Thesis (M.S.)--Oregon State University, 1998. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.S.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xiii, 178 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 112-115).

Honors Project--Smith College, Northampton, Mass., 2009. / Includes bibliographical references.

TPC is a 16 000 hectare estate located in Moshi, Tanzania and is currently planted under 8 800 hectares of sugarcane and produces over 60 000 tons of sugar per annum. The influence of volcanic parent material and volcanic ash over TPC, together with the alluvial nature of many of the soils, has imparted a unique combination of soil mineralogical, physical and chemical properties. Furthermore, irrigation with poor quality water has led to sodicity problems on the estate. Understanding the mineralogy and sodicity effects on soil hydraulic properties across the estate can lead to better irrigation management where it is important to prevent the build-up of salts due to over-irrigation. In response to this need, a study was carried out with the aim of characterising the mineralogical, physical and chemical properties in the five management areas of the estate (North, East, West, South and Kahe), in order to determine the relationships between various measured parameters. A total of 70 fields across TPC, as well as four sites outside the estate and two ash layers, were chosen for sampling. Undisturbed soil cores and bulk samples were collected from the A and B horizons from 45 of these fields and the four sites outside. Selected fields were sampled at more than one site to assess field variability, and where cane growth was patchy selected fields were sampled in a patch of poorly growing cane and an adjacent patch of better cane growth. Bulk soil samples were collected from the remaining fields and the two ash layers. Double ring infiltration measurements were carried out on 25 of the selected fields. X-ray diffraction, transmission electron microscopy and aluminium, iron and silica extractions were carried out to determine the mineralogy. Physical and chemical measurements included water retentivity, saturated hydraulic conductivity, bulk density, particle size distribution, organic carbon, pH (H2O), electrical conductivity, water soluble and exchangeable cations (Ca, Mg, K and Na), cation exchange capacity and clay specific surface area. The particle size distribution showed that the soils were mainly loams and sandy loams. Organic carbon values were generally greater in the A horizon compared to the B horizon and varied between 0.4 and 2.5 % in the topsoil and 0.3 and 2.1 % (with the exception of field 11 which had an organic carbon of 4.0 %) in the subsoil. X-ray diffraction patterns of sand and silt fractions were dominated by sanidine while clay patterns were weak and had high backgrounds and very broad peaks, suggesting the presence of poorly ordered material in the clay fraction. The Al and Fe extraction methods and electron micrographs indicated that this poorly ordered material was allophane. However, the dominant clay mineral across the estate was halloysite, in both tubular and spheroidal form, as well as very small (<< 0.5 μm) kaolinite particles. There was also gibbsite in some of the samples analysed. The combination of allophane, halloysite, kaolinite and gibbsite indicated that the primary volcanic minerals have weathered to various degrees across the estate. This is reflected in the alluvial nature of the soils where less weathered material has been periodically deposited onto older, more weathered material over some parts of the estate. The south and west areas had a slightly higher Alo + ½ Feo ratio than the other areas in both the topsoil (1.07 and 0.95, respectively) and the subsoil (1.16 and 1.06, respectively), a possible consequence of less weathered alluvial material that was deposited in these areas. Although the concentration of allophane was low (< 5 %), even in the south and west areas, its presence greatly increased the clay specific surface area (up to 145.94 m2 g-1) and consequently had a significant influence on the soil physical and chemical properties. Water retention across TPC was high, particularly at the lower matric potentials (between 0.13 and 0.45, and 0.09 and 0.24 m3 m-3 at -33 kPa and -1500 kPa, respectively). The high water retention is a result of allophane which gives the soils a high adsorption capacity and a porosity that is dominated by micro-pores. Generally, the south area had the highest water retention at the various measured matric potentials which corresponds to the higher allophane content. Variability in water retentivity across areas and within fields limited further interpretation and correlation with the mineralogical results. Infiltration rate was lowest in the south (60.85 mm hr-1) and highest in the Kahe area (171.20 mm hr-1). The main factor influencing the final infiltration rate was the concentration of sodium in the soil, with higher concentrations causing soil dispersion and