Academic literature on the topic 'Soil salinization – Western Australia'
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Journal articles on the topic "Soil salinization – Western Australia"
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Hick, PT, and WGR Russell. "Some spectral considerations for remote sensing of soil salinity." Soil Research 28, no. 3 (1990): 417. http://dx.doi.org/10.1071/sr9900417.
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The National Soil Conservation Program (NSCP) and CSIRO funded a research project titled Remote Sensing of Agricultural Salinity, which gathered field and airborne reflectance data for study sites in areas of dryland agricultural salinity in Western Australia. Multivariate techniques are employed to analyse these data gathered over a 3-year period to determine optimum, spectral and temporal considerations for maximizing information content. This report concentrates on some of the spectral aspects and concludes that: spectral bands, existing in currently available remote sensing systems, may not be optimal for the delineation of salinity; that volunteer vegetation indicated the impact of increasing salinity; and that minor amounts of soluble salts in surface soils will modify spectra. The usefulness of portable field spectroradiometers and airborne scanning systems are also assessed for the discrimination of areas of land in the early stages of the effects of salinization.
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Wang, Bo, Xinguang Dong, Zhihui Wang, and Guoqiang Qin. "Characterizing Spatiotemporal Variations of Soil Salinization and Its Relationship with Eco-Hydrological Parameters at the Regional Scale in the Kashi Area of Xinjiang, China from 2000 to 2017." Water 13, no. 8 (April 14, 2021): 1075. http://dx.doi.org/10.3390/w13081075.
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Soil salinization is one of the most serious issues of land degradation, especially in inland drylands, such as the Kashgar region in the Xinjiang province, western China. The investigation of the spatiotemporal variations of soil salinization and its causes is critical for regional ecological restoration and social development. In this study, salinization severity was firstly interpreted in Kashgar region for the years 2000, 2010, and 2017 using multitemporal Landsat images, and the spatiotemporal variations of salinized soil area, salinization severity index, and important index of salinization change were then analyzed using transition matrix method. Finally, the relationship between salinization and eco-hydrological parameters at the regional scale was investigated using correlation analysis and multivariate linear regression. The results show that salinized soil is mainly concentrated in irrigated oasis areas. Although the decrease rate of total salinized soil area is decreasing, the decrease rate of average salinization severity is increasing gradually. There is an increasing trend for the improved area of salinized soil, whereas an opposite trend was observed for the deteriorated area of salinized soil. The conversion from extremely severe salinized soil to the severe ones was the dominant transforming type from 2000 to 2017; meanwhile, the transformation from non-salinized soil to salinized soil for the newly reclaimed farmland was observed, indicating that some necessary irrigation control measures must be taken to avoid further soil salinizing. A significant negative correlation between salinization severity and evapotranspiration, normalized difference vegetation index (NDVI) was observed, implying that soil structure change induced by vegetation, associated with high evapotranspiration (ET) and low land surface temperature (LST), played a positive role in alleviating soil salinization in this region. It is concluded that the soil salinization had been alleviated from 2000 to 2017, mainly due to the combined effects of the farmland expansion and the reasonable irrigation system.
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Löffler, Ernst. "Soil erosion and soil salinization in Australia (Érosion et salinisation du sol en Australie)." Bulletin de l'Association de géographes français 69, no. 2 (1992): 161–67. http://dx.doi.org/10.3406/bagf.1992.1624.
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Ive, J. R., P. A. Walker, and K. D. Cocks. "Spatial modelling of dryland salinization potential in Victoria, Australia." Land Degradation and Development 3, no. 1 (April 1992): 27–36. http://dx.doi.org/10.1002/ldr.3400030104.
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Zsembeli, József, and Lilla Szűcs. "Environmental friendly irrigation of vegetables with high salt content water." Acta Agraria Debreceniensis, no. 61 (September 18, 2014): 115–19. http://dx.doi.org/10.34101/actaagrar/61/2053.
