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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
901

Ways of knowing of farmers and scientists : tree and soil management in the Ethiopian Highlands

Habermann, Birgit January 2014 (has links)
The Ethiopian Highlands have been studied extensively, hosting a large amount of research for development projects in agriculture and forestry over several decades. The encounters in these projects were also encounters of different ways of knowing that were negotiated by the actors meeting in the space provided by the projects. This research explores these encounters and the social worlds they are embedded in, drawing on actor-oriented approaches as well as theories of narratives and framing. Ways of knowing and citizen epistemologies are taken as a lens to understand the role of identities in knowledge production and use. The two case studies were agroforestry research projects in the Ethiopian Highlands. The research followed a range of qualitative and ethnographic research methods. Different types of farmers and scientists meet in the case studies. I recognise that they all have individual agency, nevertheless I use the terms ‘scientist' and ‘farmer' in this thesis. I use the terms to describe certain groups of actors who all draw on different ways of knowing, and different value systems, when interacting with each other and their environment. The results indicate that the importance of social worlds at different scales and the contexts of research projects tend to be underestimated. In spite of good intentions scientific methodologies, terminologies and narratives tend to dominate. Scientists in the case studies acknowledged the existence of farmers' ‘indigenous' knowledge, but they determined the value of knowledge by its scientific applicability and the replicability of experiments. Research systems force the scientists into a certain modus operandi with limited possibilities to experiment and to respond to the complexities and diversities of people's social worlds. Farmers in the case studies preferred observation from their parents, observing from others or the environment as a way of learning and gaining knowledge. Depending on their personalities and their life histories they also relied on alternative ways of knowing rooted in spirituality, emotions and memories. Powerful influences on ways of knowing resulted from the way languages and authority had been used. These often led to the exclusion of marginalised community members from access to knowledge and technologies. Unfortunately, common narratives prevailed in the case studies, and alternative ways of knowing were often marginalised. By acknowledging different ways of knowing and the importance of different social worlds and different ways of doing research, both scientists and farmers could benefit and develop more sustainable pathways for agricultural and forestry land use.
902

O ensino de levantamento e classifica??o de solos no curso de Engenharia Florestal do IFMT - Campus C?ceres: uma an?lise atrav?s do projeto pol?tico-pedag?gico / The teaching survey and soil classification in the course of Forestry IFMT - Campus C?ceres: an analysis by political-pedagogical project