blockage of soil pores. Clay dispersion has led to the development of calcareous surface crusts and reduced porosity, thus reducing the infiltration rate. Sodium concentration in the soil is likely to have had a dominating effect over the mineralogical composition of the soil. Poor cane growth in the south and west areas corresponded to higher pH (up to 10.32), electrical conductivity (up to 614 mS m-1), sodium absorption ratio (up to 20.63) and water soluble and exchangeable sodium (up to 53.20 mmolc l-1 and 14.87 cmolc kg-1 soil, respectively) in these areas. The soils are thus more dispersive and the combination of sodicity and allophane has resulted in “fluffy” soils with small particles clogging soil pores and thus surface crusts have formed easily. The combined effect of mineralogy and sodicity in the south is further complicated by the presence of perched water tables. High adsorption capacities and the dominance of micro-pores allow the occurrence of significant capillary rise which brings salts to the soil surface, further exacerbating the sodicity problem. Therefore, over-irrigation should be avoided where soils are prone to sodicity from a combination of irrigation with poor quality water, perched water tables and strong capillary rise action. Fields which are currently experiencing the negative effects of high sodicity, require irrigation with good quality water and adequate sub-surface drainage to ensure the leaching of salts. Further studies with specific focus on the south and west areas would be beneficial in accounting for the variability and in drawing correlations between the mineralogy and sodium content of the soils with the other measured properties. Fields which are prone to increased sodicity through over-irrigation with poor quality water, have strong capillary rise from perched water tables and which require remediation through sub-surface drains can thus be distinguished and the factors influencing sugarcane growth can be more clearly understood. Growth depends on the combination of these soil’s unique mineralogy and sodium content and the influence they have on the infiltration rate, adsorption capacity, micro-porosity and capillary rise from the water table. For future work, water movement modelling to predict saturated and unsaturated flow, as well as in situ measures of unsaturated flow, will lead to further understanding of the soil hydraulic properties and aid in improved irrigation management. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

The Kumamoto earthquake of April 2016 produced two foreshocks of moment magnitude 6.0 and 6.2 and a mainshock of 7.0, which should have been followed by widespread and intense soil liquefaction. A Geotechnical Extreme Events Reconnaissance team (GEER) led by Professor Rob Kayen of UC Berkley was dispatched to the Kumamoto Plain--which is in Kumamoto Prefecture, the southern main island of Japan--immediately following the earthquake. The Japanese and U.S. engineers in the GEER team observed mostly minor and sporadic liquefaction, which was unexpected as the local site geology, known soil stratigraphy, and intensity of the seismic loading made the Kumamoto Plain ripe for soil liquefaction. The paucity and limited scale of liquefaction shows a clear gap in our understanding of liquefaction in areas with volcanic soils. This study is a direct response to the GEER team's preliminary findings regarding the lack of significant liquefaction. An extensive literature review was conducted on the Kumamoto Plain and its volcanic soil. The liquefaction of the 2016 Kumamoto Earthquake was also researched, and several sites were selected for further analysis. Four sites were analyzed with SPT, CPT, and laboratory testing during the spring of 2017. A slope stability analysis and undisturbed testing were performed for specific sites. The results of the analysis show a general over-prediction of SPT and CPT methods when determining liquefaction hazard. The Youd et al. (2001) NCEES method was the most consistent and accurate in determining liquefaction. The soils in the area including sands and gravels had high levels of fines, plasticity, and organic matter due to the weathering of volcanic ash and pyroclastic material. The volcanically derived coarse-grained soils may also have exhibited some crushability, which gave lower resistance readings. Filled river channels had the worst liquefaction with natural levees and the Kumamoto flood plains having only minor liquefaction. Publicly available boring logs rarely showed laboratory test data of bore holes which led to a general inaccurate soil classification. Boring logs were also not updated with laboratory classifications and data. Undisturbed cyclic triaxial testing of soils at one site showed that volcanic soils had relatively high resistance to soil liquefaction, though drying of samples may have compromised the results. Embankment cracking at one test location was calculated a lateral spread and a seismic slope failure along the pyroclastic flow deposit.

