Dissertations / Theses on the topic 'Soils and climate Australia'
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Grover, Samantha Patricia Power, and samgrover1@gmail com. "Carbon and water dynamics of peat soils in the Australian Alps." La Trobe University. Centre for Applied Alpine Ecology, School of Life Sciences, 2006. http://www.lib.latrobe.edu.au./thesis/public/adt-LTU20070627.172842.
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This research investigated carbon dynamics, water dynamics and peat formation at
Wellington Plain peatland in the Victorian Alps. The properties of bog peat and dried
peat were measured, and the ensuing results are outlined below.
The carbon chemistries of both bog peat and dried peat displayed changes with
depth consistent with an increase in the extent of decomposition of the organic
material. Representative changes in the alkyl:O-alkyl ratio down the profile were
0.14 to 0.96 for bog peat and 0.28 to 1.07 for dried peat. Laboratory incubations on
the influence of chemistry, particle size, water content and sample preparation
indicated that, in the absence of confounding factors, peat chemistry was the most
important factor in determining the size of the mineralisable carbon pool. Water
content was the most important factor in determining the rate of carbon
mineralization. In the field, both bog peat and dried peat emitted an average of
2 g CO2/m2/d from the surface. Carbon mineralisation was related to both soil
temperature and soil water content, and this relationship was used to model peat
mineralisation under a range of possible future climate scenarios. Below the surface,
however, I measured lower rates of decomposition in the dried peat than in the bog
peat.
The water-holding capacity of peat was measured in the laboratory, as was the
rate of water movement through peat. Specific yield decreased down the profile in
both bog peat (0.88 to 0.45 cm3/cm3) and dried peat (0.36 to 0.11 cm3/cm3). Hydraulic
conductivity also decreased down the profile in both peats: 5.1x10-4 to 3.0x10-6 m/s in
bog peat, and 1.0x10-4 to 7.0x10-6 m/s in dried peat. Relationships between the
hydrologic properties of peat and its physical and chemical properties were identified.
In the field, fluctuations in the watertable were monitored in concert with rainfall.
These laboratory and field measurements enabled me to develop models of the
hydrology of bog peat and dried peat.
Radioisotope dating indicated that both bog peat and dried peat began forming
around 3300 years ago. The bog peat appeared to have drained to form dried peat
between 131 and 139 years ago. Since that time, erosion appeared to have contributed
more to the loss of organic material from dried peat than carbon mineralisation had.
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Tiver, Fleur. "Vegetation patterns of eastern South Australia : edaphic control and effects of herbivory /." Title page, contents and abstract only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09pht623.pdf.
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Grevenitz, Paul. "The character and genesis of pedogenic calcrete in southern Australia." Access electronically, 2006. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20061206.141643/index.html.
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Farhoodi, Alireza. "Lime requirement in acidifying cropping soils in South Australia." Title page, table of contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phf223.pdf.
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"August 2002" Bibliography: leaves 230-254. Field sites and soils from cropping studies in the mid-north of South Australia were used to address questions of soil responses to lime and the influence of acidifying inputs. The study showed that LMWOAs associated with different stubbles can help to ameliorate toxicity through complexation with A1.
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Hardiputra, Bingah Astuti. "Properties of rehabilitated coalmine soils at Collie." University of Western Australia. Soil Science and Plant Nutrition Discipline Group, 2004. http://theses.library.uwa.edu.au/adt-WU2005.0041.
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[Truncated abstract] Many soil properties are involved in supporting the growth of plants and in limiting soil degradation. The present study was carried out to provide a basis for minimising environmental impact by providing a firm understanding of the soil properties that affect plant growth for soils developed from mining waste from the Wesfarmers Premier coalmine at Collie. The purpose of this study was to provide an understanding of the soil materials and to identify the potential interactions between soil properties and plants for soils developed on coalmine materials at the Premier mine, Collie. This research was to identify the nature of the manmade soils so as to determine if soil forming processes are active, to determine soil acidity including pH buffering capacity and the lime requirement of soils, to measure water retention characteristics and soil available water for plant growth, to relate soil properties to possible effects on plant growth, and to identify management strategies to improve soil conditions and overcome plant growth constraints. Seventy-seven manmade horizons from pits in 18 constructed soils, ranging from 9 to 21-years old, were analyzed throughout this study. These samples are classified based on soil depth, layer (topsoil and subsoil), and age of soil since rehabilitation. The methods for doing most of the analyses follow the Australian Soil and Land Survey handbook by Rayment and Higginson (1992). The results are presented quantitatively and soil properties are compared to provide information on pedogenic processes, the extent of soil development, the ability of the soils to resist degradation and to provide an indication of soil parent materials
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Fotovat, Amir. "Chemistry of indigenous Zn and Cu in the soil-water system : alkaline sodic and acidic soils." Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phf761.pdf.
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Copies of author's previously published articles inserted. Bibliography: leaves 195-230. In this study the soil aqueous phase chemistry of Zn and Cu in alkaline sodic soils are investigated. The chemistry of trace metal ions at indigenous concentrations in alkaline sodic soils are reported. Metal ions at low concentrations are measured by the graphite furnace atomic absorption spectrometry (GFAAS) technique.
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Morey, Bethany. "Organic profiling of Western Australia soils for provenance determination." Thesis, Morey, Bethany (2018) Organic profiling of Western Australia soils for provenance determination. Honours thesis, Murdoch University, 2018. https://researchrepository.murdoch.edu.au/id/eprint/41698/.
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In Western Australia, the Swan Coastal Plain encompasses the majority of the Perth metropolitan region and hence is often the site of forensic investigations. Due to the similarity in the geology and associated mineralogical profiles of the area, analysis of organic components of soil recovered from items of interest may provide greater discriminatory power when attempting to determine provenance. Identification of plant waxes has been used previously in the United Kingdom to discriminate between soils derived from garden beds; however, the wider applicability of the technique, particularly for soils low in organic matter, such as those present within the Swan Coastal Plain in Perth, Western Australia, has not been demonstrated.
The efficiencies of two methods were compared to assess their suitability for the extraction of plant wax compounds in Perth Metropolitan soils. Soxhlet extraction was found as the more accurate method when compared with the alternative liquid-liquid extraction. The development of the Soxhlet methodology enabled the extraction of alkanes and fatty acids from a 2.5 g soil sample.
Soil samples were collected within a series of North-South and East-West lines within the Bassendean and Spearwood Dune systems of the Swan Coastal Plain (n=19) to represent a small sample of differing soils provenances and enabled the investigation of the between-site variation. Samples were subjected to Soxhlet extraction for 24h, and the alkanes and fatty acids present in the extracts were analysed using GC-MS. Qualitative analysis (n=8) of combined alkane and fatty acid profiles provided a preliminary understanding of the differences that may occur between sample sites as a result of the surrounding botanical influences. Quantitative analysis (n=11) revealed that the combined alkane and fatty acid profiles enabled the discrimination between the soil sites (R = 0.873 p = 0.001). The results of this study indicate the potential for the organic profiling of soils with low organic content at a scale relevant to forensic investigations.
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Odell, Simon Paul. "Microbial reclamation of alkaline sodic soils /." Title page, contents and abstract only, 2000. http://web4.library.adelaide.edu.au/theses/09ASOP/09asopo23.pdf.
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Williams, Allyson. "Climate change in the Southwest of Western Australia." Thesis, Williams, Allyson (1991) Climate change in the Southwest of Western Australia. Honours thesis, Murdoch University, 1991. https://researchrepository.murdoch.edu.au/id/eprint/41550/.
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Previous studies in the southwest of Western Australia suggest a trend of decreasing rainfall in both a spatial and temporal sense. What are the primary influences of this climatic change?
This analysis is a four step process involving examining the spatial distribution of rainfall, determining the major influences of the climate, determining what spatial and temporal changes have occurred, and explain possible causes of these changes.
Climatic data for winter and summer seasons and,.over four time periods (1900-45, 1946-90, 1946-68, 1968-90) is examined at thirtyfive stations in the southwest for any longterm trends, their degree of statistical significance, and how they relate to widespread climate change and regional changes. Of special interest here is the possible effect a rapid, large scale change of vegetation has on the precipitation of this region.
For the period 1946-90 the winter rainfall is decreasing along the west and south coasts. The trends are as predicted by the proposed Greenhouse effect. However the high degree of natural variability of climate data is reinforced with trends being within the scope of the natural fluctuations.
