t ha-1 of gypsum they resulted in increase of the tenors of Ca2+ and SO42 - in depth until one year after the application and the dose of 3 t ha-1 it provided larger reduction of exchangeable Al and also of the saturation for Al for Latossolo vermelho eutroférrico of loamy texture. In exchangeable Al's presence the use of the gypsum implicated in increase of the wheat productivity but it didn't influence the productivity of the soy / A presença de alumínio no solo é um entre os diversos fatores existentes que prejudicam o crescimento, desenvolvimento e produtividade de culturas comerciais como soja e trigo principalmente quando ocorre déficit hídrico, uma vez que há menor superfície de raízes para a absorção de água e nutrientes. Este trabalho avaliou a influência do uso do gesso nas características químicas de um Latossolo Vermelho eutroférrico de textura argilosa para as culturas de trigo e soja, sob sistema de plantio direto. Realizou-se coletas de amostras de solo aos seis e 12 meses após aplicação superficial de 0, 1, 2, 3, 4 e t ha-1 de gesso para avaliar os teores de Ca, Mg, K, Al trocáveis, pH, SB, V%, m% e teor de S no solo. Para as culturas de trigo e soja foram avaliados os teores de Ca, Mg, K, S, e Al no tecido foliar, massa de 1000 grãos e produtividade. O uso de gesso aumentou os teores de Ca e S e reduziu os teores de Al, além de lixiviar Mg e K no solo, aumentando a SB e V% nas camadas mais profundas. No tecido foliar aumentou Ca e Mg para a soja e reduziu no trigo, aumentou o teor de S em ambas culturas e o K aumentou de forma quadrática para a cultura da soja. Os resultados encontrados mostram que o uso do gesso proporcionou mobilidade de K+ e Mg2+ até 40 cm de profundidade. O uso de até 5000 kg ha-1 de gesso resultaram em aumento dos teores de Ca2+ e SO42- em profundidade até um ano após a aplicação sendo que a dose de 3 t ha-1 proporcionou maior redução do Al trocável e também da saturação por Al para o Latossolo Vermelho eutroférrico de textura argilosa. Na presença de Al trocável o uso do gesso implicou em aumento da produtividade de trigo mas não influenciou a produtividade da soja

Made available in DSpace on 2017-07-10T17:37:53Z (GMT). No. of bitstreams: 1 Tatiane_Ohland.PDF: 1598453 bytes, checksum: ed82eeb6e587304b7aaf365f98d333aa (MD5) Previous issue date: 2012-07-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Two experiments were conducted in a greenhouse in pots made of PVC tubes containing 10.6 dm3 of soil, using a randomized complete block design with four replications. The first experiment aimed to evaluate the influence of soil density in the initial development of physic nut (Jatropha curcas L.). The soil used was an Oxisol clayey, in levels of bulk density of 1.08, 1.22, 1.36, 1.50 and 1.64 kg dm-3. After 120 days of plant emergence, was evaluated the number of leaves, plant height, stem diameter, leaf area, root length, root volume, dry matter of leaves + petioles, stems, roots, total dry matter of plant, root/shoot ratio and the content of P, K, Ca and Mg. The results indicate that the increase of soil density negatively affected the development of shoot and root system of plants of physic nut. The limitation of shoot growth occurred from the estimated density of 1.26 kg dm-3, reducing the number of leaves, leaf area and dry matter of shoots. The root system development and content of P and K in plants of physic nut decreased linearly with increasing density. The contents of Ca and Mg is not influenced by increasing the density of the soil. The second experiment aimed to evaluate the initial development of physic nut in different limestone rates in subsurface. The soil used was Oxisol clayey collected in Cascavel - PR. The physic nut plants were grown in PVC pots divided into two rings, the upper ring (0-20) received limed soil (11.1 t ha-1 of CaCO3 and MgCO3) and fertilized, the lower ring (20-60 cm) was added to soil at doses of 0, 3.7, 5.6, 7.4, 11.1 and 14.9 t ha-1 of CaCO3 and MgCO3 in 4:1 molar ratio. After 120 days of plant emergence, was evaluated the number of leaves, leaf area, plant height, stem diameter, root length, root volume, dry matter of leaves, stems, roots, and total dry matter of plant and levels of Al, P, K, Ca, Mg, Zn, Cu, Mn and Fe in leaves, stems and roots. The development