Made available in DSpace on 2015-03-26T13:53:19Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1619927 bytes, checksum: 2e509eb4db50391173d4bb2ac58780ae (MD5) Previous issue date: 2011-05-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Antarctic sea, the higher humidity, light and temperature favor the process of hydrolysis of minerals and leaching of bases, in addition to colonization by denser vegetation cover and various activities and a greater presence of birds, resulting in physical and chemical changes of soil known distinct from most of the continent. Studies seeking to understand the processes and the relationships between pedogenetic soil and ecosystems are scarce, especially in the volcanic islands of the Archipelago South Schetlands. This study aimed to broadly examine the chemical and physical characteristics of the volcanic soils of different ages and the influence of soil formation in ornithogenic recent volcanic island of Deception and Penguin. Specifically, the study characterized the chemical, physical and mineralogical to study soil processes that operate in regions of recent volcanism in the Antatctic and its influence on terrestrial. We collected five soil profiles on Deception Island and three on Penguin Island during the summer of 2008. The soils were classified as Cryossols and Leptosols (WRB) and Gelisols and Inceptsols (Soil Taxonomy).Invariably the soil samples had high amounts of gravel and low clay. Soils are developing with incipient distinction between horizons, keeping a strong relationship with the source material. From a chemical standpoint are eutrophic soils with high pH values, except the profile P3 of Penguin Island which showed lower values of the other profiles. The values of P extracted by Mehlich-1 are low forthe profiles without influence of seabirds It became evident the influence of the source material in the chemical composition of soils. Analyses of X-rays showed a mineralogical assemblage composed mainly of plagioclase, potassium feldspar, and pyroxene in addition to smectite clay soil. The presence of primary minerals in the clay fraction shows strong physical weathering and incipient chemical change. According to chemical extractions and values Feo, Alo and Sio was evident in the presence of allophane profiles of Penguin Island, Deception Island while also exists in the presence of some crystalline minerals, but in smaller proportions. Unlike the soils in areas of influence of birds in other parts of Antarctica, the profiles analyzed showed no evidence of phosphate, however, it is clear the influence of seabirds in the development of vegetation, accumulation of organic matter and development of soil fauna. / Na Antártica marítima, a maior umidade, luminosidade e temperatura favorecem os processos de hidrólise dos minerais e lixiviação de bases, além da colonização por coberturas vegetais mais densas e diversas e maior presença de atividades de aves, resultando em alterações físico-químicas dos solos reconhecidamente distintas da maior parte do continente. Estudos que buscam compreender os processos pedogenéticos e as relações entre solo e ecossistemas são escassos, sobretudo nas ilhas vulcânicas do Arquipélago Schetlands do Sul. O presente estudo objetivou de forma geral estudar as características químicas e físicas dos solos vulcânicos de diferentes idades e verificar a influência da ornitogênese na formação de solos vulcânicos recentes das ilhas Deception e Penguin. Especificamente o trabalho caracterizou os aspectos químicos, físicos e mineralógicos a fim de estudar os processos pedológicos que operam em regiões de vulcanismo recente na Antártica e sua influência nos ecossistemas terrestres. Foram coletados cinco perfis de solo na Ilha Deception e três na Ilha Penguin durante o verão de 2008. Os solos estudados foram classificados como Cryosols e Leptosols (WRB) e Gelisols e Inceptsols (Soil Taxonomy). Invariavelmente os perfis estudados apresentaram altos valores de cascalho e baixos teores de argila. São solos com desenvolvimento incipiente com fraca distinção entre horizontes, guardando forte relação com o material