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Barnuud, Nyamdorj Namjildorj. "Determining climate change impacts on viticulture in Western Australia." Thesis, Curtin University, 2012. http://hdl.handle.net/20.500.11937/1677.
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Global climate model simulations indicate 1.3°C to 1.8°C increase in the Earth’s average temperature by middle of this century above the 1980 to 1999 average. The magnitude and rate of change of this projected warming is greater than the average warming during the last century. Global climate models project an even higher degree of warming later in the century also due to increasing grrenhouse gases concentrations in the atmosphere from human activity. Impacts of future climate change on viticulture are likely to be significant as viticulture requires a narrow climate range to produce grapes of suitable quality for premium wine production.In this thesis, impacts of climate change on winegrape growing conditions across the Western Australian wine regions were spatially and temporally examined by utilising fine resolution downscaled climate projections. Relationships between climate variation and grape maturity or key quality attributes of Cabernet Sauvignon, Shiraz and Chardonnay were modelled from measured fruit and climate data along a natural climate gradient encompassing a 5°C range in winegrape growing season average temperature. Potential future climate change impacts on grape quality were quantitatively evaluated by driving the grape quality models with the downscaled climate projections.Analyses of climate conditions for winegrape growth were carried out under future climate projections for the Western Australian wine regions. A total of 10 global climate models forced with an A2 emission scenario were downscaled. Of these models, the MEDRES Miroc3.2 and CSIRO Mk3.5 climate models, which indicated the low and high warming ranges (projections of these models will be referred as low and high range warming, hereafter) across the study regions, were selected to take into account the uncertainty of future climate change for impact assessment. Our results indicate increasingly warmer and drier climate conditions for the Western Australian wine regions. The current October to April average temperature (averaged across the regions) is projected to be 0.5°C to 1.5°C warmer by 2030, respectively. The magnitude of the warming will likely be uneven across the regions. For example, 0.1 to 0.3°C higher average temperature during October to April period has been projected for the northern regions than the southern regions by 2030, depending on the warming ranges. On the other hand, rainfall is projected to decrease across the regions under the future scenario we assessed in this study. By 2030, annual rainfall, averaged across the regions, is projected to decline by 5 to 8%, respectively, under the low and high warming ranges of climate change under the A2 emission scenario. Among seasons, the greatest decline in rainfall is projected to occur during spring. On average, up to 8% and 19% decline in spring rainfall is projected respectively under the low and high warming ranges by 2030.The magnitude of these changes are projected to increase as time progresses. For example, by 2070, averaged across the study regions, our modelling results show current mean temperature during October to April is projected to be between 1.1°C and 3.9°C warmer, but the annual rainfall is likely to be 15 to 24% lower than the current climate averages (1975 to 2005) under the A2 scenario.Maturity dates of the studied varieties are projected to advance asymmetrically across the study regions. For example, Cabernet Sauvignon may reach 22 °Brix total soluble solid maturity about 4 and 7 days earlier respectively for the northern and the southern regions by 2030 under the low warming range. Our results also indicate maturity date shifting a further 8 and 18 days earlier by 2070 for the northern and the southern regions respectively under the same warming range. Patterns of this maturity date shifting is likely to be similar under the high warming range. However, the magnitude of advancement is projected to be doubled.If no adaptive measures are implemented future climate change will likely reduce wine quality due to declining concentrations of berry anthocyanins and acidity under a warmer climate. The reductions of berry quality attributes are likely to be more pronounced in the warmer northern wine regions compared to the cooler southern regions. For example, Cabernet Sauvignon current median anthocyanins concentration is projected to decline by about 12% and 33% for the warmer northern regions, and about 6 to 18% for the cooler southern wine regions respectively by 2030 and 2070 under the high warming range. In contrast, the maximum decline in Cabernet Sauvignon anthocyanin concentration under the lower warming range is projected to be small, up to 5% for the cooler southern and up to 8% for the warmer northern regions by 2070. Shiraz anthocyanins concentration decrease pattern is similar to that of Cabernet Sauvignon, however, our modelling indicates the magnitude is smaller, with maximum of 18% for Swan District and about 11% for the southern regions by 2070 under the high warming range.Modelled impacts of climate change on grape titratable acidity are also region and variety specific. Among the varieties studied, Chardonnay exhibits the highest decline in median titratable acidity across the regions (17% for the Margaret River and 42% for the Swan District regions), followed by Shiraz (7% for the Margaret River and 15% for the Peel regions) and Cabernet Sauvignon (no change for Blackwood and 12% for the Swan District regions) by 2070 under high climate warming. On the other hand, the median titratable acidity levels are less impacted by low warming scenario (maximum decline is 4% for Shiraz only by 2070).Under the future warming scenarios studied in this thesis currently established wine regions and wine styles across the Western Australian wine regions are likely to be affected to the extent that some regions may not be conducive to premium wine production, while for some regions changing the variety may be the only option to adapt to the climate change. For example, by 2070, under high warming range Swan District, Perth Hills, and some parts of the Peel and Geographe regions are projected to be suited more to producing fortified wines or table grapes due to high average growing season temperature (>24°C). In this future climate the present cool climate southern regions are likely to have the same climate conditions that currently prevail in the warmer Swan District. Apparent differences in currently planted varieties between the cooler southern and warmer northern regions clearly indicate the need to adapt to the warming climate in the southern wine regions.Analysis of other potential factors that influence viticulture such as frequency of hot days, vapour pressure deficit and disease pressure were examined. The results indicated that winegrape fungal disease pressure will likely decrease across the regions due to the declining rainfall, potentially lessening the need for spraying during the growing season. On the other hand, there will likely be increased frequency of hot days and elevated vapour pressure deficit. The impacts of these, combined with the decreasing rainfall during growing season will potentially drive irrigation demand higher requiring altered water management under climate change.Climatically, most of the Western Australian wine regions are known as premium wine producing areas. The results from this study indicate potential challenges of climate change for the Western Australian wine industry. Under the future climate scenarios examined, some currently warmer regions may become less suitable for premium quality wines due to the increased temperature, which is projected to be out of the optimum temperature range for premium wine production. For most of the other regions, the challenge will likely be a decreased grape quality required to produce premium wine with the current varieties. Suitable adaptation strategies may be required to maintain the current market reputation. Furthermore, the warmer and drier conditions under climate change is likely to necessitate revised water management across the wine growing regions, especially some regions which are already limited by available water for grape production. However, the magnitude of the impacts is projected to be dependent upon the magnitude of future climate change.
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Sarmah, Ajit K. "Persistence and mobility of triasulfuron, metsulfuronmethyl, and chlorsulfuron in alkaline soils." Title page, abstract and contents only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phs2461.pdf.
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Bibliography: leaves 157-174. This study examined the fate of three common sulfonylurea herbicides in highly alkaline soils through a series of laboratory and field experiments to determine if existing leaching models could be used to describe their field behaviour under Australian climatic conditions. A liquid chromatographic method was developed to simultaneously determine levels of triasulfuron, metsulfuronmethyl, and chlorsulfuron in soil and water. The investigation of base hydrolysis for the herbicides in aqueous buffer and soil solutions determined that it was unlikely to be a major loss pathway for sulfonylureas in alkaline soils. The herbicides were found to have low sorption, very little retardation and high mobility, moving at a marginally slower rate than water. Degradation did not follow first-order kinetics, but rather a two-stage process appeared to be involved. Both VARLEACH and LEACHM models predicted the measured concentration of the herbicides reasonably well in profile under low rainfall conditions but were less adequate under high rainfall. Forecasts with the LEACHP model predicted levels of the herbicides for a dominant soil type of the cereal belt of southern Australia with median rainfall after a year.
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Chorom, Mostafa. "Behaviour of alkaline sodic soils and clays as influenced by pH and particle change." Title page, contents and abstract only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phc551.pdf.
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Copies of author's previously published articles inserted. Bibliography: leaves 173-196. The objective of this thesis is to investigate the factors affecting swelling and dispersion of alkaline sodic soils containing lime and the ways to manage these soils to improve their physical condition. Studies on pure clay systems are included to understand the fundamental process involved in swelling and dispersion of pure and soil clays.
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Davies, Beresford O. A. "A model for the prediction of subgrade soil resilient modulus for flexible-pavement design : influence of moisture content and climate change /." See Full Text at OhioLINK ETD Center (Requires Adobe Acrobat Reader for viewing), 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1102690606.
