Portland Cement-Based Grouts Enhanced with Basalt Fibers for Post-Tensioned Concrete Duct Filling.

In post-tensioned systems, grouts act as a last line of defense to prevent the penetration of harmful compounds such as chlorides, moisture and other substances that cause corrosion in the prestressing steel. For this reason, improving grouts results in the enhancement of the overall durability of the structure. In this study, the physical properties of grouts with basalt microfiber additions in the amounts of 0.03, 0.07 and 0.10% with respect to the mix volume were evaluated. The fresh properties included flowability and unit mass. Specimens were fabricated to evaluate drying shrinkage, compressive strength, air permeability and rapid permeability to chloride ions. The incorporation of basalt microfibers showed a beneficial effect on the physical properties of the grout by increasing the drying shrinkage resistance and decreasing the permeability compared to the reference mix and two commercial dry prepackaged grouts. The optimal grout mix was the one with a percentage of basalt microfibers of 0.10%, which decreased drying shrinkage by 15.98% at 14 days compared to the reference mix, and permeability to chloride ions decreased by 10.82% compared to the control mix.

Use of quarry waste basalt rock powder as a soil remineralizer to grow soybean and maize.

Production costs in Brazilian agriculture have increased with the rising prices of imported soluble fertilizers. To circumvent this import dependence, low-cost indigenous nutrient sources have been tested, including basalt rock powder (BRP). In this study, we assessed BRP and limestone effects on soil fertility, and soybean and maize dry mass (DM) accumulation. Four greenhouse pots experiments were arranged in a 2 × 4 factorial design with two soils (Clay and Sandy Clay Loam) and four doses of each material (0, 33, 66, and 99 Mg ha-1 BRP and 0, 1, 2, and 4 Mg ha-1 limestone), evaluated in two species (soybean and maize). At the end of the experiments, DM, shoot P and K concentrations, and soil pH and P, K, Ca, and Mg concentrations were assessed as a function of BRP and limestone application. Applying BRP increased DM production and improved soil fertility parameters such as pH, and Ca and P concentrations, with leaf P content also increasing. Meanwhile, limestone only triggered significant changes in pH and soil Ca content.

Effect of Feldspar Substitution by Basalt on Pyroplastic Behaviour of Porcelain Tile Composition.

This work aims to evaluate the effects of feldspar substitution by basalt on porcelain tile composition with respect to its porosity, flexural strength, and pyroplastic deformation. Three ceramic formulations with different amounts of feldspar substituted with basalt, 50% (C1), 75% (C2), and 100% (C3), were evaluated at three different temperatures, 1200, 1220, and 1240 °C. Specifically, the effect of replacing feldspar with basalt on the pyroplastic deformation of ceramic bodies was analysed using optical fleximetry. The porosity of C1 at 1200 °C was 19.3 ± 2.9%, while that of composition C3 was 22.2 ± 0.7% at 1240 °C. The flexural strength was strongly influenced by the temperature. For C1 at 1200 and 1240 °C, flexural strengths of 11.1 ± 0.6 and 22.2 ± 1.9 MPa, respectively, were obtained. Regarding fleximetry, thermal deformation decreased with an increase in the amount of feldspar substituted with basalt. It was observed that C2 and C3 deformed less at high temperatures than the other combinations of compositions and temperature, probably owing to the lower amount of residual glass phase present during cooling. Compositions with higher substitution amounts of basalt (i.e., C2 and C3) exhibited more stable thermal behaviour than C0.

Effects of acidic attack on chemical, mineralogical, and morphological properties of geomaterials.

Exposure of geomaterials to acidic leachates may compromise their structure and functionality due to changes in physicochemical, mineralogical, and hydraulic behavior. The literature identifies the need to evaluate changes in a pure state and in conditions of extreme acidity. This study aimed to evaluate changes in the chemical, mineralogical, and morphological properties of Osorio fine uniform sand (OFS), basalt residual soil (BRS), kaolin (KAO), and bentonite (BEN) exposed to sulfuric acid in concentrations of 0.00 mol/L (distilled water), 0.01 mol/L, and 1.00 mol/L. The tested samples were characterized using X-ray fluorescence spectrometry, X-ray diffraction, thermogravimetry, differential scanning calorimetry, and scanning electron microscopy. The acid attack on geomaterials by contact with the solution 1.00 mol/L has resulted in the solubilization of some constituent minerals, as well as the formation of sulfate minerals, changes in the water dehydration peak in the pores, and mass loss. The morphology of the sand and bentonite particles did not change with exposure to sulfuric acid. The acidic attack resulted in changes in the morphology of the particles for BRS and KAO. The results of this study are important for determining operational parameters of waste containment systems and contaminated areas, as well as for applying geomaterials as founding materials.