de origem. Do ponto de vista químico são solos eutróficos com valores de pH elevados, exceto o perfil P3 da ilha Penguin que apresentou valores mais baixos dos demais perfis. Os valores de P extraído por Mehlich-1 são baixos para os perfis sem influencia ornitogênica, ficando evidente a influencia do material de origem na composição química dos solos. As análises de Raios-X mostraram uma assembleia mineralógica composta basicamente por plagioclásios, feldspatos potássicos, piroxênio além de esmectita na fração argila dos solos. A presença de minerais primários na fração argila indica forte intemperismo físico e incipiente alteração química. De acordo com as extrações químicas e com os valores de Feo, Alo e Sio ficou evidente a presença de alofana nos perfis da ilha Penguin, enquanto na ilha Deception também existe a presença de minerais pouco cristalinos, mas em menores proporções. Diferentemente dos solos estudados em áreas de influencia de aves em outras partes da Antártica, os perfis analisados não apresentaram indícios de fosfatização, no entanto, é evidente a influencia da avifauna no desenvolvimento da cobertura vegetal, acúmulo de matéria orgânica e desenvolvimento da fauna do solo.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第22130号 / 農博第2376号 / 新制||農||1073(附属図書館) / 学位論文||R1||N5238(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 德地 直子, 教授 北島 薫, 准教授 舘野 隆之輔 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-07-27T19:46:53Z No. of bitstreams: 1 2012 - Alexandre Muselli Barbosa.pdf: 9021333 bytes, checksum: 5ab49dd0b9a0835ab179fedb0302417a (MD5) / Made available in DSpace on 2017-07-27T19:46:53Z (GMT). No. of bitstreams: 1 2012 - Alexandre Muselli Barbosa.pdf: 9021333 bytes, checksum: 5ab49dd0b9a0835ab179fedb0302417a (MD5) Previous issue date: 2012-02-29 / FAPERJ / The objective of this work was the environmental study of the northern flank of the volcano Cotopaxi, Ecuador, with the focus on the acting of weathering processes and climate in the soil formation processes and cryopedogenesis, in a transect ranging from 3979 to 4885m. For the study a survey and zoning of the vegetation was conducted; digital geomorphologic analysis, consisting of elevation, slope, curvature, illumination and radiation exposure, geological study, monitoring of temperatures of air and at five soil depths, in three different elevation points; description and collection of six representative soil profiles, according to the variation of vegetation, topography, presence of snow and elevation; and evaluation of soil composition through analysis of petrographic, mineralogical, physical and chemical properties of soils. The vegetation covering the slope is the P?ramo, varying in size according to elevation and increasing of ice sheets over the soil, which occurs up to 4885 m, and the biota is represented by extremophile organisms. The geology of the Cotopaxi volcano is complex due to the recent volcanic activity, where the ejected material is of Andesite-rhyolite, as identified by the petrography, with large deposits of tephra, and an area of debris deposition. The geomorphology is characteristic of a stratovolcano, with conical and symmetric formations, with broad base and gentle slope, headed for a peak with high altitude and slopes, the slopes are full of drainage systems and erosional features, and in the lower portions of the landscape there are sedimentary deposits of periglacial origin. The registered temperatures showed that the soil are kept warmer than the air temperature for the three elevations, even in the systems that present ice coverage, showing that the soil has thermal insulation properties. The soils are stratified, with layers of ash and lapilli interspersed, with pumices, predominantly coarse texture and low clay content. The mineralogical analyzes indicated the presence of easily weathered minerals such as apatite, olivine, pyroxenes and feldspars. The minerals found influence in the soil chemical data, with high levels of Na, P and K, and the large amounts of Fe, from the ferromagnesian minerals in the parent material. The six profiles described were identified