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Thesis (M.S.V.)--University of Toledo, 2004.Typescript. "A thesis [submitted] as partial fulfillment of the requirements of the Master of Science degree in Civil Engineering." Bibliography: leaves 80-83.
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Grieger, Gayle. "The effect of mineralogy and exchangeable magnesium on the dispersive behaviour of weakly sodic soils /." Title page, table of contents and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phg8478.pdf.
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Marquès, Bueno Montserrat. "Climate change impact on the photodegradation of polycyclic aromatic hydrocarbons in soils." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/440515.
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Les avaluacions del Panell Intergovernamental del Canvi Climàtic han evidenciat que l’augment d’emissions amb efecte hivernacle ha causat que el clima canviï més ràpidament. Encara que s’espera un impacte a escala global, les regions més septentrionals del planeta, juntament amb la zona mediterrània, són àrees especialment vulnerables. L’increment de la temperatura i la radiació UV-B alterarà el comportament de nombrosos contaminants, com per exemple els hidrocarburs aromàtics policíclics (HAPs). Per tant, aquests contaminants són potencialment vulnerables al canvi climàtic. L’objectiu d’aquesta tesi doctoral és l’avaluació de l’impacte de la temperatura i la intensitat de la llum en el comportament dels HAPs en sòls mediterranis. S’analitzaren a nivell de laboratori les variacions en les concentracions dels 16 HAPs de la US EPA en sòls, juntament amb l’impacte ecotoxicològic i la identificació de subproductes de la fotodegradació. Es van comparar les condicions climàtiques actuals i les de l’escenari de canvi climàtic extrem RCP8.5 segons previsions de l’IPCC per la regió mediterrània. Els resultats van demostrar que la dinàmica dels HAPs és regulada per les propietats fisicoquímiques de cada HAP, la temperatura, la intensitat de la llum i la textura del sòl. Aquest experiment també es va dur a terme sota l’efecte de la radiació solar, fet que va afavorir la fotodegradació dels HAPs en comparació amb l’experiment previ a nivell de laboratori. L’augment de la temperatura i la intensitat de la llum també va provocar que es formessin més subproductes de la fotodegradació, com oxi- i nitro- HAPs. Aquests derivats són més tòxics que els propis HAPs, de manera que l’impacte del canvi climàtic podria ser dramàtic pels ecosistemes i la salut humana.Las evaluaciones del Panel Intergubernamental del Cambio Climático han evidenciado que el aumento de emisiones con efecto invernadero ha provocado que el clima cambie más rápidamente. Aunque se espera un impacto a escala global, las regiones más septentrionales del planeta, juntamente con la zona Mediterránea, son áreas especialmente vulnerables. El incremento de la temperatura y la radiación UV-B alterará el comportamiento de numerosos contaminantes, como por ejemplo los hidrocarburos aromáticos policíclicos (HAPs). Por lo tanto, estos contaminantes son potencialmente vulnerables al cambio climático. El objetivo de esta tesis doctoral era llevar a cabo la evaluación del impacto de la temperatura y la intensidad de la luz en el comportamiento de los HAPs en suelos Mediterráneos. Se analizaron a nivel de laboratorio las variaciones en las concentraciones de los 16 HAPs de la US EPA en suelos, juntamente con el impacto ecotoxicológico y la identificación de subproductos de la fotodegradación. Se compararon las condiciones climáticas actuales y las del escenario de cambio climático extremo RCP8.5 según proyecciones del IPCC para la región Mediterránea. Los resultados demostraron que la dinámica de los HAPs está regulada por las propiedades físicoquimicas de cada HAP, la temperatura, la intensidad de la luz y la textura del suelo. Este experimento también se llevó a cabo bajo el efecto de la radiación solar, hecho que favoreció la fotodegradación de los HAPs en comparación con el experimento previo a escala de laboratorio. El aumento de la temperatura y la intensidad de la luz también causaron la formación de más subproductos de la fotodegradación, como oxi- y nitro- HAPs. Estos derivados son más tóxicos que los propios HAPs, de forma que el impacto del cambio climático podría ser dramático para los ecosistemas y la salud humana.
The Intergovernmental Panel on Climate Change (IPCC) assessments have evidenced that the Earth’s climate is changing faster, because of an increasing emission of greenhouse gases. Although a global impact is expected, high latitude and Mediterranean regions are especially vulnerable areas. The increase of temperature and UV-B radiation will alter the fate and behavior of a wide range of pollutants, such as polycyclic aromatic hydrocarbons (PAHs). Therefore, these pollutants are potentially vulnerable to the climate change. This PhD thesis was aimed at evaluating the impact of temperature and light intensity on the fate of PAHs in Mediterranean soils. Concentration changes of the 16 US EPA priority PAHs in soils, its ecotoxicological impact, and the identification of photodegradation by-products, were experimentally conducted at lab scale by comparing current environmental conditions and the IPCC RCP8.5 climate change scenario, for the Mediterranean region. Physicochemical properties of each individual PAH, temperature, light intensity and soil texture were identified as key factors regulating the PAH dynamics. The experiment was also conducted under solar radiation, which significantly enhanced the PAH photodegradation in comparison to values at lab scale. An increase of PAH photodegradation by-products, such as oxy- and nitro-PAHs, was also detected in soils subject to high temperature and light intensity. Because these new substances might be more toxic than parental compounds, the impact of climate change may be dramatic for the ecosystems and the human health.
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Gärdenäs, Annemieke. "Soil organic matter in forest soils : effects of climate and water balance /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1998. http://epsilon.slu.se/avh/1998/91-576-5530-8.gif.
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Ashton, Nicola Jane. "Holistic characterisation of soils developed on contrasting lithologies, in a temperate climate." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/holistic-characterisation-of-soils-developed-on-contrasting-lithologies-in-a-temperate-climate(3e0b006c-60f5-4814-8f2a-101c2b9c7bba).html.
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The influence of parent lithology on the development of soil biogeochemical environments and their microbial diversity is explored by characterising soil profiles with respect to their mineral, solution and organic chemistry. Soil profiles were collected from a total of 17 sites, above basalt, granodiorite, shale, sandstone and limestone, across Northern Ireland. The soil system developed above basalt was examined to assess the development of soil bio-physicochemical properties and microbial diversity through the profile. These basalt soils showed two distinct horizons have developed in the previous 15’000 years, where soils from the top 20 cm of the profile were highly influenced by the interactions of soil minerals with soil organic and biological processes. In line with the observed differences in soil properties the microbial community structure varied; in the surface soils the community composition was dominated by root-associated bacteria. However the relative abundance of phyla affiliated with nutrient-limited conditions increased in samples from the base of the profile. Detailed examination of the soil profiles above granodiorite, shale, sandstone and limestone revealed large variations in soil geochemistry between profiles, reflecting the mineral geochemistry of the parent rock. Molecular analysis of SOM revealed compositional changes with depth were comparable between profiles; however TOC concentrations were consistently higher in the soil profiles above basalt suggesting greater stabilisation of SOM in these soils. The chemistry of the soil waters was not reflective of the parent rocks; however variations in soil texture, specifically the abundance of less reactive residual minerals in the sandstone and limestone soils, led to higher concentrations of soluble elements in these soils. Soil pH and DOC were found to have a large control on buffering the release of free Al, Cr and Fe ions into solution. The microbial communities in near-surface soils were similar to each other, regardless of lithology, and were dominated by Proteobacteria, Actinobacteria, and Acidobacteria. However microbial diversity shifted with depth; the abundance of Actinobacteria decreased and Nitrospirae increased, and between rock types where soils next to the basalt, shale and granodiorite bedrock contained sequences affiliated with novel Candidate Phyla AD3 and GAL15. In these soils differences in SOM composition were the main driver of the observed variation with depth, however where labile SOM was depleted, mineral and solution geochemistry may have a larger control on the community composition. To assess the influence of parent lithology on selenium mobility, soils above basalt and granodiorite were amended with sodium selenate. Under anaerobic conditions, the proportion of soluble selenate removed varied (39-77 %) depending on the sample through a combination of abiotic and microbial reduction processes. However, under aerobic conditions, larger concentrations of selenate remained in solution (79-100%).
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Nuruzzaman, Mohammad. "Phosphorus benefits of white lupin, field pea and faba bean to wheat production in Western Australian soils." University of Western Australia. School of Plant Biology, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0094.