Chemical characterization, nano-particle mineralogy and particle size distribution of basalt dust wastes.

Understanding the geochemistry of basalt alteration is central to the study of agriculture systems. Various nano-minerals play an important role in the mobilization of contaminants and their subsequent uptake by plants. We present a new analytical experimental approach in combination with an integrated analytical protocol designed to study basalt alteration processes. Recently, throughout the world, ultra-fine and nano-particles derived from basalt dust wastes (BDW) during "stonemeal" soil fertilizer application have been of great concern for their possible adverse effects on human health and environmental pollution. Samples of BDW utilized were obtained from companies in the Nova Prata mining district in southern Brazil for chemical characterization and nano-mineralogy investigation, using an integrated application of advanced characterization techniques such as X-ray diffraction (XRD), High Resolution-Transmission Electron microscopy (HR-TEM)/Energy Dispersive Spectroscopy (EDS)/(selected-area diffraction pattern) SAED, Field Emission-Scanning Electron Microscopy (FE-SEM/EDS), and granulometric distribution analysis. The investigation has revealed that BDW materials are dominated by SiO2, Al2O3, and Fe2O3, with a complex micromineralogy including alkali feldspar, augite, barite, labradorite, hematite, heulandrite, gypsum, kaolinite, quartz, and smectite. In addition, we have identified a number of trace metals such as Cd, Cu, Cr, and Zn, that are preferentially concentrated into the finer, inhalable, dust fraction and, thus, could present a health hazard in the urban areas around the basalt mining zone. The implication of this observation is that use of these nanometric-sized particulates as soil fertilizer may present different health challenges to those of conventional fertilizers, inviting future work regarding the relative toxicities of these materials. Our investigation on the particle size distribution, nano-particle mineralogy and chemical composition in typical BDW samples highlights the need to develop cleaning procedures to minimize exposure to these natural fertilizing basalt dust wastes and is, thus, of direct relevance to both the industrial sector of basalt mining and to agriculture in the region.

Nanoparticulate mineral matter from basalt dust wastes.

Ultra-fine and nano-particles derived from basalt dust wastes (BDW) during "stonemeal" soil fertilizer application have been the subject of some concern recently around the world for their possible adverse effects on human health and environmental pollution. Samples of BDW utilized were obtained from companies in the mining district of Nova Prata in southern Brazil for chemical characterization and nano-mineralogy investigation, using an integrated application of advanced characterization techniques such as X-ray diffraction (XRD), High Resolution-Transmission Electron microscopy (HR-TEM)/(Energy Dispersive Spectroscopy) EDS/(selected-area diffraction pattern) SAED, Field Emission-Scanning Electron Microscopy (FE-SEM)/EDS and granulometric distribution analysis. The investigation has revealed that BDW materials are dominated by SiO2, Al2O3 and Fe2O3, with a complex micromineralogy including alkali feldspar, augite, barite, labradorite, hematite, heulandrite, gypsum, kaolinite, quartz, and smectite. In addition we have identified a number of trace metals such as Cd, Cu, Cr, Zn that are preferentially concentrated into the finer, inhalable, dust fraction and could so present a health hazard in the urban areas around the basalt mining zone. The implication of this observation is that use of these nanometric-sized particulates as soil fertilizer may present different health challenges to those of conventional fertilizers, inviting future work regarding the relative toxicities of these materials. Our investigation on the particle size distribution, nano-particle mineralogy and chemical composition in typical BDW samples highlights the need to develop cleaning procedures to minimise exposure to these natural fertilizing basalt dust wastes and is thus of direct relevance to both the industrial sector of basalt mining and to agriculture in the region.