of the shoot of physic nut was not limited by the different limestone rates in subsurface, as assessed by plant height, stem diameter, dry matter of leaves, stem and total dry matter of plant. The decrease in limestone rates reduces the volume and dry matters of roots in subsurface. Liming decreased the concentration of Zn and Mn in shoots and roots, which may have influenced the plant height and root volume / Foram conduzidos dois experimentos em casa de vegetação, em vasos constituídos por tubos de PVC contendo 10,6 dm-3 de solo, utilizando o delineamento experimental em blocos casualizados, com quatro repetições. O primeiro experimento teve como objetivo avaliar a influência da densidade do solo no desenvolvimento inicial da cultura do pinhão-manso (Jatropha curcas L.). O solo utilizado foi o Latossolo Vermelho eutroférrico de textura argilosa, sob os níveis de densidade do solo de 1,08; 1,22; 1,36; 1,50 e 1,64 kg dm-3. Após 120 dias da emergência das plantas, avaliou-se o número de folhas, altura de planta, diâmetro de caule, área foliar, comprimento da raiz principal, volume radicular, produção de matéria seca de folhas+pecíolos, caule, raízes, planta inteira, relação raiz/parte aérea e o conteúdo de P, K, Ca e Mg. Os resultados indicam que o aumento da densidade do solo afetou negativamente o desenvolvimento da parte aérea e do sistema radicular de plantas de pinhão-manso. A limitação do desenvolvimento da parte aérea ocorreu a partir da densidade estimada de 1,26 kg dm-3, com redução do número de folhas, área foliar e produção de matéria seca da parte aérea. O desenvolvimento do sistema radicular e o conteúdo de P e K nas plantas de pinhão-manso reduziram linearmente com o aumento da densidade do solo. O conteúdo de Ca e Mg não foi influenciado pelo aumento da densidade do solo. O segundo experimento teve como objetivo avaliar o desenvolvimento inicial do pinhão-manso sob diferentes doses de calcário em subsuperfície. O solo utilizado foi o Latossolo Vermelho distroférrico de textura argilosa coletado em Cascavel - PR. As plantas de pinhão-manso foram cultivadas em vasos de PVC dividido em dois anéis, o anel superior (0-20 cm) recebeu solo corrigido (11,1 t ha-1 de calcário) e adubação com NPK, no anel inferior (20-60 cm) foi adicionado o solo com as doses de 0; 3,7; 5,6; 7,4; 11,1 e 14,9 t ha-1 de CaCO3 e MgCO3 na relação molar 4:1. Após 120 dias da emergência das plantas, avaliou-se o número de folhas, área foliar, altura de planta, diâmetro de caule, comprimento da raiz, volume radicular, produção de matéria seca de folhas, caule, raízes, planta inteira e o teores de Al, P, K, Ca, Mg, Zn, Cu, Mn e Fe nas folhas, no caule e nas raízes. O desenvolvimento da parte aérea do pinhão-manso não foi limitado pelas doses de calcário aplicadas em subsuperfície, avaliado pela altura de planta, diâmetro de caule, produção de matéria seca de folhas, de caule e de matéria seca total. A redução das doses de calcário reduz o volume e a matéria seca de raízes em subsuperfície. A calagem reduziu os teores de Zn e Mn na parte aérea e raízes, o que afetou a altura de planta e volume de raízes

Orientador: Edson Lazarini / Resumo: Em um sistema plantio direto em processo de estabilização, preconiza o não revolvimento do solo. Neste sentido o uso de gesso agrícola pode ser uma alternativa para viabilizar a aplicação do calcário em superfície sem que seja necessária sua incorporação. Dessa forma, o gesso entra como um insumo complementar ao uso do calcário. Em vista do exposto, o presente trabalho objetivou estudar o comportamento do calcário e/ou gesso reaplicados em superfície, e seus reflexos nos atributos químicos do solo e nas culturas do milho e soja em sucessão. O experimento está sendo desenvolvido desde o ano de 2011 em LATOSSOLO VERMELHO distrófico de textura argilosa, desde o ano de 2011, no qual se apresenta em delineamento em blocos ao acaso, em esquema de parcelas sub-subdivididas com quatro repetições. Como tratamentos nas parcelas, foi instalado o milho em dois sistemas de cultivo, sendo eles, solteiro e consorciado com Urochloa. Para as subparcelas foram utilizadas quatro doses de calcário (0; 2000; 4000 e 6000 kg ha-1) e quatro doses de gesso (0; 1500; 3000 e 4500 kg ha-1) distribuídas ao acaso nas sub-subparcelas. As aplicações foram em superfície manualmente em cada parcela e sendo realizadas as seguintes avaliações: características agronômicas, estado nutricional e produtividade de grãos das culturas do milho e soja e os atributos químicos do solo em diferentes profundidades (0,0 – 0,10; 0,10 – 0,20 e 0,20 – 0,40 m). O efeito residual das maiores doses de calcário reaplicados em 2014... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In the process of stabilizing in a no-tillage system, the soil revolving must be minimized. In this sense the application of lime can be an alternative to enable the use of gypsum as an alternative to conditioner the subsurface soil layers in the short term, and it can be used as a complementary product to lime because of its greater solubility and mobility in the soil profile. Therefore, the aim of this experiment was to study the effect of lime and gypsum reapplied in surface and their impacts on maize crop under the sole and intercropped with soybean. The experiment is being developed in a dystrophic Red Latosol with clayey texture, since the year of 2011, and arranged in a randomized block designs, in split-split plots, with four replications. As treatments in the plots, the maize was installed in two cropping systems: sole and intercropped with Urochloa. For the subplots, were used four doses of lime (0; 2000; 4000 and 6000 kg ha-1) and four doses of gypsum (0; 1500; 3000 and 4500 kg ha-1) randomly distributed in the sub-subplots. The applications were manual and in surface in each plot, and being performed the following evaluations: agronomic characteristics, nutritional status and grains yield of maize and soybean and the chemical attributes of soil in three different depth (0,0 – 0,10; 0,10 – 0,20 e 0,20 – 0,40 m). The residual effect of the major gypsum doses reapplied in 2014 provided greater yield on the soybean sown two years after. Higher doses of gypsum reduced ... (Complete abstract click electronic access below) / Mestre

Thesis (M.Sc. Agric (Soil Science)) -- University of Limpopo, 2013 / Knowledge and management of soil pH, particularly soil acidity across spatially variable soils is important, although this is greatly ignored by farmers in the Limpopo Province of South Africa. The significance of understanding spatial variability of soil acidity is the implementation of best and site-specific management strategies because when soil acidity is poorly managed, toxicity and nutrient deficiency problems in the soil are inevitable. The objective of the study was to evaluate in-field spatial variability of soil pH, and compare the efficiency of managing soil pH through site-specific method vs. uniform lime application. The study was conducted in 3 site years (23o50’ S; 29 o40’ E and 23o59’ S and 28o52’ E) with site year I, and II adjacent to each other in the semi-arid regions of the Limpopo Province, South Africa. Soil samples were taken in four replicates within a 1 m radius from geo-referenced locations in 3 study sites to sampling depths of 0-20 cm on a regular grid of 30m using differential Global Positioning System (DGPS). Soils were analyzed for pH, and SMP buffer pH for lime recommendations. Lime requirement to achieve a soil pH of 6.5 for a 20 cm plough layer per hectare was calculated using CalciumCarbonateequivalent, efficiency factor (fineness factor), and neutralizing index of the liming materials. The spatial maps for SMP buffer pH and lime requirement maps were produced with surfer version 8.0 (Surfer Version 8, Golden Software, Golden, CO). The soil pH datasets from systematic unaligned randomly sampled soils on a 30-m grid were interpolated using inverse distance weighing (IDW) in Surfer software version 8.0 (Surfer Version 8, Golden Software, Golden, CO). Soil pH varied from strongly acidic to slightly acidic with minimum values of 4.22, 3.93, and 4.74 and maximum values of 6.11, 7.00, and 6.82 in site I, II, and II respectively. In Site I, II, and III, the areas of the field that had soil pH values of less than 6.0 were 99.43, 82.61, and 62.89% of the field. When lime was recommended for application using a conventional method of uniform lime application based on an average value derived from samples collected in the whole field, the results of the study showed a waste of lime in excess of