MARCHESI, Cristiano de Souza 14 August 2013 (has links)
Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-09-26T17:50:29Z No. of bitstreams: 1 2013 - Cristiano de Souza Marchesi.pdf: 1452354 bytes, checksum: ec7728b614475bb908da89c09f1ef3eb (MD5) / Made available in DSpace on 2018-09-26T17:50:29Z (GMT). No. of bitstreams: 1 2013 - Cristiano de Souza Marchesi.pdf: 1452354 bytes, checksum: ec7728b614475bb908da89c09f1ef3eb (MD5) Previous issue date: 2013-08-14 / Despite all agricultural production leaving Brazilian soils strength of agribusiness news is that, most of the soils in the country are not classified at the appropriate level for use by the farmer, or better saying, the farms and forest, mostly not have a mapping their soils, so technically mostly producers and professionals working in these properties do not have a detailed knowledge of the types of soils that have worked. The soil classification is the basis for determining the potential use of the land, ie, guide the sustainable use of the same. For this situation, it is known that many factors corroborate the frame. Among these the human factor has great weight in this matter because, Survey and Soil Classification (LCSs) are present on curricular content for training of Agronomists, Forestry Engineers, etc.., and scholars and authorities in the field of Soil Science have signaled that the Higher Education Institutions (specifically undergraduate) come crashing in training these professionals supposedly trained and qualified to the activity of LCSs, considering that the courses that form such professionals invariably advocated among other things "solid scientific general and professional ... "what prescribes the contents of their curricular chord in the National Curriculum Guidelines. Informally today, teachers generally do mind that the problem lies in the structure of undergraduate courses regarding aspects: design of a workload of disciplines; literature indicated in ement?rios; disciplines sequence prerequisites; opportunity of additional knowledge through elective courses, etc.. Thus, sensing data bring to literature that deal with the subject, aimed this work was to analyze the conditions for teaching of LCSs course of Forestry's IFMT - Campus C?ceres through its Political-Pedagogical Project (PPP) as all the above aspects. This research is exploratory, Documentary and Quanti-qualitative nature. Included in the questionnaire data collection and content analysis for inferences. The inferences are that the references (data obtained from educators in the field of Soil Science of the five geographical regions through a questionnaire) indicate that the PPP course has limitations that may affect the teaching-learning LCSs and achieve, in this regard (themes mentioned), the professional profile designed by the course concerning "solid scientific and professional general enabling absorb and develop technology." The limitations were: inadequate sizing workload in disciplines that include LCSs and related activities; literature indicated in these ement?rio not include modern features with the potential to collaborate with a better education, sequence of disciplines inappropriate prerequisites discipline that includes these activities and, lack of opportunity for complementation of knowledge related to these themes via list of electives. Given the paucity of information in the literature that addresses on the subject, the data generated will assist both in the construction and / or reformulation of PPP courses in general as well as instigating research on the topic. / Apesar de toda produ??o agropecu?ria que saem dos solos brasileiros, pujan?a do agroneg?cio que se noticia, a maior parte dos solos do Pa?s n?o est?o classificados a n?vel adequado para utiliza??o do agricultor; ou melhor, dizendo, as propriedades agr?colas e florestais, em sua maioria, n?o possuem um mapeamento de seus solos, logo, majoritariamente produtores e profissionais tecnicamente atuantes nestas propriedades n?o possuem um conhecimento detalhado dos tipos de solos que se t?m trabalhado. A classifica??o dos solos serve de base para determina??o do potencial de uso das terras, ou seja, norteiam a utiliza??o sustent?vel das mesmas. Para esta situa??o, sabe-se que muitos fatores corroboram com o quadro. Dentre estes o fator humano tem grande peso nesta quest?o; pois, Levantamento e Classifica??o de Solos (LCSs) s?o conte?dos presentes nas matrizes curriculares para forma??o de Engenheiros Agr?nomos, Engenheiros Florestais, etc.; e, estudiosos e autoridades da ?rea de Ci?ncia do Solo t?m sinalizado que as Institui??es de Ensino Superior (especificamente cursos de gradua??o) v?m falhando na forma??o desses profissionais pressupostamente capacitados e habilitados para a atividade de LCSs; tendo em vista que, os cursos que formam tais profissionais, invariavelmente, preconizam dentre outras coisas ?s?lida forma??o cientifica e profissional geral...? daquilo que prescreve os conte?dos de suas matrizes curriculares em acorde com as Diretrizes Curriculares Nacionais. Informalmente na atualidade, docentes em geral cogitam que o problema est? na estrutura dos cursos de gradua??o quanto aos aspectos: dimensionamento de carga hor?ria de disciplinas; bibliografia indicada em ement?rios; sequencia de disciplinas pr?-requisitos; oportunidade de complementa??o de conhecimentos via disciplinas optativas, etc. Dessa forma, intuindo trazer dados ? literatura que versem sobre o assunto, objetivou-se com este trabalho analisar as condi??es para atividades de ensino de LCSs do curso de Engenharia Florestal do IFMT - Campus C?ceres atrav?s de seu Projeto Pol?tico-Pedag?gico (PPP) quanto aos aspectos supramencionados. A presente pesquisa ? Explorat?ria, Documental e de natureza Quanti-qualitativa. Incluiu o Question?rio na coleta dos dados e a An?lise de Conte?do para as infer?ncias. As infer?ncias s?o de que as refer?ncias (dados obtidos junto a educadores da ?rea de Ci?ncia do Solo das cinco regi?es geogr?ficas brasileiras atrav?s de question?rio) indicam que o PPP do curso apresenta limita??es que podem comprometer o ensino-aprendizado de LCSs e alcan?ar, neste quesito (tem?ticas mencionadas), o perfil profissional projetado pelo curso concernente a ?s?lida forma??o cient?fica e profissional geral que possibilite absorver e desenvolver tecnologia?. As limita??es encontradas foram: dimensionamento inadequado de carga hor?ria em disciplinas que contemplam LCSs e atividades correlatas; bibliografia indicada no ement?rio destas n?o incluem recursos modernos com potencial de colaborar com uma melhor forma??o; sequ?ncia inapropriada de disciplinas pr?-requisitos a disciplina que contempla estas atividades; e, inexist?ncia de oportunidade para complementa??o dos conhecimentos relacionados a tais tem?ticas via rol de disciplinas optativas. Dado a escassez de informa??es na literatura que trate sobre o assunto, os dados gerados poder?o auxiliar tanto na constru??o e/ou reformula??o de PPP de cursos em geral bem como instigar pesquisas sobre a tem?tica.
903