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[Truncated abstract] Soils of Western Australian cropping regions are very low in phosphorous. White lupin, chickpea, and faba bean are being increasingly used in rotations with wheat on these soils. Yield of wheat after a legume crop is frequently higher than its yield after wheat. It has been reported that in addition to nitrogen, legumes can also contribute to improve the availability of phosphorous for the subsequent crops. This PhD research project aimed at optimising the economic returns of wheat-legume rotations through more efficient use of P fertiliser in the legume phase as well as enhanced availability of soil P in the subsequent wheat phase
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Perkins, Sarah Elizabeth Biological Earth & Environmental Sciences Faculty of Science UNSW. "Evaluation and 21st century projections of global climate models at a regional scale over Australia." Awarded By:University of New South Wales. Biological, Earth & Environmental Sciences, 2010. http://handle.unsw.edu.au/1959.4/44906.
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This thesis explores the ability of global climate models (GCMs) to simulate observed conditions at regional scales by examining probability density functions (PDFs) of daily minimum temperature (Tmin), maximum temperature (Tmax) and precipitation (P). Two new measures of model skill are proposed using PDFs of observed and modelled data. The first metric (Sscore) compares the amount of overlap between the two PDFs. The second metric (Tailskill) is the weighted difference between the PDF tails, where extreme events are represented. The resulting measures of skill are used to differentiate, at a regional scale, between weaker and stronger models. It is investigated whether the weaker models bias future projections given by multi-model ensembles, increasing the uncertainty in the range of projected values and the change from the 20th Century. The Sscore is demonstrated to be robust against inhomogenities found in highdensity Australian datasets, and is a simple and quantitative measure of how well each GCM can simulate all observed events. This methodology is executed for twelve Australian regions of varying climates for all Intergovernmental Panel on Climate Change 4th Assessment Report models for which daily data was available for 1961-2000. Across Tmin, Tmax and P some GCMs perform well, demonstrating that some GCMs provide credible simulations of climate at sub-continental scales. Projections of the annual and seasonal mean and yearly return values over the A2 and B1 emission scenarios are investigated. Models are omitted from an ensemble based on their ability to simulate the observed PDF at regional scales. The stronger models are generally in agreement with the change in mean values, particularly for Tmin and Tmax, though it is shown that they vary in their projections of the yearly return value at least twice as much as projections in the mean values. Lastly, a means-based evaluation method, the Sscore and the Tailskill are employed to differentiate between weaker and stronger models for projections in the 20-year return value of Tmin and Tmax. Weaker-skilled ensembles project larger increases in 20-year return values than stronger-skilled ensembles, such that in some regions for maximum temperature the ensembles are statistically significantly different. Demonstrably weaker models bias projections given by an all-model ensemble and should be excluded so the most reliable estimates of future climate can be obtained.
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Cunningham, Shaun Cameron 1971. "Comparative ecophysiology of temperate and tropical rainforest canopy trees of Australia in relation to climate variables." Monash University, Dept. of Biological Sciences, 2001. http://arrow.monash.edu.au/hdl/1959.1/9040.
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Kennedy, Jane. "Factors affecting the retention of dissolved organic carbon in upland soils." Thesis, University of Aberdeen, 1997. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU100041.
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The aim of this thesis was to investigate soil and environmental factors which influence the adsorption of DOC in upland, moorland soils. In Chapter 1 climate change, the greenhouse effect and the global carbon cycle are discussed briefly. A more detailed discussion of carbon cycling in the plant-soil-water system focuses on DOC retention in podzols and the review concludes with a summary of the aims of this thesis. A peaty podzol has greater potential to retain DOC than the other major soil types within the Glen Dye catchment, N.E. Scotland. Retention of DOC by physico-chemical surface interactions occurred in the mineral horizons of the soil where locally high concentrations of amorphous Fe and Al were present. Laboratory experiments using potassium hydrogen phthalate as a source of DOC showed that DOC retention is favoured by longer contact times between soil and solution. Net retention of DOC in the podzol profile is decreased by increasing the solution pH and by repeated wetting/drying and freezing/thawing cycles. As temperature and reaction time increased, respiration becomes more important as a mechanism for depleting solution phthalate DOC concentrations. Annual fluxes of DOC in precipitation, podzolic O, E and Bs soil horizon solution and stream water were estimated for the Burn of Waterhead catchment to be 35, 121, 83, 37 and 48 kg C ha-1yr-1 respectively. The DOC fluxes and the concentrations of related elements varied seasonally, with the largest DOC fluxes produced in the autumn and lowest in the summer. The annual DOC flux from the Burn of Waterhead was lower than fluxes from other catchments at Glen Dye. Results from the field site supported laboratory experimental results which suggested that climate change will result in an increase in the DOC flux from results which suggested that climate change will result in an increase in the DOC flux from peaty podzolic soil.
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Ferraro, Lidia. "Measuring safety climate : the implications for safety performance /." Connect to thesis, 2002. http://repository.unimelb.edu.au/10187/965.
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Safety culture and safety climate are terms that are used often in the context of safety management but are not very well defined or differentiated. This research concentrates on safety climate, a summary concept of employee perceptions of safety management practices within their organisation. There is a common assumption that a positive safety climate results in better safety performance outcomes, yet there is little research evidence to support this notion.Despite being defined as a summary concept, much of the research on safety climate has been empirically driven and has concentrated on identifying the number and content of the dimensions/factors that contribute to the safety climate. Due to a lack of theoretical input in the field, the use of proprietary instruments which are unavailable in the public domain and varied developmental histories of these tools, the findings of past research has been mixed.
This research addresses several of the limitations in the literature on safety climate by using the National Safety Council of Australia’s Safety Climate Survey. The research centres around two main issues; the dimensionality and factor structure of safety climate; and investigation of the applicability of a framework linking safety climate to safety performance.
The project was divided into two studies. Study I is based on archival data collected by the National Safety Council of Australia (NSCA) (N=215, N=127, N=90). Study II utilises data collected specifically for the purposes pf this research (N=226). The survey instrument was further developed for Study II to include scales that allow for a more complete investigation of a framework linking safety climate to safety performance.
A comprehensive validation of the NSCA safety climate survey was conducted. Structural Equation Modelling was utilised to examine various models of the factor structure of safety climate. It was found that safety climate is best understood as a second order concept comprised of several specific first order factors. The factor structure remained consistent across several samples however the strength of the individual factors varied in each sample.
Structural Equation Modelling was also used to investigate the framework of the relationship between safety climate and safety performance. Evidence in support of his model was obtained however some variations to the model were necessary to achieve this support. Reinforcement for the influence of general organisational climate in providing a context for safety climate was revealed. Given that it was not possible to include all aspects of the framework within the statistical model these findings provide a good impetus for further research in this field.
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Hope, Pandora. "The weather and climate of Australia at the Last Glacial Maximum." Connect to thesis, 2005. http://repository.unimelb.edu.au/10187/2884.
Full textAbstract:
The global climate has experienced four glacial cycles in the last 420,000 years, with each cycle characterised by a prolonged period of cooling culminating in maximal glaciation followed by a brief warm period. The most recent period of maximal glaciation is termed the Last Glacial Maximum (LGM) and occurred about 21,000 years ago. We currently live in one of the warm periods. The global climate is changing, and it is becoming more important to understand the extremes of the climate system and how well our modelling capability can capture those extremes.There has been a modelling intercomparison project established to examine how global general circulation models compare in simulating past climates, including the LGM. Analysis and comparison of these model results has been presented for many parts of the globe, but there has not been a comparison of the different model results over the Australian region. This thesis aims to fill that gap and explore the simulated LGM weather and climate of Australia and its drivers in more detail. Comparison with proxy evidence is also undertaken, and inconsistencies seen in the literature addressed.
The Australian climate at the LGM was believed to be generally cooler, drier and possibly windier from proxy evidence in the literature. In the comparison done here the mean temperature and precipitation fields from most models show cooler and drier conditions, with some seasonal variability, but there are some strong outliers. It was found that the differences were not dependent on model resolution, but that the surface parameterisations were highly important for these fields.
The shifts in the circulation were examined both in the model results and with a study of the non-linear link between the wind, surface moisture and dunes, which are a proxy for past winds. All the models simulate a southward shift in the westerlies in the Australian region. This is strongly driven byte prescribed sea-surface temperatures. Australia's current wind regime is conducive to dune building. However, the binding effect of soil moisture (or vegetation) is strong enough to limit present day movement, whereas in the drier climate at the LGM there was a capacity for sand movement. The analysis of dune orientations did not produce conclusive evidence for how the westerlies might have shifted at the LGM.