lime recommended for individual grids. An excess amount of lime as high as 10, 30, and 7 tons/ha recommended on sites I, II and III respectively under uniform application. These recommendations were in excess on field areas that needed little or no lime applications. Again, the fields showed under applications of lime as much as 30, 35, and 13 tons/ha in site I, II, and III respectively for uniform liming applications. This under- and over recommendations of lime based on average soil pH values suggests that uniform soil acidity management strategy is not an appropriate strategy to be adopted in these fields. Again, in both of these sites as shown in the maps, the areas that required high amount of lime and those that require little or no lime are clearly defined, such that the fields can be divided into lime application zones. When a field is divided into lime application zones, management of soil acidity becomes easier because instead of applying variable rates of lime for every grid, lime rates are applied per zone. These zones could be areas in a field that require, (i) high rates of lime, (ii) low rates of lime, and (iii) areas that requires no lime at all. Agricultural fields that exhibit spatial variability of soil acidity must not be managed or treated as uniform when lime is applied in the field. Keywords: Lime requirement, Site specific management and Soil pH.

Les zéolithes sont des aluminosilicates cristallins possédant une microporosité organisée et régulière de taille moléculaire. Les zéolithes ZSM-5 sont largement employées dans l’industrie comme catalyseurs acides mais leur application commerciale requiert des objets de taille millimétrique pour leur résistance mécanique, pour diminuer la perte de charge dans les réacteurs et pour diluer l’acidité de la zéolithe, principalement par ajout de liant, peptisant... La mise en forme est l’étape clé dans le processus d’industrialisation d’un catalyseur car les additifs peuvent modifier les propriétés intrinsèques de la zéolithe après mise en forme. Les objectifs de la thèse sont donc d’identifier et de rationaliser les conséquences physico-chimiques de la mise en forme sur les propriétés des zéolithes en étudiant l’accessibilité, la concentration et la force de leurs sites acides, ainsi que de décrire la nature de l’interface zéolithe/liant. Pour cela, une approche multi-techniques a été mise en œuvre. Elle combine des mises en forme modèles, tout en faisant varier la nature du liant et de la zéolithe ZSM-5, des caractérisations texturales, spectroscopiques (infra-rouge, RMN) et de microscopies, de l’acidité (adsorption-désorption de molécules sondes suivies par analyses thermiques et spectroscopiques), et tests catalytiques modèles. La caractérisation des propriétés des zéolithes utilisées dans cette étude (de différentes tailles de cristaux et de différents rapports Si/Al) a été menée préalablement à celles des matériaux mis en forme. Les grands cristaux de zéolithes se sont révélés plus acides mais moins actifs en catalyse. Une partie des Al des petits cristaux forment des aluminols dont l’acidité est plus faible que celle des sites pontés. De plus, l’ensemble des sites pontés ne contribue pas à la réaction catalytique, seule une partie du cristal est efficace. Durant ce travail, deux types de liants ont été utilisés : l’alumine et la silice qui sont largement employées dans l’industrie. Le but a été de mettre en évidence, dans un premier temps, les effets de la mise en forme sur une zéolithe et un liant donné puis d’estimer l’impact de la nature de la zéolithe (taille de cristal et rapport Si/Al). Pour le liant de type alumine, un bouchage partiel de la microporosité est suspecté indépendamment de la taille des cristaux et du rapport Si/Al de la zéolithe. Un phénomène d’alumination de la structure de la zéolithe par création de sites pontés a été mis en évidence. Pour le liant de type silice, le paramètre critique à prendre en considération lors de la mise en forme est sa teneur en cations sodium. Le phénomène d’échange ionique a été mis en évidence, les propriétés acides et catalytiques des catalyseurs s’effondrent mais de manière réversible. Cet effet augmente quand la taille des cristaux de zéolithes diminue et quand le rapport Si/Al augmente / Zeolites are crystalline and