HYDROLOGIC MONITORING AND 2-D ELECTRICAL RESISTIVITY IMAGING FOR JOINT GEOPHYSICAL AND GEOTECHNICAL CHARACTERIZATION OF SHALLOW COLLUVIAL LANDSLIDES

Crawford, Matthew M. 01 January 2018 (has links)
Landslide characterization and hazard assessments require multidisciplinary approaches that connect geologic processes with geotechnical parameters. Field monitoring of hydrologic variables such as water content and water potential, coupled with geoelectrical measurements that can establish relationships used for geotechnical and landslide hazard investigations is deficient. This study brings together different techniques to develop a methodology that connects geoelectrical measurements and shear strength. A field-based framework was established that includes (1) analysis of long-term soil moisture fluctuations within different landslides (2) establishment of constitutive and new equations that test the use of electrical conductivity to predict soil-water relationships and shear strength (3) using electrical resistivity tomography (ERT) to support and facilitate the prediction of shear strength in a slope. Hydrologic conditions including volumetric water content, water potential, and electrical conductivity in the soil were measured at three active landslides in Kentucky. The in-situ electrical conductivity used within the framework is valid as a predictor of suction stress and shear strength. The ERT supports interpretations of landslide failure zones, landslide type, lithologic boundaries, and changes in moisture conditions, but also is able to utilize the methodology to calculate shear strength, and provide a spatial view of shear strength in the slope. The practical application of this framework is to support landslide hazard assessment and further understand the long-term influence of moisture conditions in hillslope soils. These parameters are pertinent to investigating the stability of landslides that are often triggered or reactivated by rainfall.
904