Effects of basaltic rock powder added in substrates for Pinus elliottii seedlings / Efeitos de pó de rocha basáltica adicionanado em substratos para mudas de Pinus elliottii Engelm

Even with commercial substrates for forest seedlings available in the market, new mixtures of components, potentially adequate for its physical and minerals characteristics, continue to be studied. The rock crushing powders, sometimes discarded at the end of the process, can be used in the composition of substrates, since it does not pollute and it gives some benefits for plants. This study aimed to evaluate the effects of basaltic rock dust mixed in different percentages with peat-based compost commercial and expanded vermiculite, in seedling production of Pinus elliottii. Five treatments (formulations) were evaluated regarding on the aerial height, the stem diameter and the ratio between aerial part height and stem diameter of seedlings produced by seeds in plastic tubes, as well as its survival after 180 days. In the overall context, the substrate with 10% of basalt powder added to 10% of vermiculite + 80% of commercial compost with peat was the most efficient for seedling development. The seedling survival was not affected by basalt powder.(AU)

Mesmo com diversos substratos comerciais para mudas florestais disponíveis no mercado, novas misturas de componentes, adequados por suas características físicas e minerais, continuam sendo estudadas. O pó residual da britagem de rochas, às vezes descartado ao final do processo, pode ser aproveitado para compor substratos, desde que não seja contaminante e tenha alguma potencialidade de benefícios às plantas. O objetivo deste trabalho foi avaliar os efeitos do pó de rocha basáltica adicionado, em diferentes doses, a um substrato formado por composto comercial a base de turfa e vermiculita expandida, na produção de mudas de Pinus elliottii. Através de cinco tratamentos (formulações), avaliou-se a altura da parte aérea, o diâmetro do coleto e a relação parte aérea/diâmetro do coleto das mudas produzidas por sementes em tubetes plásticos, assim como a sobrevivência após 180 dias. No geral, o substrato com 10% de pó de basalto adicionado a 10% de vermiculita + 80% do composto orgânico comercial foi o mais eficiente ao desenvolvimento das mudas. A sobrevivência das mudas não foi afetada pela presença do pó de basalto.(AU)

Effects of basaltic rock powder added in substrates for Pinus elliottii seedlings / Efeitos de pó de rocha basáltica adicionanado em substratos para mudas de Pinus elliottii Engelm

Even with commercial substrates for forest seedlings available in the market, new mixtures of components, potentially adequate for its physical and minerals characteristics, continue to be studied. The rock crushing powders, sometimes discarded at the end of the process, can be used in the composition of substrates, since it does not pollute and it gives some benefits for plants. This study aimed to evaluate the effects of basaltic rock dust mixed in different percentages with peat-based compost commercial and expanded vermiculite, in seedling production of Pinus elliottii. Five treatments (formulations) were evaluated regarding on the aerial height, the stem diameter and the ratio between aerial part height and stem diameter of seedlings produced by seeds in plastic tubes, as well as its survival after 180 days. In the overall context, the substrate with 10% of basalt powder added to 10% of vermiculite + 80% of commercial compost with peat was the most efficient for seedling development. The seedling survival was not affected by basalt powder.

Mesmo com diversos substratos comerciais para mudas florestais disponíveis no mercado, novas misturas de componentes, adequados por suas características físicas e minerais, continuam sendo estudadas. O pó residual da britagem de rochas, às vezes descartado ao final do processo, pode ser aproveitado para compor substratos, desde que não seja contaminante e tenha alguma potencialidade de benefícios às plantas. O objetivo deste trabalho foi avaliar os efeitos do pó de rocha basáltica adicionado, em diferentes doses, a um substrato formado por composto comercial a base de turfa e vermiculita expandida, na produção de mudas de Pinus elliottii. Através de cinco tratamentos (formulações), avaliou-se a altura da parte aérea, o diâmetro do coleto e a relação parte aérea/diâmetro do coleto das mudas produzidas por sementes em tubetes plásticos, assim como a sobrevivência após 180 dias. No geral, o substrato com 10% de pó de basalto adicionado a 10% de vermiculita + 80% do composto orgânico comercial foi o mais eficiente ao desenvolvimento das mudas. A sobrevivência das mudas não foi afetada pela presença do pó de basalto.