microporous aluminosilicates with an ordered and regular structure of molecular dimension. ZSM-5 zeolites are widely used in the industry as acid catalysts but their commercial application requires millimeter-sized bodies for mechanical strength and dilution of the zeolite acidity mainly, by addition of binder, peptizer... Shaping of zeolite is the key step of the process for the industrialization of a catalyst because the additives may modify the intrinsic properties of zeolites after shaping. The aims of this PhD thesis are to identify and rationalize the physico-chemical impacts of shaping on the zeolite properties by studying the accessibility, the concentration and the strength of acid sites, as well as to describe the zeolite/binder interface. To do this, a multi-technical approach was set up. It combines model shaped materials, by varying the type of binder and ZSM-5 zeolite, textural, spectroscopic (IR, NMR) and acid characterizations, microscopy and catalytic testing. The characterization of zeolites used in this study (various crystal sizes and Si/Al ratios) was carried out prior of those of shaped materials. Large crystals have been shown more acid but less active in catalysis. Some of Al of the small crystals form aluminols whose acidity is weaker than that of bridging sites. Moreover, all the bridging sites do not contribute to the catalytic reaction, only a part of the crystal is efficient. During this work, two types of binders were used: alumina and silica which are widely used in the industry. The strategy was to highlight, in a first step, the shaping impacts on a ZSM-5 and a given binder and then, to estimate the impact of the zeolite nature (crystal size and Si/Al ratio). For the alumina-type binder, a partial pore blocking is suspected, independently of the crystal size and the Si/Al ratios. A phenomenon of alumination of the zeolite structure was found. For the silica-type binder, the critical parameter is the content of sodium cations inside the binder before the shaping. An ion exchange phenomenon was highlighted and the acid and catalytic properties of the materials collapse but in a reversible way. This impact increases when the crystal size decreases and when the Si/Al ratio increases

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<p>Synchrotron-based sulfur spectroscopy reveals a common concern for marine archaeological wood from seawater: accumulation of reduced sulfur compounds in two pathways. The distribution of sulfur species in the oak wood cell structure was mapped by scanning x-ray spectro-microscopy (SXM). Organically bound sulfur was found within lignin-rich parts, identified mainly as thiols and disulfides by sulfur K-edge x-ray absorption near edge structure (XANES) spectroscopy. Particles of iron sulfides, which may form in the presence of corroding iron, appeared in wood cavities. Cores scanned by x-ray fluorescence (XRF) show that high sulfur accumulation is restricted to the surface layers for the Swedish shipwreck <i>Vasa</i>, while the distribution is rather uniform throughout the hull timbers of the <i>Mary Rose</i>, U.K. Laboratory experiments, exposing fresh pine to simulated seabed conditions, show that the organically bound sulfur develop in reactions between lignin, exposed by cellulose-degrading erosion bacteria, and hydrogen sulfide produced <i>in situ</i> by scavenging sulfate reducing bacteria. With bacteria inoculated from shipwreck samples also iron sulfides formed. The iron sulfides oxidise in high humidity, and are the probable main cause of the numerous outbreaks on the Vasa’s hull of acidic sulfate salts, which were identified by x-ray powder diffraction (XRD). The iron ions catalyse several wood-degrading oxidative processes. Multi-elemental analyses were performed by scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (ESCA). The present amounts of total S remaining in the <i>Vasa</i> and the <i>Mary Rose</i> are estimated to at least 2 tonnes. After the <i>Vasa´s</i> spray treatment with polyethylene glycol solutions ceased in 1979, the continuing oxidation processes are estimated to have produced 2 tonnes of sulfuric acid in the wood. Laboratory experiments to gently neutralize acidic <i>Vasa</i> wood by ammonia gas have been conducted with promising results.</p>