into two systems of soil classification, the WRB - FAO and the USDA - Soils Taxonomy. As for the WRB, three soils were classified as Regosols, two as Leptosols, and one as Cryosol. In the Soil Taxonomy, three were classified as Inceptisols, two as Entisols and one as Gelisol. The coarse texture and presence of pumice material, together with the large presence of easily weathered minerals, show the dominance of physical weathering over chemical reactions in the alteration of parent material of the Cotopaxi volcano. This fact results in poor soil development, also influenced by the climate, type of vegetation, and the recent deposition of material from the volcanic activity. Since the data of soil temperature was only of one year, it is not possible to determine the soil thermal dynamics, requiring continuing the monitoring to acquire data on a longer time scale. / O objetivo deste trabalho foi realizar o estudo ambiental do flanco norte do vulc?o Cotopaxi, Equador, com o enfoque da a??o dos processos intemp?ricos e clim?ticos na forma??o dos solos e processos criopedog?nicos, em um transecto variando entre 3.979 a 4.885m de altitude. Para o estudo foi realizado o levantamento e zoneamento vegetal; an?lise geomorfol?gica digital, composta por eleva??o, declividade, curvatura, face de exposi??o e radia??o; estudo geol?gico; monitoramento das temperaturas em cinco profundidades do solo e do ar em tr?s pontos de eleva??o diferentes; descri??o e coleta de seis perfis representativos, de acordo com a varia??o de vegeta??o, topografia, presen?a de neve e eleva??o; e avalia??o da composi??o do solo, atrav?s de an?lises petrogr?ficas, mineral?gicas, f?sicas e qu?micas dos solos. A vegeta??o que recobre a encosta ? o P?ramo, variando de porte de acordo com a eleva??o e o aumento das camadas de gelo sobre o solo, sendo este presente at? os 4.885m, e a biota ? representada por organismos extrem?filos. A geologia do Vulc?o Cotopaxi ? complexa devido a recentes atividades vulc?nicas, sendo o material expelido Riol?to-Andesito, comprovadas pelas an?lises petrogr?ficas, com grandes deposi??es de tephra, e ?rea de deposi??es de corrida de detritos. A geomorfologia ? caracter?stica de estrato vulc?es, forma??es c?nicas e sim?tricas, com base ampla e declive suave, indo a cumes com elevada altitude e grandes declividades, suas encostas s?o repletas de sistemas de drenagem e fei??es erosivas, e nas por??es mais baixas ocorrem dep?sitos sedimentares de origem periglacial. As temperaturas registradas mostraram que o solo se mantem em n?veis mais elevados que a temperatura do ar para as tr?s eleva??es, mesmo nos sistemas que apresentam cobertura de gelo, mostrando que o solo possui propriedades de isolamento t?rmico. Os solos s?o estratificados, com camadas intercaladas de cinza e lapilli, pedregosos, com textura predominantemente grosseira e baixo conte?do de argila. As an?lises mineral?gicas apontaram a presen?a de minerais facilmente intemperiz?veis, como apatita, as olivinas, os pirox?nios e os feldspatos. Os minerais encontrados refletem nos dados qu?micos dos solos, com teores elevados dos elementos de Na, P e K, al?m dos altos teores de Fe, pelo material de origem de mineral ferromagnesiano. Os seis perfis descritos foram identificados em dois sistemas de classifica??o de solos, o WRB da FAO e o Soil Taxonomy do USDA. Sendo para o WRB, tr?s solos classificados como Regosols, dois Leptosols e um Cryosol. No Soil Taxonomy, tr?s solos s?o Inceptisols, dois Entisols e um Gelisol. A presen?a de textura grosseira e rochas vesiculadas, juntamente com a grande presen?a de minerais facilmente intemperiz?veis, evidenciam o predom?nio do intemperismo f?sico sobre o qu?mico na altera??o do material de origem do Vulc?o Cotopaxi. Este fato resulta no fraco desenvolvimento dos solos, tamb?m influenciado pelo clima, tipo de vegeta??o e as recentes deposi??es de material pela atividade vulc?nica. Como os registros de temperatura do solo foram de apenas um ano, n?o ? poss?vel determinar a sua din?mica t?rmica, sendo necess?ria a continuidade do monitoramento para a obten??o de dados com maior dura??o de tempo.