Produção agroecológica de mudas e desenvolvimento a campo de couve-chinesa / Agroecological production of seedlings and field development of Chinese cabbage

O trabalho foi desenvolvido em duas etapas: a produção de mudas de couve-chinesa em bandejas e posterior transplante para o campo, objetivando avaliar o desempenho de diferentes substratos sobre o desenvolvimento da cultura. Para isso determinou-se, tanto na fase de formação das mudas, quanto nas plantas adultas, o comprimento da parte aérea, número de folhas, comprimento da raiz, massa seca da parte aérea, massa seca da raiz e diâmetro do coleto. A etapa de produção de mudas foi conduzida em ambiente protegido, com os seguintes tratamentos: T0 substrato comercial Plantmax® (HA); T1: 100% composto; T2: 95% composto + 2,5% areia + 2,5% pó de rocha; T3: 90% composto + 3% areia + 7% de pó de rocha e T4: 85% composto + 6% areia + 9% pó de rocha. Na produção de mudas, os substratos orgânicos, formulados com 100% e 85% composto, apresentaram melhores resultados, aos 15 e 28 DAS, respectivamente. Os resultados de campo demonstraram que adição de pó de rocha é um fator determinante no desempenho das mudas, sendo os melhores resultados obtidos nas parcelas cultivadas com mudas obtidas nos substratos formulados com 7 e 9% de pó de basalto.

The research was carried out in two stages: the production of seedlings of chinese cabbage in trays with subsequent transplantation for the field, aiming to evaluate the performance of different substrates on the culture development. For this reason it was determined, both at the stage of formation of the seedlings, as in adult plants the length of the aerial part, number of leaves, root length, dry mass of the aerial part, root dry mass and diameter of the root collar. The experiment was conducted in a protected environment with the following treatments: T0 Plantmax substrate® (HA); T1: 100% compound; T2: 95% compost + 2.5% sand + 2.5% rock powder; T3: 90% compost + 3% sand + 7% powdered rock and T4: 85% compost + 6% sand + 9% rock powder. In the production of seedlings, the organic substrates formulated with 100% and 85% compound, had better results, the 15 and 28, respectively. The results of field have shown that the addition of rock powder is a determinant factor in the performance of seedlings, with the best results in the plots cultivated with seedlings obtained in the substrates formulated with 7 and 9% of basalt powder.

Produção agroecológica de mudas e desenvolvimento a campo de couve-chinesa

The research was carried out in two stages: the production of seedlings of chinese cabbage in trays with subsequent transplantation for the field, aiming to evaluate the performance of different substrates on the culture development. For this reason it was determined, both at the stage of formation of the seedlings, as in adult plants the length of the aerial part, number of leaves, root length, dry mass of the aerial part, root dry mass and diameter of the root collar. The experiment was conducted in a protected environment with the following treatments: T0 Plantmax substrate® (HA); T1: 100% compound; T2: 95% compost + 2.5% sand + 2.5% rock powder; T3: 90% compost + 3% sand + 7% powdered rock and T4: 85% compost + 6% sand + 9% rock powder. In the production of seedlings, the organic substrates formulated with 100% and 85% compound, had better results, the 15 and 28, respectively. The results of field have shown that the addition of rock powder is a determinant factor in the performance of seedlings, with the best results in the plots cultivated with seedlings obtained in the substrates formulated with 7 and 9% of basalt powder.

O trabalho foi desenvolvido em duas etapas: a produção de mudas de couve-chinesa em bandejas e posterior transplante para o campo, objetivando avaliar o desempenho de diferentes substratos sobre o desenvolvimento da cultura. Para isso determinou-se, tanto na fase de formação das mudas, quanto nas plantas adultas, o comprimento da parte aérea, número de folhas, comprimento da raiz, massa seca da parte aérea, massa seca da raiz e diâmetro do coleto. A etapa de produção de mudas foi conduzida em ambiente protegido, com os seguintes tratamentos: T0 substrato comercial Plantmax® (HA); T1: 100% composto; T2: 95% composto + 2,5% areia + 2,5% pó de rocha; T3: 90% composto + 3% areia + 7% de pó de rocha e T4: 85% composto + 6% areia + 9% pó de rocha. Na produção de mudas, os substratos orgânicos, formulados com 100% e 85% composto, apresentaram melhores resultados, aos 15 e 28 DAS, respectivamente. Os resultados de campo demonstraram que adição de pó de rocha é um fator determinante no desempenho das mudas, sendo os melhores resultados obtidos nas parcelas cultivadas com mudas obtidas nos substratos formulados com 7 e 9% de pó de basalto.