EXPLORING SPATIAL AND TEMPORAL VARIABILITY OF SOIL AND CROP PROCESSES FOR IRRIGATION MANAGEMENT

Reyes, Javier 01 January 2018 (has links)
Irrigation needs to be applied to soils in relatively humid regions such as western Kentucky to supply water for crop uptake to optimize and stabilize yields. Characterization of soil and crop variability at the field scale is needed to apply site specific management and to optimize water application. The objective of this work is to propose a characterization and modeling of soil and crop processes to improve irrigation management. Through an analysis of spatial and temporal behavior of soil and crop variables the variability in the field was identified. Integrative analysis of soil, crop, proximal and remote sensing data was utilized. A set of direct and indirect measurements that included soil texture, electrical conductivity (EC), soil chemical properties (pH, organic matter, N, P, K, Ca, Mg and Zn), NDVI, topographic variables, were measured in a silty loam soil near Princeton, Kentucky. Maps of measured properties were developed using kriging, and cokriging. Different approaches and two cluster methods (FANNY and CLARA) with selected variables were applied to identify management zones. Optimal scenarios were achieved with dividing the entire field into 2 or 3 areas. Spatial variability in the field is strongly influenced by topography and clay content. Using Root Zone Water Quality Model 2.0 (RZWQM), soil water tension was modeled and predicted at different zones based on the previous delineated zones. Soil water tension was measured at three depths (20, 40 and 60 cm) during different seasons (20016 and 2017) under wheat and corn. Temporal variations in soil water were driven mainly by precipitation but the behavior is different among management zones. The zone with higher clay content tends to dry out faster between rainfall events and reveals higher fluctuations in water tension even at greater depth. The other zones are more stable at the lower depth and share more similarities in their cyclic patterns. The model predictions were satisfactory in the surface layer but the accuracy decreased in deeper layers. A study of clay mineralogy was performed to explore field spatial differences based on the map classification. kaolinite, vermiculite, HIV and smectite are among the identified minerals. The clayey area presents higher quantity of some of the clay minerals. All these results show the ability to identify and characterize the field spatial variability, combining easily obtainable data under realistic farm conditions. This information can be utilized to manage resources more effectively through site specific application.
905

EFFECTS OF DEPOSITIONAL PROCESSES ON STRENGTH AND COMPRESSIBILITY OF SEDIMENTS USING ELASTIC SHEAR WAVE VELOCITY

Muttashar, Wisam Razzaq 01 January 2019 (has links)
Depositional processes are the most critical, complicated conditions that govern sediment properties and their variations, which in turn significantly affect the geotechnical behavior of the sediment. The complexity of depositional and post-depositional processes, which results in a variety of depositional environments, makes constructing a plausible model for the consolidation process of sediments difficult. The mutual influence between the temporal and spatial variation of depositional environments with their resultant physical and mechanical properties cause several compression issues, such as consolidation settlement and land subsidence, which mostly occur in estuarine-riverine regions throughout the world. The first aim of this study is proposing a new grain-size based scheme to classify unconsolidated inorganic sediments that cover a wide range of natural depositional environments with a special emphasis on fine-grained deposits. The proposed classification depends on the linear relationship between percent Fines and the silt fraction. By combining grain size characteristics and plasticity, the proposed scheme provides further characterization of depositional environments. The proposed scheme extends the utility of the scheme beyond simply classifying the sediment class, towards inferring the potential mechanical behavior of sediments having various Grain Size Distribution (GSD) proportions and mineralogy. Addressing elastic wave properties as a geotechnical parameter, in particular, shear wave velocities to determine the mechanical behavior of sediments is because is strongly influenced by the change in those physical state properties during compression and cementation processes. This study presents a continuous function that explicitly uses shear wave velocity to predict the non-linear function of consolidation process (e -log p'), This approach also defines factors that describe the depositional environment, such as grain size and plasticity limits. These factors are shown to influence and control the e -log p' relationship. Thus, the resulting function is shown to be applicable to a variety of sedimentary materials. Also, in this dissertation, elastic shear-wave velocity under critical state framework was employed. A shear wave-based constitutive model was developed that is able to predict the stress-strain behavior of a normally consolidated sediments, under undrained loading. A new power-type relationship that predicts the shear strength behavior and critical stress paths of fine-grained sediments under undrained conditions. Also, it investigates the reliability of the link between input model parameters with the basic properties of a variety of fine-grained sediments. As importance of measuring of elastic wave velocities, a number of soil tests performed during particular construction stages can be reduced and compensated. This reduces the cost of evaluating the stability level, monitoring stress path distributions, and determining undrained shear strength behavior during particular stages of the construction process. The study also provides correlations that can be applied in various fine-grained depositional environments that have weak, fine-grained soil layers, on which the constructions are built.
906