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Horticultural activities have been characteristic in the hobby gardens located in the northern and western areas around the town of Karcag for more than 300 years. During the droughty summer periods, characteristic to the region, the water demand of vegetables and fruit trees are covered by irrigation, for that the water is gained from drilled wells. These well waters contain high amount of dissolved salts contributing to the secondary salinization of the soil. Taking these facts into consideration an irrigation experiment was set at the lysimeter station of Karcag Research Institute. Our goal was to mitigate the risk of secondary salinization generated by irrigation with waters of high salt content and to survey the application possibilities of soil preserving irrigation.
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Dvurechenskya, Elena. "TECHNOGENIC HALOGENESIS IN THE MIDDLE TAIGA OF WESTERN SIBERIA AND EFFECTS OF SOIL SALINIZATION." Acta Geobalcanica 7, no. 3 (October 25, 2020): 101–7. http://dx.doi.org/10.18509/agb.2021.14.
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SINGH, B., and R. J. GILKES. "Properties of soil kaolinites from south-western Australia." Journal of Soil Science 43, no. 4 (December 1992): 645–67. http://dx.doi.org/10.1111/j.1365-2389.1992.tb00165.x.
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Cochrane, HR, G. Scholz, and AME Vanvreswyk. "Sodic soils in Western Australia." Soil Research 32, no. 3 (1994): 359. http://dx.doi.org/10.1071/sr9940359.
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Sodic soils are common throughout Western Australia, particularly in the south-west agricultural area where they occur mainly as duplex or gradational profiles. Soils with sodic properties are dominant in 26% of the state; saline-sodic sediments and soils in intermittent streams, lakes and estuarine plains occupy a further 5%. Sodic soils are moderately common throughout the south and western portion of the rangeland areas (38% of the state). The south-west coastal sands and the desert and rangeland soils to the north and east of the state are rarely sodic. Although sodicity has been recognized as a discrete problem in W.A. soils since the 1920s, the extent and severity of sodicity has been satisfactorily described only for small areas of the state and most land managers are unaware of the role sodicity plays in limiting the productivity of their soils. Sodicity is implicated in a diversity of problems for both agricultural and non-agricultural uses of Western Australian soils. Subsoil impermeability is probably the most widespread of these, but no comprehensive, quantitative assessment of the influence of exchangeable sodium on subsoil properties has been undertaken. Topsoil sodicity is much less extensive but can severely restrict land productivity, particularly on sandy loam and finer textured soils which set hard when dry. The physical behaviour of Western Australian topsoils cannot usefully be predicted from measurements of exchangeable sodium alone because soils differ so greatly in their response to changing exchangeable sodium. Some remain structurally stable at ESP values >15 while others are so 'sodium-sensitive' that they exhibit highly dispersive behaviour at ESP values as low as 2%. Land values over much of the dryland farming and pastoral areas of W.A. do not justify sustained use of amendments which would reduce soil exchangeable sodium contents. Efficient management of sodic soils in these areas must rely on the prevention of degradation and the use of biological and physical means to maintain adequate soil physical properties. Effective restoration of degraded sodic soils, however, often does require application of inorganic amendments in combination with tillage to initiate structural recovery. Sodicity is currently not considered to be a problem at any of the three main irrigation areas in W.A., but all have sodic soil within their potentially irrigable lands, which may limit their future expansion.
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Dvurechenskaya, Elena B. "HALOGENESIS IN OLIGOTROPHIC SOILS OF THE MIDDLE TAIGA OF WESTERN SIBERIA." Географический вестник = Geographical bulletin, no. 3(54) (2020): 148–58. http://dx.doi.org/10.17072/2079-7877-2020-3-148-158.