Produção agroecológica de mudas e desenvolvimento a campo de couve-chinesa

The research was carried out in two stages: the production of seedlings of chinese cabbage in trays with subsequent transplantation for the field, aiming to evaluate the performance of different substrates on the culture development. For this reason it was determined, both at the stage of formation of the seedlings, as in adult plants the length of the aerial part, number of leaves, root length, dry mass of the aerial part, root dry mass and diameter of the root collar. The experiment was conducted in a protected environment with the following treatments: T0 Plantmax substrate® (HA); T1: 100% compound; T2: 95% compost + 2.5% sand + 2.5% rock powder; T3: 90% compost + 3% sand + 7% powdered rock and T4: 85% compost + 6% sand + 9% rock powder. In the production of seedlings, the organic substrates formulated with 100% and 85% compound, had better results, the 15 and 28, respectively. The results of field have shown that the addition of rock powder is a determinant factor in the performance of seedlings, with the best results in the plots cultivated with seedlings obtained in the substrates formulated with 7 and 9% of basalt powder.

O trabalho foi desenvolvido em duas etapas: a produção de mudas de couve-chinesa em bandejas e posterior transplante para o campo, objetivando avaliar o desempenho de diferentes substratos sobre o desenvolvimento da cultura. Para isso determinou-se, tanto na fase de formação das mudas, quanto nas plantas adultas, o comprimento da parte aérea, número de folhas, comprimento da raiz, massa seca da parte aérea, massa seca da raiz e diâmetro do coleto. A etapa de produção de mudas foi conduzida em ambiente protegido, com os seguintes tratamentos: T0 substrato comercial Plantmax® (HA); T1: 100% composto; T2: 95% composto + 2,5% areia + 2,5% pó de rocha; T3: 90% composto + 3% areia + 7% de pó de rocha e T4: 85% composto + 6% areia + 9% pó de rocha. Na produção de mudas, os substratos orgânicos, formulados com 100% e 85% composto, apresentaram melhores resultados, aos 15 e 28 DAS, respectivamente. Os resultados de campo demonstraram que adição de pó de rocha é um fator determinante no desempenho das mudas, sendo os melhores resultados obtidos nas parcelas cultivadas com mudas obtidas nos substratos formulados com 7 e 9% de pó de basalto.

Produção agroecológica de mudas e desenvolvimento a campo de couve-chinesa

The research was carried out in two stages: the production of seedlings of chinese cabbage in trays with subsequent transplantation for the field, aiming to evaluate the performance of different substrates on the culture development. For this reason it was determined, both at the stage of formation of the seedlings, as in adult plants the length of the aerial part, number of leaves, root length, dry mass of the aerial part, root dry mass and diameter of the root collar. The experiment was conducted in a protected environment with the following treatments: T0 Plantmax substrate® (HA); T1: 100% compound; T2: 95% compost + 2.5% sand + 2.5% rock powder; T3: 90% compost + 3% sand + 7% powdered rock and T4: 85% compost + 6% sand + 9% rock powder. In the production of seedlings, the organic substrates formulated with 100% and 85% compound, had better results, the 15 and 28, respectively. The results of field have shown that the addition of rock powder is a determinant factor in the performance of seedlings, with the best results in the plots cultivated with seedlings obtained in the substrates formulated with 7 and 9% of basalt powder.

O trabalho foi desenvolvido em duas etapas: a produção de mudas de couve-chinesa em bandejas e posterior transplante para o campo, objetivando avaliar o desempenho de diferentes substratos sobre o desenvolvimento da cultura. Para isso determinou-se, tanto na fase de formação das mudas, quanto nas plantas adultas, o comprimento da parte aérea, número de folhas, comprimento da raiz, massa seca da parte aérea, massa seca da raiz e diâmetro do coleto. A etapa de produção de mudas foi conduzida em ambiente protegido, com os seguintes tratamentos: T0 substrato comercial Plantmax® (HA); T1: 100% composto; T2: 95% composto + 2,5% areia + 2,5% pó de rocha; T3: 90% composto + 3% areia + 7% de pó de rocha e T4: 85% composto + 6% areia + 9% pó de rocha. Na produção de mudas, os substratos orgânicos, formulados com 100% e 85% composto, apresentaram melhores resultados, aos 15 e 28 DAS, respectivamente. Os resultados de campo demonstraram que adição de pó de rocha é um fator determinante no desempenho das mudas, sendo os melhores resultados obtidos nas parcelas cultivadas com mudas obtidas nos substratos formulados com 7 e 9% de pó de basalto.