An apparent enigma in the proxy evidence at the LGM is the high lake levels in Australia’s south east, while most inland lakes were dry. Previous authors believed that the precipitation was still low, but the high lake levels were driven by lowered potential evaporation. The hydrological cycle was generally depressed in the LGM simulations, but the potential for evaporation remained high. Thus an alternative hypothesis is posed based on increased run off due to a known shift in the vegetation types and a lag in the timing of the run off due to snowmelt.
The analysis here shows that our capacity to simulate climates quite different from the present is still developing, but that model results can help explain apparent inconsistencies in the reconstruction of past climates from proxies.
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Chen, Juan. "Mobility and environmental fate of norflurazon and haloxyfop-R methyl ester in six viticultural soils of South Australia /." Title page, contents and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09AEVM/09aevmc518.pdf.
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Chalwell, Shane Thomas Samuel. "Plant communities of greenstone hills of the Eastern Goldfields of Western Australia as analogues for the rehabilitation of rocky waste dumps." Thesis, Chalwell, Shane Thomas Samuel (2003) Plant communities of greenstone hills of the Eastern Goldfields of Western Australia as analogues for the rehabilitation of rocky waste dumps. PhD thesis, Murdoch University, 2003. https://researchrepository.murdoch.edu.au/id/eprint/510/.
Full textAbstract:
The vegetation of greenstone hills in the Kalgoorlie area of the Eastern Goldfields region of Western Australia was studied to identify the key environmental influences on community and species distribution. This information was needed to determine if plant communities of the hills could provide analogues for the rehabilitation of waste rock dumps that are produced as a consequence of open cut mining.
The ridges, slopes and flats adjacent to the main slope were examined and the floristic data sorted into communities. Two structurally and floristically distinct alliances were identified, one dominated by eucalypt species and the other by Acacia quadrimarginea. The eucalypt woodland displayed a taller upper stratum and few groundlayer species and was the dominant vegetation of the flats at the base of the hills. The acacia community was a low woodland and is the dominant vegetation of the hill slopes. Both communities were dominant at an equal number of sites on the ridges of the hills.
An investigation of the environmental variables found that edaphic, rather than topographic, factors were responsible for the community distribution on the hills. The eucalypt woodland showed a strong affinity to soils derived from calcrete, which had higher levels of electrical conductivity and lower exchangeable sodium percentages than the soils of the acacia low woodland. Under such conditions, the clay fraction of the soil remains in a more flocculated state allowing higher rates of water infiltration and hydraulic conductivity compared to the acacia soils. Soil nutrients were found to have a secondary influence on community distribution and had a greater effect on species distribution within alliances.
A study of the seasonal variation in water content of the soils showed that more moisture is retained in the upper soil horizons in the acacia community than in the eucalypt community during the wetter part of the year, indicating the acacia soils had poorer infiltration properties than the eucalypt soils. The distribution of drought tolerant species such as A. quadrimarginea and Prostanthera incurvata was found to be correlated to soil moisture content of the dry season whilst no correlation was found for the eucalypts at any time of the year.
Seasonal comparisons of leaf moisture content and xylem pressure potential showed that the eucalypts maintained their total leaf moisture content throughout the year whereas species such as A. quadrimarginea and Allocasuarina campestris recorded high levels of desiccation of their leaf tissue over the summer. The eucalypts also maintained a more consistent pre-dawn xylem pressure potential throughout the year than either A. quadrimarginea or the shrub species Dodonaea microzyga, indicating a greater degree of stomatal control and access to a more consistent soil water supply. The eucalypts require access to a greater soil volume than the acacias or shrubs in order to ensure sufficient water supplies for the maintenance of tissue moisture levels throughout the year. In this way, the eucalypts are able to effectively avoid the summer drought, whereas the acacias and shrubs are able to tolerate desiccation of their leaf tissues over this period.
Investigations of the germination requirements and early seedling survival of prominent species from the greenstone hills indicated that fire may be a factor in the regeneration of most hills species. All studied species were either tolerant of or responded positively to the application of dry heat. In relation to seedling establishment on waste dumps, increasing the soil moisture content of waste dump soils increased the germination rate of most species but did not result in greater seedling survival at the end of the first summer. The provision of microsites which encouraged root development and provided protection for the young seedlings was found to be more important in reducing mortality rates in the first year than increasing the total germination.
The study emphasized the importance of physical soil factors and the soil moisture regime in the distribution of eucalypt and acacia communities on the greenstone hills. A species' response to drought stress strongly influences its ability to compete for soil water on different soil types. The eucalypts studied in this project dominated on soils where there is better recharge of subsoil water reserves which can be accessed over the summer period to maintain tissue water levels. Acacias are tolerant of tissue desiccation and will compete successfully on shallower soils and where hydraulic conductivity is poor.
Although the project was valuable in identifying water relations as the main control on community distribution on the hills, waste dumps are not strictly analogues of intact greenstone hills due to the differences in rock type and profile formation. Electrical conductivity levels are also higher due to extraction processes. However, the environmental relationships of the different species show that the more drought tolerant species such as Allocasuarina campestris, Acacia quadrimarginea and understorey species associated with them, may be suitable species to form the basis of vegetation reinstatement on waste dumps in the Kalgoorlie region.
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Chalwell, Shane Thomas Samuel. "Plant communities of greenstone hills of the Eastern Goldfields of Western Australia as analogues for the rehabilitation of rocky waste dumps." Chalwell, Shane Thomas Samuel (2003) Plant communities of greenstone hills of the Eastern Goldfields of Western Australia as analogues for the rehabilitation of rocky waste dumps. PhD thesis, Murdoch University, 2003. http://researchrepository.murdoch.edu.au/510/.
Full textAbstract:
The vegetation of greenstone hills in the Kalgoorlie area of the Eastern Goldfields region of Western Australia was studied to identify the key environmental influences on community and species distribution. This information was needed to determine if plant communities of the hills could provide analogues for the rehabilitation of waste rock dumps that are produced as a consequence of open cut mining.
The ridges, slopes and flats adjacent to the main slope were examined and the floristic data sorted into communities. Two structurally and floristically distinct alliances were identified, one dominated by eucalypt species and the other by Acacia quadrimarginea. The eucalypt woodland displayed a taller upper stratum and few groundlayer species and was the dominant vegetation of the flats at the base of the hills. The acacia community was a low woodland and is the dominant vegetation of the hill slopes. Both communities were dominant at an equal number of sites on the ridges of the hills.
An investigation of the environmental variables found that edaphic, rather than topographic, factors were responsible for the community distribution on the hills. The eucalypt woodland showed a strong affinity to soils derived from calcrete, which had higher levels of electrical conductivity and lower exchangeable sodium percentages than the soils of the acacia low woodland. Under such conditions, the clay fraction of the soil remains in a more flocculated state allowing higher rates of water infiltration and hydraulic conductivity compared to the acacia soils. Soil nutrients were found to have a secondary influence on community distribution and had a greater effect on species distribution within alliances.
A study of the seasonal variation in water content of the soils showed that more moisture is retained in the upper soil horizons in the acacia community than in the eucalypt community during the wetter part of the year, indicating the acacia soils had poorer infiltration properties than the eucalypt soils. The distribution of drought tolerant species such as A. quadrimarginea and Prostanthera incurvata was found to be correlated to soil moisture content of the dry season whilst no correlation was found for the eucalypts at any time of the year.
Seasonal comparisons of leaf moisture content and xylem pressure potential showed that the eucalypts maintained their total leaf moisture content throughout the year whereas species such as A. quadrimarginea and Allocasuarina campestris recorded high levels of desiccation of their leaf tissue over the summer. The eucalypts also maintained a more consistent pre-dawn xylem pressure potential throughout the year than either A. quadrimarginea or the shrub species Dodonaea microzyga, indicating a greater degree of stomatal control and access to a more consistent soil water supply. The eucalypts require access to a greater soil volume than the acacias or shrubs in order to ensure sufficient water supplies for the maintenance of tissue moisture levels throughout the year. In this way, the eucalypts are able to effectively avoid the summer drought, whereas the acacias and shrubs are able to tolerate desiccation of their leaf tissues over this period.