SPATIAL ESTIMATION OF HYDRAULIC PROPERTIES IN STRUCTURED SOILS AT THE FIELD SCALE

Zhang, Xi 01 January 2019 (has links)
Improving agricultural water management is important for conserving water during dry seasons, using limited water resources in the most efficient way, and minimizing environmental risks (e.g., leaching, surface runoff). The understanding of water movement in different zones of agricultural production fields is crucial to developing an effective irrigation strategy. This work centered on optimizing field water management by characterizing the spatial patterns of soil hydraulic properties. Soil hydraulic conductivity was measured across different zones in a farmer’s field, and its spatial variability was investigated by using geostatistical techniques. Since direct measurement of hydraulic conductivity is time-consuming and arduous, pedo-transfer functions (PTFs) have been developed to estimate hydraulic conductivity indirectly through more easily measurable soil properties. Due to ignoring soil structural information and spatial covariance between soil variables, PTFs often perform unsatisfactorily when field-scale estimations of hydraulic conductivity are needed. The performance of PTFs in estimating hydraulic conductivity in the field was therefore critically evaluated. Due to the presence of structural macro-pores, saturated hydraulic conductivity (Ks) showed high spatial heterogeneity, and this variability was not captured by texture-dominated PTF estimates. However, the general spatial pattern of near-saturated hydraulic conductivity can still be reasonably generated by PTF estimates. Therefore, the hydraulic conductivity maps based on PTF estimates should be evaluated carefully and handled with caution. Recognizing the significant contribution of macro-pores to saturated water flow, PTFs were further improved by including soil macro-porosity and were proven to perform much better in estimating Ks compared with established PTFs tested in this study. Additionally, the spatial relationship between hydraulic conductivity and its potential influencing factors were further quantified by the state-space approach. State-space models outperformed current PTFs and effectively described the spatial characteristics of hydraulic conductivity in the studied field. These findings provided a basis for modeling water/solute transport in the vadose zone, and sitespecific water management.
907

LONG-TERM LAND MANAGEMENT PRACTICES AND THEIR EFFECT ON SOIL HEALTH AND CROP PRODUCTIVITY

Muratore, Thomas Joseph, Jr. 01 January 2019 (has links)
Agricultural intensification reliant on monocrops could change soil health in a way that does not support maximum crop productivity. Twenty-nine-year-old no-till field plots at the University of Kentucky Spindletop research farm showed a significant reduction in corn yields from continuous corn plots compared to those from plots in various types of rotation. The objective of this study was to determine what role soil microbes might play in yield reduction and how management and time effects microbial community structure. Samples were collected from the following treatments: continuous corn (CC), continuous soybean (SS), a 2-year corn/soybean rotation (CCSS), Corn in rotation with soybean with winter wheat cover (C/W/S), and sod controls (SOD). Soil health-related parameters were determined along with microbial community structure using phospholipid fatty acid analysis (PLFA). Results show that there is a strong seasonal dynamic in microbial communities with May, July and September showing the greatest differentiation between treatments. Nonparametric multidimensional analysis (NMDS) shows that microbial communities under SS, CC treatments were significantly different from the CS and CWS treatments across all four years of the study. My findings will prove useful for assessing the contribution of biological indicators to agroecosystem function and will aid in making recommendations of when and how to manage these parameters to improve soil health and maximize yield.
908

Laboratory Evaluation of Recycled Crushed Glass Cullet for Use as an Aggregate in Beach Nourishment and Marsh Creation Projects in Southeastern Louisiana

Wildman, John C 20 December 2018 (has links)
To combat the rapid degradation of the Louisiana coast, the Louisiana Coastal Protection and Restoration Authority has planned strategic land building initiatives throughout the Louisiana Gulf coast, including beach nourishment and marsh creation projects. It is commonly agreed that the state lacks sufficient renewable sediment resources to maintain the planned CPRA land building program. However, Louisiana, the state that commonly ranks last in state recycling percentage, recycles an estimated 0.6% of the waste glass consumed in the state. Glass is predominantly silica sand. This thesis evaluates laboratory‑determined characteristics of recycled crushed glass cullet to assess its suitability as a renewable aggregate for beach nourishment and marsh creation projects. Specifically, the research herein evaluates geotechnical and settling characteristics of recycled crushed glass cullet produced in Pearl River, Louisiana. Additionally, this research evaluates the effects on beach nourishment and marsh creation design parameters of blending this material with Gulf coastal sediments.
909