Caracterização mineralógica dos solos derivados de rochas efusivas no Planalto Sul de Santa Catarina, Brasil / Mineralogical characterization of soils derived from effusive rocks from plateau in south Santa Catarina, Brazil

A presença simultânea de gibbsita, caulinita, argilominerais 2:1 com polímeros de hidróxi- Al (2:1HE) e interestratificados em solos ácidos e dessaturados do Sul do Brasil pode ser considerada contraditória, mas não rara. Como a correta identificação destes argilominerais é de difícil execução, a evolução destes solos pode acabar sendo atribuída simplesmente a uma escala de intemperismo moderado. Para melhor compreender a gênese dos solos da região do Planalto Sul de Santa Catarina, foram desenvolvidos estudos mineralógicos da fração argila e das respectivas rochas matriz de sete perfis de solo ao longo de duas topossequências. As análises mineralógicas foram realizadas por difratometria de raios X (DRX), utilizando os pré-tratamentos usuais e um pré-tratamento com hidróxido de sódio (NaOH) a 3,5 mol L-1 a quente (250ºC). Os teores dos óxidos de Si, Al e Fe foram determinados após a digestão das amostras com ataque sulfúrico. As rochas apresentaram mineralogia similar, exceto nas quantidades de plagioclásios, piroxênios e quartzo. Todos os solos apresentaram caulinitas de baixa cristalinidade e resquícios de argilominerais 2:1 sob a forma de interestratificados e/ou 2:1HE, que permaneceram nos solos devido à intercalação dos polímeros de Al e/ou Fe nas entrecamadas. As diminutas proporções de gibbsita são decorrentes do efeito complexante da matéria orgânica do solo (MOS) sobre a cristalização dos hidróxidos de Al e também, devido ao ambiente lixiviante que não foi sufi cientemente severo a ponto de predominar os processos de alitização. Nos Nitossolos Vermelhos o principal processo de alteração do material originário foi a monossialitização, enquanto os Cambissolos Háplicos apresentaram processo de hidrólise tendendo para a alitização.(AU)

The simultaneous presence of gibbsite, kaolinite, 2:1 clay minerals with Al-hydroxy polymers and interstratified minerals in acid soils and desaturated in southern Brazil can be seen as contradictory, but not rare. How correct identification of these clay minerals is difficult to perform, the evolution of these soils may simply end up being attributed to a range of moderate weathering. To better understand the genesis of soils in southern highlands of Santa Catarina, studies were conducted of mineralogical clay rocks and their array of seven soil profiles along two topossequences. The mineralogical analyzes were performed by X-ray diffractometry (XRD) using the usual pretreatment and a pretreatment with hot (250°C) 3.5 mol L-1 solution. The levels of oxides of Si, Al and Fe were determined after dissolving the samples in sulfuric acid. The rocks show similar mineralogy, except in amounts of plagioclase, pyroxene and quartz. All soils had low crystallinity of kaolinite and traces of 2:1 clay minerals in the form of interstratifi ed and/or 2:1 clay minerals with Al-hydroxy polymers, that/ which remained in the soil due to intercalation of the polymers of Al and / or Fe in interlayers. The diminutive proportions of gibbsite are due to the complex effect of soil organic matter (SOM) on the crystallization of Al hydroxides and also due to the leaching environment was not suffi ciently severe as to dominate the processes of alitization. In Kandiudox the main process of changing the source material was monossialitization while Haplumbrept showed hydrolysis process tending to alitization.(AU)

Caracterização mineralógica dos solos derivados de rochas efusivas no Planalto Sul de Santa Catarina, Brasil / Mineralogical characterization of soils derived from effusive rocks from plateau in south Santa Catarina, Brazil

A presença simultânea de gibbsita, caulinita, argilominerais 2:1 com polímeros de hidróxi- Al (2:1HE) e interestratificados em solos ácidos e dessaturados do Sul do Brasil pode ser considerada contraditória, mas não rara. Como a correta identificação destes argilominerais é de difícil execução, a evolução destes solos pode acabar sendo atribuída simplesmente a uma escala de intemperismo moderado. Para melhor compreender a gênese dos solos da região do Planalto Sul de Santa Catarina, foram desenvolvidos estudos mineralógicos da fração argila e das respectivas rochas matriz de sete perfis de solo ao longo de duas topossequências. As análises mineralógicas foram realizadas por difratometria de raios X (DRX), utilizando os pré-tratamentos usuais e um pré-tratamento com hidróxido de sódio (NaOH) a 3,5 mol L-1 a quente (250ºC). Os teores dos óxidos de Si, Al e Fe foram determinados após a digestão das amostras com ataque sulfúrico. As rochas apresentaram mineralogia similar, exceto nas quantidades de plagioclásios, piroxênios e quartzo. Todos os solos apresentaram caulinitas de baixa cristalinidade e resquícios de argilominerais 2:1 sob a forma de interestratificados e/ou 2:1HE, que permaneceram nos solos devido à intercalação dos polímeros de Al e/ou Fe nas entrecamadas. As diminutas proporções de gibbsita são decorrentes do efeito complexante da matéria orgânica do solo (MOS) sobre a cristalização dos hidróxidos de Al e também, devido ao ambiente lixiviante que não foi sufi cientemente severo a ponto de predominar os processos de alitização. Nos Nitossolos Vermelhos o principal processo de alteração do material originário foi a monossialitização, enquanto os Cambissolos Háplicos apresentaram processo de hidrólise tendendo para a alitização.