Selenium (Se) is an element with important health implications that is emitted in significant amounts from volcanoes. Attracted by the fertility of volcanic soils, around 10% of the world population lives within 100 km of an active volcano. Nevertheless, the behaviour of Se in volcanic environments is poorly understood. Therefore, the main aim of this thesis is to investigate the role of soils in the Se cycling in volcanic environments. Prior to the geochemical studies, precise and accurate methods for the determination of Se contents, speciation and isotopic signatures were developed. Afterwards, a combination of field studies and lab controlled experiments were performed with soils from two contrasting European volcanic settings: Mount Etna in Sicily (Italy) and Mount Teide in Tenerife (Spain). The results showed a strong link between Se behaviour and soil development, indicating that Se mobility in volcanic soils is controlled by sorption processes and soil mineralogy. / El selenio (Se) tiene afectas sobre la salud y es emitido por los volcanes. Atraída por la fertilidad de los suelos volcánicos, un 10% de la población mundial vive <100 km de volcanes activos. Sin embargo, el comportamiento geoquímico del Se en ambientes volcánicos es aún poco conocido. El objetivo de esta tesis es contribuir a la comprensión del papel del suelos en el ciclo del Se en medios volcánicos. En una primera etapa se desarrollaron métodos analíticos para determinar el contenido, la especiacíon y las relaciónes isotópicas del Se. Los estudios geoquímicos se realizaron con suelos de dos lugares con características muy distintas: el Monte Etna (Italia) y el volcán Teide (Tenerife). Los estudios de terreno y de laboratorio revelaron una gran interrelación entre el comportamiento del Se y el desarrollo de suelos, y que la movilidad de Se está controlado por los procesos de adsorción y la mineralogía en suelos volcánicos.

El propósito de esta investigación es mejorar los parámetros geotécnicos del suelo volcánico granular con la adición de cemento Portland tipo I. Primero, se realiza el ensayo de Granulometría y se clasifico mediante SUCS como una arena con grava pobremente gradada y según AASHTO como A-1-b. Por otro lado, se realizó el ensayo de Proctor y se obtuvo una Densidad Seca Máxima de 1.21 kg/cm2 con un Contenido de Humedad Optimo de 17.8%. Además, los resultados del ensayo de Corte Directo indico un ángulo de fricción 33.5°, una cohesión de 0.0 kg/cm2. El segundo paso fue realizar el ensayo de Proctor a muestras con adiciones de 3%, 5%, 7% y 9% de cemento, los resultados óptimos fueron al 5% de adición. El tercer paso, se realizó el ensayo de Corte Directo las mezclas de 3%, 5% y 7% a 7 y 14 días de curado, los resultados indicaron un incremento de 14.6% a 79.1% en el ángulo de fricción en comparación del suelo natural y un incremento de 25.8% a 161.5 % en la resistencia al corte. También, se muestra el comportamiento de la deformación volumétrica, presentando una mayor contracción cuando se aplica un esfuerzo normal de 1 kg/cm2 y una mayor expansión cuando se aplica un esfuerzo normal de 4 kg/cm2. Finalmente, los parámetros del ensayo de Proctor indican a la mezcla con 5% la más óptima y los parámetros del ensayo de Corte Directo indican mejores resultados a mayor contenido de cemento y mayores días de curado. / The purpose of this research is to improve the geotechnical parameters of the granular volcanic soil with the addition of Portland cement type I. First, the Granulometry test is carried out and classified by SUCS as a poorly graded sand with gravel and according to AASHTO as A-1-b. On the other hand, the Proctor test was carried out and a Maximum Dry Density of 1.21 kg/cm2 was obtained with an Optimal Moisture Content of 17.8%. In addition, the results of the Direct Shear test indicated a 33.5° friction angle, a cohesion of 0.0 kg/cm2. The second step was the Proctor test on samples with additions of 3%, 5%, 7% and 9% of cement, the optimal results were at a 5% addition. The third step, the Direct Shear test was carried out, the mixtures of 3%, 5% and 7% at 7 and 14 days of curing, the results indicated an increase of 14.6% to 79.1% in the friction angle compared to the soil natural and an increase from 25.8% to 161.5% in cut resistance. Also, the behavior of the volumetric deformation is shown, presenting a greater contraction when a normal stress of 1 kg/cm2 is applied and a greater expansion when a normal stress of 4 kg/cm2 is applied. Finally, the parameters of the Proctor test indicate the most optimal mixture with 5% and the parameters of the Direct Shear test indicate better results at higher cement content and longer curing days. / Tesis