Investigations of the germination requirements and early seedling survival of prominent species from the greenstone hills indicated that fire may be a factor in the regeneration of most hills species. All studied species were either tolerant of or responded positively to the application of dry heat. In relation to seedling establishment on waste dumps, increasing the soil moisture content of waste dump soils increased the germination rate of most species but did not result in greater seedling survival at the end of the first summer. The provision of microsites which encouraged root development and provided protection for the young seedlings was found to be more important in reducing mortality rates in the first year than increasing the total germination.
The study emphasized the importance of physical soil factors and the soil moisture regime in the distribution of eucalypt and acacia communities on the greenstone hills. A species' response to drought stress strongly influences its ability to compete for soil water on different soil types. The eucalypts studied in this project dominated on soils where there is better recharge of subsoil water reserves which can be accessed over the summer period to maintain tissue water levels. Acacias are tolerant of tissue desiccation and will compete successfully on shallower soils and where hydraulic conductivity is poor.
Although the project was valuable in identifying water relations as the main control on community distribution on the hills, waste dumps are not strictly analogues of intact greenstone hills due to the differences in rock type and profile formation. Electrical conductivity levels are also higher due to extraction processes. However, the environmental relationships of the different species show that the more drought tolerant species such as Allocasuarina campestris, Acacia quadrimarginea and understorey species associated with them, may be suitable species to form the basis of vegetation reinstatement on waste dumps in the Kalgoorlie region.
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Gottschalk, Pia. "Modelling soil organic carbon dynamics under land use and climate change." Thesis, University of Aberdeen, 2012. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=186643.
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Soil organic matter (SOM) models simplify the complex turnover dynamics of organic matter in soils. Stabilization mechanisms are currently thought to play a dominant role in SOM turnover but they are not explicitly accounted for in most SOM models. One study addresses the implementation of an approach to account for the stabilization mechanism of physical protection in the SOC model RothC using 13C abundance measurements in conjunction with soil size fractionation data. SOM models are increasingly used to support policy decisions on carbon (C) mitigation and credibility of model predictions move into the focus of research. A site scale, Monte Carlo based model uncertainty analysis of a SOM model was carried out. One of the major results was that uncertainty and factor importance depend on the combination of external drivers. A different approach was used with the SOM ECOSSE model to estimate uncertainties in soil organic carbon (SOC) stock changes of mineral and organic soils in Scotland. The average statistical model error from site scale evaluation was transferred to regional scale uncertainty to give an indication of the uncertainty in national scale predictions. National scale simulations were carried out subsequently to quantify SOC stock changes differentiating between organic and mineral soils and land use change types. Organic soils turned out to be most vulnerable to SOC losses in the last decades. The final study of this thesis emplyed the RothC model to simulate possible futures of global SOC stock changes under land use change and ten different climate scenarios. Land use change turned out to be of minor importance. The regionally balance between soil C inputs and decomposition leads to a diverse map of regional C gains and losses with different degrees of certainty.
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Hill, Robert S. "Evolution of the Australian flora in response to Cenozoic climate change /." Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09S.D/09s.dh6469.pdf.
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Case, Sean Daniel Charles. "Biochar amendment and greenhouse gas emissions from agricultural soils." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/8049.
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The aim of this study was to investigate the effects of biochar amendment on soil greenhouse gas (GHG) emissions and to elucidate the mechanisms behind these effects. I investigated the suppression of soil carbon dioxide (CO2) and nitrous oxide (N2O) emissions in a bioenergy and arable crop soil, at a range of temperatures and with or without wetting/drying cycles. More detailed investigation on the underlying mechanisms focused on soil N2O emissions. I tested how biochar altered soil physico-chemical properties and the subsequent effects on soil N2O emissions. In addition, 15N pool dilution techniques were used to investigate the effect of biochar on soil N transformations. Biochar amendment significantly suppressed soil GHG emissions for two years within a bioenergy soil in the field and for several months in an arable soil. I hypothesised that soil CO2 emissions were suppressed under field conditions by a combination of mechanisms: biochar induced immobilisation of soil inorganic-N (BII), increased C-use efficiency, reduced C-mineralising enzyme activity and adsorption of CO2 to the biochar surface. Soil CO2 emissions were increased for two days following wetting soil due to the remobilisation of biochar-derived labile C within the soil. Soil N2O emissions were suppressed in laboratory incubations within several months of biochar addition due to increased soil aeration, BII or increased soil pH that reduced the soil N2O: N2 ratio; effects that varied depending on soil inorganic-N concentration and moisture content. These results are significant as they consistently demonstrate that fresh hardwood biochar has the potential to reduce soil GHG emissions over a period of up to two years in bioenergy crop soil, while simultaneously sequestering C within the soil. They also contribute greatly to understanding of the mechanisms underlying the effect of biochar addition on soil N transformations and N2O emissions within bioenergy and arable soils. This study supports the hypothesis that if scaled up, biochar amendment to soil may contribute to significant reductions in global GHG emissions, contributing to climate change mitigation. Further studies are needed to ensure that these conclusions can be extrapolated over the longer term to other field sites, using other types of biochar.
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Nathan, Muhammad. "Clay movement in a saline-sodic soil toposequence." Title page, contents and summary only, 2001. http://web4.library.adelaide.edu.au/theses/09A/09an274.pdf.
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Includes bibliographical references (leaves 78-86) In the Herrmanns sub-catchment in the Mt. Lofty Ranges (near Mt. Torrens) soil sodicity was the dominant factor in causing clay to disperse in the eroded area along the foot slopes, wheras in non-eroded areas of the mid-slopes and on the stream banks, the dispersive power of sodicity was attenuated by the flocculative power of other soil properties.
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Bhatti, Muhammad Ali. "Genetic variation in naturalized wild radish (Raphanus raphanistrum L.) populations in the mediterranean climate of south-western Australia." University of Western Australia. School of Plant Biology, 2004. http://theses.library.uwa.edu.au/adt-WU2005.0012.
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[Truncated abstract] Wild radish (Raphanus raphanistrum L.), an outcrossing annual plant, is one of the most widespread and successful colonising weeds in the Australian wheat belt. It was introduced accidentally during the latter part of the 19th century, apparently independently through the major ports of southern Australia. The widespread success of wild radish, and therefore the likelihood of distinct populations, gives us the opportunity to study the colonizing process with adaptation in annual outbreeding species, and to explore their genetic diversity. The aims of this thesis were to study the genetic diversity of wild radish and to investigate which factors are important in its success. After an initial review of the literature (chapter 2), the thesis describes experiments where genetic variation between and within populations was compared at 55 sites in transects across the wheat belt and high rainfall zones of temperate Western Australia (chapter 3). In chapter 4, variation in life history traits was compared with variation in AFLP molecular markers. The role of seed dormancy in the survival of the species was examined in chapter 5, and variation in the oil content of seeds and their fatty acid composition was examined in chapter 6. Finally, the results were discussed in chapter 7 with special reference to the adaptive value of outcrossing in annual weeds. The results suggest that wild radish has evolved to fit the Australian environment. However, measurement of 14 morphological and phenological characters showed that in most cases within site variation was much greater than that between sites. Most of the variation between sites was associated with geoclusters, a name given to zones of similar environmental conditions in regard to rainfall and temperature. Thus plants from areas with high rainfall and low temperature produced longer, wider pods with more segments, heavier seeds and flowered later than plants from more arid areas.
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Heinze, Heather W. "Anthropogenic Influences and Meteorological Effects: How They are Changing the Sand Beaches in Southern Maine." Fogler Library, University of Maine, 2001. http://www.library.umaine.edu/theses/pdf/HeinzeHW2001.pdf.
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Vagh, Yunous. "Mining climate data for shire level wheat yield predictions in Western Australia." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2013. https://ro.ecu.edu.au/theses/695.
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Climate change and the reduction of available agricultural land are two of the most important factors that affect global food production especially in terms of wheat stores. An ever increasing world population places a huge demand on these resources. Consequently, there is a dire need to optimise food production.
Estimations of crop yield for the South West agricultural region of Western Australia have usually been based on statistical analyses by the Department of Agriculture and Food in Western Australia. Their estimations involve a system of crop planting recommendations and yield prediction tools based on crop variety trials. However, many crop failures arise from adherence to these crop recommendations by farmers that were contrary to the reported estimations. Consequently, the Department has sought to investigate new avenues for analyses that improve their estimations and recommendations.