The simultaneous presence of gibbsite, kaolinite, 2:1 clay minerals with Al-hydroxy polymers and interstratified minerals in acid soils and desaturated in southern Brazil can be seen as contradictory, but not rare. How correct identification of these clay minerals is difficult to perform, the evolution of these soils may simply end up being attributed to a range of moderate weathering. To better understand the genesis of soils in southern highlands of Santa Catarina, studies were conducted of mineralogical clay rocks and their array of seven soil profiles along two topossequences. The mineralogical analyzes were performed by X-ray diffractometry (XRD) using the usual pretreatment and a pretreatment with hot (250°C) 3.5 mol L-1 solution. The levels of oxides of Si, Al and Fe were determined after dissolving the samples in sulfuric acid. The rocks show similar mineralogy, except in amounts of plagioclase, pyroxene and quartz. All soils had low crystallinity of kaolinite and traces of 2:1 clay minerals in the form of interstratifi ed and/or 2:1 clay minerals with Al-hydroxy polymers, that/ which remained in the soil due to intercalation of the polymers of Al and / or Fe in interlayers. The diminutive proportions of gibbsite are due to the complex effect of soil organic matter (SOM) on the crystallization of Al hydroxides and also due to the leaching environment was not suffi ciently severe as to dominate the processes of alitization. In Kandiudox the main process of changing the source material was monossialitization while Haplumbrept showed hydrolysis process tending to alitization.

Microbial communities at the borehole observatory on the Costa Rica Rift flank (Ocean Drilling Program Hole 896A).

The microbiology of subsurface, hydrothermally influenced basaltic crust flanking mid-ocean ridges has remained understudied, due to the difficulty in accessing the subsurface environment. The instrumented boreholes resulting from scientific ocean drilling offer access to samples of the formation fluids circulating through oceanic crust. We analyzed the phylogenetic diversity of bacterial communities of fluid and microbial mat samples collected in situ from the observatory at Ocean Drilling Program Hole 896A, drilled into ~6.5 million-year-old basaltic crust on the flank of the Costa Rica Rift in the equatorial Pacific Ocean. Bacterial 16S rRNA gene sequences recovered from borehole fluid and from a microbial mat coating the outer surface of the fluid port revealed both unique and shared phylotypes. The dominant bacterial clones from both samples were related to the autotrophic, sulfur-oxidizing genus Thiomicrospira. Both samples yielded diverse gamma- and alphaproteobacterial phylotypes, as well as members of the Bacteroidetes, Planctomycetes, and Verrucomicrobia. Analysis of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) genes (cbbL and cbbM) from the sampling port mat and from the borehole fluid demonstrated autotrophic carbon assimilation potential for in situ microbial communities; most cbbL genes were related to those of the sulfur-oxidizing genera Thioalkalivibrio and Thiomicrospira, and cbbM genes were affiliated with uncultured phylotypes from hydrothermal vent plumes and marine sediments. Several 16S rRNA gene phylotypes from the 896A observatory grouped with phylotypes recovered from seawater-exposed basalts and sulfide deposits at inactive hydrothermal vents, but there is little overlap with hydrothermally influenced basaltic boreholes 1026B and U1301A on the Juan de Fuca Ridge flank, suggesting that site-specific characteristics of Hole 896A (i.e., seawater mixing into borehole fluids) affect the microbial community composition.