Environmental Assessment of Arsenic and Mercury Levels at the Garfield Mill Site, Calico, California

Thorp, Steven Gregory 01 September 2019 (has links)
Environmental impacts of mining at Calico, California, are poorly understood in comparison to the details of its history of silver production. Human health risks associated with arsenic from the lode rock, as well as mercury from the silver milling process, include central nervous system damage, organ failure, and death. To quantify the potential human health risk and manage remediation of this site, tailings from the Garfield Mill site were digitally mapped and chemically analyzed by portable x-ray fluorescence, which permitted volumetric estimates of total mill tailings and the arsenic and mercury budget, as well as identification of anomalies in the distribution of these elements within the tailings deposit. Final products include a high-resolution digital orthomosaic map showing the extent of the tailings deposit, giving contours of arsenic and mercury distribution and identifying areas of high concern for future remediation. The information gathered during this study will be of immense use to the city of Barstow, providing a basis for future public health studies and assessments of human health risks in the area.
910

Arsenic in the Soils of Northwest Oregon

Ricker, Tracy Ryan 26 February 2013 (has links)
One hundred and eighty-six soil samples from Northwest Oregon were tested for arsenic content. The highest values measured were 13.9 ppm in the A horizon (site C4) and 20.4 ppm in the B horizon (Site P4). Arsenic was not detected in 28 A horizon samples and 23 B horizon samples. Data are grouped based on the age and rock type of underlying bedrock. Lithologic groups with six or more data points were compared statistically to ascertain if groups are distinct. Analysis of Variance (ANOVA) multiple comparison tests indicate that the arsenic content of the Marine Sediments and Sedimentary Rocks group samples is distinguishable from the Quaternary Basalts group in the A horizon and all other groups in the B horizon. Kruskal-Wallis multiple comparison tests indicate that the arsenic content of the Marine Sediments and Sedimentary Rocks group is distinguishable from the Quaternary Basalts, Quaternary/ Tertiary Sediments and Sedimentary Rocks and Volcanic Sediments groups in both the A and B soil horizons. The ANOVA and Kruskal-Wallis tests compared A and B horizon data by lithologic group. The ANOVA shows the Marine Sediments and Sedimentary Rocks group in the A horizon is distinct from the Quaternary Basalts in the A and B horizon. The Kruskal-Wallis test yielded the same result. Per the ANOVA, the Marine Sediments and Sedimentary Rocks in the B horizon are distinct from all other tested groups. The Kruskal-Wallis test shows the Marine Sediments and Sedimentary Rocks group in the B horizon as distinct from the Quaternary Basalts, Quaternary/ Tertiary Sediments, and Volcanic Sediments groups in the A and B horizon. A K-means cluster analysis was used to group all available data independent of underlying bedrock. Three, four, and five group analyses were conducted, and the results of these tests were compared to the data grouped by underlying rock type. No correlation between the groups resulting from the K-means cluster analysis and groups based on underlying lithology was found. This analysis supports the creation of a map distinguishing arsenic content in the soils above Marine Sediments and Sedimentary Rocks group units from arsenic content in all other tested lithologic groups. The mean and standard deviations of these groups (in ppm) are: A horizon: Marine Sediments (6.09 ±2.66); other groups (3.10 ±3.19); B horizon: Marine Sediments (10.26 ±4.65); other groups (3.13, ±2.52). This analysis indicates that geologic context must be taken into account when determining background levels of naturally occurring arsenic in soils.

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