This thesis explores a new approach in the way analyses are carried out. This is done through the introduction of new methods of analyses such as data mining and online analytical processing in the strategy. Additionally, this research attempts to provide a better understanding of the effects of both gradual variation parameters such as soil type, and continuous variation parameters such as rainfall and temperature, on the wheat yields.
The ultimate aim of the research is to enhance the prediction efficiency of wheat yields. The task was formidable due to the complex and dichotomous mixture of gradual and continuous variability data that required successive information transformations. It necessitated the progressive moulding of the data into useful information, practical knowledge and effective industry practices. Ultimately, this new direction is to improve the crop predictions and to thereby reduce crop failures.
The research journey involved data exploration, grappling with the complexity of Geographic Information System (GIS), discovering and learning data compatible software tools, and forging an effective processing method through an iterative cycle of action research experimentation. A series of trials was conducted to determine the combined effects of rainfall and temperature variations on wheat crop yields. These experiments specifically related to the South Western Agricultural region of Western Australia. The study focused on wheat producing shires within the study area. The investigations involved a combination of macro and micro analyses techniques for visual data mining and data mining classification techniques, respectively.
The research activities revealed that wheat yield was most dependent upon rainfall and temperature. In addition, it showed that rainfall cyclically affected the temperature and soil type due to the moisture retention of crop growing locations. Results from the regression analyses, showed that the statistical prediction of wheat yields from historical data, may be enhanced by data mining techniques including classification.
The main contribution to knowledge as a consequence of this research was the provision of an alternate and supplementary method of wheat crop prediction within the study area. Another contribution was the division of the study area into a GIS surface grid of 100 hectare cells upon which the interpolated data was projected. Furthermore, the proposed framework within this thesis offers other researchers, with similarly structured complex data, the benefits of a general processing pathway to enable them to navigate their own investigations through variegated analytical exploration spaces. In addition, it offers insights and suggestions for future directions in other contextual research explorations.
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Handayanto, Eko. "Texture contrast in some soils from Southern Australia in relation to their parent materials." Adelaide, 1988. http://web4.library.adelaide.edu.au/theses/09A/09ah236.pdf.
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Ferris, David Glen. "Evolutionary differentation in Lolium L. (Ryegrass) in response to the Mediterranean-type climate and changing farming systems of Western Australia." University of Western Australia. School of Plant Biologyd%695 Electronic theses, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0040.
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Adaptation of exotic species to the Australian landscape poses a serious threat to the integrity of natural ecosystems and profitability of current farming systems. Ryegrass, an outcrossing species complex (Lolium spp.) and an intractable weed of cropping systems, was used as a candidate to further investigate adaptation within Mediterranean-type environments. Evolutionary differentiation in naturalised populations and their adaptive potential were examined in common gardens by characterising the genetic variability within and between 80 populations collected across 8 cropping regions, and 30 populations from adjacent paddocks differing in key management inputs. Morphological variability within and between populations was not found to be simply the consequence of variable distribution in the number and frequency of taxonomic species which colonised Australia with European settlement. Most plants were intermediate in appearance between L. rigidum Gaud. and L. multiflorum Lam. Ecotypic differentiation between regions was clearly evident even though the vast majority of variation in life history traits was found within sites (except for flowering time, 18%). Overall, as growing season length decreased flowering time and spikelet number per spike also decreased; conversely, florets per spikelet, flag leaf size, and population uniformity increased. Larger leaves and lower maternal investment per seed may confer an adaptive advantage in more arid, cropping intensive habitats where competition to intercept light is intense and moisture availability during seed fill more uncertain. By contrast smaller, more numerous leaves and a wider diversity in life history traits may confer an adaptive advantage in higher rainfall, grazing intensive habitats where the risk of predation (consumption) of plant parts is greater and a wider range of biotic pressures abound. iv However, in spite of the large amount of variability in morphological traits upon which selection could act, no evidence was found to support the claim that ryegrass would change in response to mechanical seed collection at harvest (chaff-cart use) to circumvent such control. The frequency of a deleterious adaptation to acetyl-coenzyme A carboxylase inhibiting herbicides appeared stable in one population after 13 years without herbicide use. Notwithstanding, the frequency of herbicide resistance declined sharply within a 20 m zone adjacent to a susceptible area but this has only limited agronomic benefit. By contrast, the potential to decimate the frequency of resistance by sowing herbicide-susceptible tetraploid ryegrass was identified, and glasshouse results were consistent with the minority cytotype exclusion principle. Possible experimental approaches to field validate this novel concept and key issues to be resolved are discussed.
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Wei, Jiangfeng. "Land-atmosphere interaction and climate variability." Diss., Available online, Georgia Institute of Technology, 2007, 2007. http://etd.gatech.edu/theses/available/etd-05162007-151312/.
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Thesis (Ph. D.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2008.Stieglitz, Marc, Committee Member ; Guillas, Serge, Committee Member ; Fu, Rong, Committee Member ; Curry, Judith, Committee Member ; Dickinson, Robert, Committee Chair.
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Bernal, Blanca. "Carbon Pools And Profiles In Wetland Soils: The Effect Of Climate And Wetland Type." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1218226611.
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Wiesner, Sarah [Verfasser], and Annette [Akademischer Betreuer] Eschenbach. "Observing the impact of soils on local urban climate / Sarah Wiesner. Betreuer: Annette Eschenbach." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2013. http://d-nb.info/1036729303/34.
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Kalinski, Kira [Verfasser]. "Ecosystem services of urban floodplain soils under changing climate and water management / Kira Kalinski." Hamburg : Staats- und Universitätsbibliothek Hamburg Carl von Ossietzky, 2021. http://d-nb.info/123705043X/34.
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Deiglmayr, Kathrin. "Community structure and activity of nitrate-reducing microorganisms in soils under global climate change." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:100-opus-1515.
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Yusran, Fadly Hairannoor. "Soil organic matter decomposition : effects of organic matter addition on phosphorus dynamics in lateritic soils." University of Western Australia. School of Earth and Geographical Sciences, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0120.
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[Truncated abstract] Relationships between the persistence of organic matter added to soil, the dynamics of soil organic carbon (C) and phosphorus (P) were examined in four experiments on lateritic soils of Western Australia. The main objective was to quantify the release of P following organic matter application in soils which have high P adsorbing capacity. Another objective was to confirm that due to its recalcitrant materials, the effect of peat lasted longer in soil than other sources of organic matter in terms of increasing plant-available P fractions. Three experiments were conducted under glasshouse conditions for various lengths of time, with nine- to twelve-month incubations to investigate these hypotheses. As expected, organic matter with lower C:N ratios than peat (lucerne hay) decomposed more rapidly compared with peat, and the most active mineralisation took place within the first three months of incubation. Soil organic-C (extracted by 0.5 M K2SO4) had a significant positive correlation with P extracted with 0.5 M NaHCO pH 8.53. For a higher application rate (120 ton ha-1), peat was better than wheat straw and lucerne hay in increasing extractable bicarbonate-P concentrations in soil, especially at incubation times up to 12 months. Throughout the experiment, peat was associated with a steady increase in all parameters measured. In contrast to peat, nutrient release from lucerne hay and wheat straw was rapid and diminished over time. There was a tendency for organic-C (either in the form of total extractable organic-C or microbial biomass-C) to steadily increase in soil with added peat throughout the experiment. Unlike wheat straw and lucerne hay, extractable organic-C from peat remained in soil and there was less C loss in the form of respiration. Therefore, peat persisted and sequestered C to the soil system for a longer time than the other source of organic matter. Freshly added organic matter was expected to have a greater influence on P transformation from adsorbed forms in lateritic soils than existing soil organic matter. By removing the existing soil organic matter, the effect of freshly applied organic matter can be determine separately from that of the existing soil organic matter for a similar organic-C content. In order to do this, some soil samples were combusted up to 450° C to eliminate inherent soil organic matter. The release of P was greater when organic-C from fresh organic matter was applied to combusted soils than in uncombusted soils that contained the existing soil organic matter. The exception only applied for parameters related to soil micro-organisms such as biomass-C and phosphatase. For such parameters, new soil organic matter did not create conditions favourable for organisms to increase in activity despite the abundance of organic matter available. More non-extractable-P was formed in combusted soils compared to bicarbonate-P and it contributed to more than 50% of total-P. As for the first experiment, peat also showed a constant effect in increasing bicarbonate extractable-P in the soil
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Anderson, Ian C., of Western Sydney Nepean University, of Science Engineering and Technology Faculty, and School of Science. "Inter- and intraspecific variation in Pisolithus from central and eastern mainland Australia." THESIS_FST_SS_Anderson_I.xml, 2000. http://handle.uws.edu.au:8081/1959.7/237.