Qualidade da pastagem nativa obtida por diferentes métodos de amostragem e em diferentes solos na Apa do Ibirapuitã, Brasil

Heterogeneous ecosystems are found in the state of Rio Grande do Sul as a consequence of the great number of soil types and variation in altitude and climate. These conditions reflect on the great variety of flora present in the grassland communities. The Area of Environmental Protection of the Ibirapuitã (APA of Ibirapuitã) is the only conservation unit under federal jurisdiction representative of the Campos bioma in Brazil. The objective of this work was to obtain information about the quality of the natural pasture on three types of soils in APA of Ibirapuitã: Superficial Basalt, Deep Basalt and Sandy, using three methods: total monthly accumulation using cages, hand plucking and regular cut. The data were collected monthly between October/2001 and September/2002. The native pasture on Superficial Basalt soil had superior nutritional quality when compared to the others, as seen in the results of different quality analyses. The pasture sampling methods did not influence the neutral detergent fibre content. The results indicate the hand plucking method, as the best for native pasture quality evaluations due to its effectiveness and facility of collection.

O estado do Rio Grande do Sul apresenta ecossistemas heterogêneos, devido ao grande número de tipos de solo e à variação em altitude e clima, que se reflete na diversidade da composição florística das diferentes comunidades vegetais. A Área de Proteção Ambiental do Ibirapuitã (APA do Ibirapuitã), é a única unidade de conservação federal, representante do bioma campos sulinos no Brasil. O objetivo deste trabalho foi obter informação sobre a qualidade do campo natural oriundo de três tipos de solos predominantes na APA do Ibirapuitã: Basalto superficial, Basalto profundo e Arenito obtidos por três formas de amostragem: Corte de emparelhamento, Simulação de pastejo através de coleta manual e Corte total acima da fração mantilho. Os dados foram coletados mensalmente, no período de outubro/2001 a setembro/2003. A pastagem nativa no solo de Basalto superficial apresenta forragem com qualidade nutricional superior quando comparado ao Basalto profundo e ao Arenito, comprovada pelas diferentes análises de qualidade realizadas. O método de coleta de amostras de forragem de pastagem nativa somente não influencia os resultados da análise de Fibra em Detergente Neutro. Os resultados indicam a simulação de pastejo como um método adequado de amostragem para avaliação da qualidade da pastagem nativa, devido à sua efetividade e facilidade de coleta.

Qualidade da pastagem nativa obtida por diferentes métodos de amostragem e em diferentes solos na Apa do Ibirapuitã, Brasil

Heterogeneous ecosystems are found in the state of Rio Grande do Sul as a consequence of the great number of soil types and variation in altitude and climate. These conditions reflect on the great variety of flora present in the grassland communities. The Area of Environmental Protection of the Ibirapuitã (APA of Ibirapuitã) is the only conservation unit under federal jurisdiction representative of the Campos bioma in Brazil. The objective of this work was to obtain information about the quality of the natural pasture on three types of soils in APA of Ibirapuitã: Superficial Basalt, Deep Basalt and Sandy, using three methods: total monthly accumulation using cages, hand plucking and regular cut. The data were collected monthly between October/2001 and September/2002. The native pasture on Superficial Basalt soil had superior nutritional quality when compared to the others, as seen in the results of different quality analyses. The pasture sampling methods did not influence the neutral detergent fibre content. The results indicate the hand plucking method, as the best for native pasture quality evaluations due to its effectiveness and facility of collection.

O estado do Rio Grande do Sul apresenta ecossistemas heterogêneos, devido ao grande número de tipos de solo e à variação em altitude e clima, que se reflete na diversidade da composição florística das diferentes comunidades vegetais. A Área de Proteção Ambiental do Ibirapuitã (APA do Ibirapuitã), é a única unidade de conservação federal, representante do bioma campos sulinos no Brasil. O objetivo deste trabalho foi obter informação sobre a qualidade do campo natural oriundo de três tipos de solos predominantes na APA do Ibirapuitã: Basalto superficial, Basalto profundo e Arenito obtidos por três formas de amostragem: Corte de emparelhamento, Simulação de pastejo através de coleta manual e Corte total acima da fração mantilho. Os dados foram coletados mensalmente, no período de outubro/2001 a setembro/2003. A pastagem nativa no solo de Basalto superficial apresenta forragem com qualidade nutricional superior quando comparado ao Basalto profundo e ao Arenito, comprovada pelas diferentes análises de qualidade realizadas. O método de coleta de amostras de forragem de pastagem nativa somente não influencia os resultados da análise de Fibra em Detergente Neutro. Os resultados indicam a simulação de pastejo como um método adequado de amostragem para avaliação da qualidade da pastagem nativa, devido à sua efetividade e facilidade de coleta.