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Pisolithus is an important ectomycorrhizal genus world-wide, however to date we remain largely ignorant of the genetic and functional variation that exists within isolates of this genus. Fifty-three isolates of Pisolithus were obtained from various locations in central and eastern Australia and genetic variation within the isolates was assessed using ITS-RFLP and ITS sequencing analyses. RFLP analysis initially grouped the isolates into eight RFLP types. Neighbour-joining analysis of ITS sequences with Pisolithus ITS sequences available in databases clustered the majority of isolates into four groups within two major clades, each comprising isolates of similar basidiospre characteristics. Most Australian isolates correspond with recent provisional descriptions of P. albus or P. marmoratus. One isolate (LJ30) had low sequence identity (61.6-78.0%) to the other isolates and probably represents a separate undescribed Australian species. Significant intraspecific variation was observed in ITS-RFLP profiles for the putative P. albus isolates, suggesting that the sole use of RFLP analysis in diversity assessment may over-estimate Pisolithus species richness. Investigations were also initiated to identify if a relationship exists between genetic and physiological diversity in Australian Pisolithus. It is, however, clear that extensive physiological variation exists in Australian Pisolithus isolates. The size and distribution of genets of Australian Pisolithus species I and II ( putative P. albus and P. marmoratus) was also assessed using microsatellite-primed PCR to gain a better understanding of the likely distribution of underground mycelial networks and possible reproduction strategies in native soils. The data demonstrate that both species have the ability to be long-lived and extend for significant distances in native soils in undisturbed conditions. The field site for Pisolithus species I, however, also contained of a large number of small individuals suggesting that this species may employ a life-history strategy combining r-, C and S characteristics depending on local soil conditionsDoctor of Philosophy (PhD)
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Söderström, Ellen. "Men, masculinities and climate change : A study of climate change impacts in cases from Greenland, Australia Peru and South Africa." Thesis, Linnéuniversitetet, Institutionen för samhällsstudier (SS), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-44709.
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‘Climate change is not gender neutral’ is a statement that has gained more recognition within the climate change debate over the last decade. This has resulted in a new field of research called gender and climate change. The mainstream gender and climate change debate has earlier almost exclusively focused on women’s vulnerability. A brief reading of the literature clearly shows that men are rarely observed in this context. The objective of this thesis is to broaden the understanding of the relation between gender and climate change by bringing men into the discussion. I have selected four cases/countries where existing research on men’s gendered experiences of climate change are mentioned. These take place in Greenland, Australia, Peru and South Africa. The result show five common findings between the cases: gendered responsibilities, changing traditional gender roles, psychological impacts, alcohol consumption and violence against women. The concept hegemonic masculinities is utilized as a framework used to understand why men are negatively affected by climate change. Masculine norms of attitudes and behavior identified in the multiple case studies are invulnerability and unwillingness to seek help. The analysis show that in times of climate variability can masculine norms be damaging for both men and women. A second analytical framework, the gender transformative approach brings the analysis to critically reflect upon masculinities and climate change as functions of power. From this perspective this thesis concludes that the gender and climate change discourse needs to move beyond a focus on women’s vulnerabilities, which divide the world into two classes: women as victims and men as perpetrators. This approach rather urge for a focus on the structures of power and domination within laws, behaviors and institutions that generates injustices.
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Lotfollahi, Mohammad. "The effect of subsoil mineral nitrogen on grain protein concentration of wheat." Title page, table of contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phl882.pdf.
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Copy of author's previously published work inserted. Bibliography: leaves 147-189. This project examines the uptake of mineral N from the subsoil after anthesis and its effect on grain protein concentration (GPC) of wheat. The overall objective is to examine the importance of subsoil mineral N and to investigate the ability of wheat to take up N from the subsoil late in the season under different conditions of N supply and soil water availability. Greenhouse experiments investigate the importance of subsoil mineral N availability on GPC of wheat and the factors that contribute to the effective utilisation of N. The recovery of N from subsoil, the effect of split N application on GPC and short term N uptake by the wheat at different rooting densities are also studied.
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Odeh, Inakwu Ominyi Akots. "Soil pattern recognition in a South Australian subcatchment /." Title page, contents and abstract only, 1990. http://web4.library.adelaide.edu.au/theses/09PH/09pho23.pdf.
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Howard, S. "Variation in chain-length of leaf wax N-Alkanes in plants and soils across Australia." Thesis, 2014. http://hdl.handle.net/2440/110468.
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This item is only available electronically.Long chain n-alkanes are produced as part of leaf epicuticular wax and are ideal biomarkers for palaeoclimatology and palaeoecology due to their persistence in soils and sediments. Sedimentary records often show shifts in average chain-lengths (ACL) of n-alkanes, both across geologic time and modern-day climate gradients and this shift may be climate driven. Australia spans a broad range of different climate conditions providing an ideal study area for investigating the relationship of ACL to climate. The Terrestrial Ecosystem Research Network (TERN) has developed a network of biodiversity monitoring plots (AusPlots and TREND) at which plant and soil samples are collected and made available to the research community. By analysing n-alkane ACL present in plants and soils collected from these sites and comparing with each site's respective climatic conditions, this study examines whether ACL of leaf wax n-alkanes varies systematically in modern plants and soils in relation to climate over a N-S transect of Australia. Specifically, this study examines whether: (1) ACL in plants correlates with different climate variables. (2) ACL measured in soil represents a weighted average of the ACL of the dominant plant species at each site. (3) ACL signature in the soils correlates to different climate variables. This study finds no relationship between the different climate variables to ACL of modern plants. Further, the weighted average of the dominant plant species ACL from each site analysed is a poor predictor of the actual ACL present in the soils. In contrast to ACL from plants, the ACL from the soils shows a strong relationship with temperature and aridity measures. Soils may correlate better with climate because they integrate a long-term average of highly variable ACL values from all contributing organisms. This study supports climate as a driver of ACL in sediments across space and time.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2014
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Donohue, Randall James. "Vegetation - water dynamics in the Australian landscape." Phd thesis, 2009. http://hdl.handle.net/1885/148238.
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Tiver, Fleur. "Vegetation patterns of eastern South Australia : edaphic control and effects of herbivory / by Fleur Tiver." Thesis, 1994. http://hdl.handle.net/2440/21519.
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Ye, Wei. "Climate impacts on streamflow in Australian catchments." Phd thesis, 1996. http://hdl.handle.net/1885/144326.
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"Shallow Horizontal GCHP Effectiveness in Arid Climate Soils." Master's thesis, 2014. http://hdl.handle.net/2286/R.I.27552.
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abstract: Ground coupled heat pumps (GCHPs) have been used successfully in many environments to improve the heating and cooling efficiency of both small and large scale buildings. In arid climate regions, such as the Phoenix, Arizona metropolitan area, where the air condi-tioning load is dominated by cooling in the summer, GCHPs are difficult to install and operate. This is because the nature of soils in arid climate regions, in that they are both dry and hot, renders them particularly ineffective at dissipating heat.
The first part of this thesis addresses applying the SVHeat finite element modeling soft-ware to create a model of a GCHP system. Using real-world data from a prototype solar-water heating system coupled with a ground-source heat exchanger installed in Menlo Park, California, a relatively accurate model was created to represent a novel GCHP panel system installed in a shallow vertical trench. A sensitivity analysis was performed to evaluate the accuracy of the calibrated model.
The second part of the thesis involved adapting the calibrated model to represent an ap-proximation of soil conditions in arid climate regions, using a range of thermal properties for dry soils. The effectiveness of the GCHP in the arid climate region model was then evaluated by comparing the thermal flux from the panel into the subsurface profile to that of the prototype GCHP. It was shown that soils in arid climate regions are particularly inefficient at heat dissipation, but that it is highly dependent on the thermal conductivity inputted into the model. This demonstrates the importance of proper site characterization in arid climate regions. Finally, several soil improvement methods were researched to evaluate their potential for use in improving the effectiveness of shallow horizontal GCHP systems in arid climate regions.Dissertation/Thesis
Masters Thesis Civil Engineering 2014