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The paper provides analysis of salinization processes in the soils of middle taiga due to oil and petroleum products pollution of humid landscapes of Western Siberia. The specific features of man-made chloride-sodium halogenesis which develops in hydromorphic soils of Western Siberia have been investigated. The obtained materials have been initially processed: salt content, alkaline-acid characteristics, soil absorbent complex composition, and organic carbon content have been determined. There have been identified differences in lateral and radial migration of salts in peat bog soils of ryam and ridge-hollow bogs.
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Hart, R. D., T. G. St Pierre, R. J. Gilkes, A. J. McKinley, S. Siradz, and Balwant Singh. "Iron in soil kaolins from Indonesia and Western Australia." Clay Minerals 37, no. 4 (December 2002): 671–85. http://dx.doi.org/10.1180/0009855023740069.
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AbstractSoil kaolins from Indonesia and Western Australia and a range of reference kaolins were studied using Mössbauer spectroscopy, electron paramagnetic resonance (EPR) spectroscopy and SQUID magnetometry. Mössbauer spectra indicate that the Fe within the kaolins is in the highspin Fe3+oxidation state and that a large fraction of the Fe is present as dispersed atoms residing within the octahedral sites of the kaolinite crystal structure. The EPR spectra are typical for soil kaolins except for the absence of radiation-induced defects for the Indonesian kaolins. The Fe(I)spectra are dominant with a strong symmetric peak atg= 4.3, the presence of Fe(II) spectra is shown by a shoulder on this peak atg= 4.9 and a small phase up peak atg= 9.2.Low-temperature (5 K) magnetization (M) measurements over large field (H) sweeps (±70 kOe) yieldedM(H) curves which are fitted well with Brillouin functions indicating the paramagnetic nature of the kaolins at temperatures down to 5 K. A very small remanent magnetization was detectable in the kaolins. Remanent magnetization to saturation magnetization ratios ranged from 10–4to 10–3for the Indonesian kaolins and were all ∼10–3for the Western Australian kaolins, indicating that at high fields the vast majority of the magnetization of the kaolins is due to paramagnetic ions.Zero-field-cooled and field-cooled magnetization measurements in small fields (500 Oe) indicate that the Indonesian kaolins are generally free from magnetically-blocked material down to a temperature of 5 K. The magnetic susceptibility of the Indonesian kaolins shows Curie Law behaviour indicating paramagnetic behaviour over all temperatures down to 5 K. Measurements on the Western Australian kaolins indicated the presence of some magnetic material that is magnetically blocked at temperatures below ∼200 250 K. As a consequence, the magnetic susceptibility showed large deviations from Curie Law behaviour.
Dissertations / Theses on the topic "Soil salinization – Western Australia"
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Horsnell, Tara Kathleen. "Quantifying thresholds for native vegetation to salinity and waterlogging for the design of direct conservation approaches." University of Western Australia. School of Environmental Systems Engineering, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0082.
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A field-based project was undertaken to develop and test a mechanism which would allow for the correlation of the health of vegetation surrounding playa lakes in south-west Australia with the natural variation in salinity and waterlogging that occurs spatially and temporally in natural systems. The study was designed to determine threshold ranges of vegetation communities using moderately extensive data over short temporal periods which will guide the design of potential engineering solutions that manipulate hydrological regimes to ultimately conserve and protect native vegetation. A pair of playa lake ecosystems, surrounded by primary production land, was modelled with hydro-geological data collected from March 2006 to March 2007. The data was used to determine the hydroperiods of vegetation communities fringing playa lakes and provide insight into the areas and species that are most affected by extreme rainfall events which are hypothesised to have a significant, rapid deleterious effect on the ecosystems. The methodology was multi-faceted and included; a detailed topographical survey; vegetation surveys; hydrological and hydro-geological monitoring over a 12 month period. 4 The hydro-geological data and vegetation data was linked with the topographical survey at a high resolution for spatial analysis in a Geographic Information System (GIS) to determine the degree of waterlogging experienced by vegetation communities over the monitoring period. The study has found that the spatial and temporal variability of hydroperiods has been reduced by rising groundwater levels, a result of extensive clearing of native vegetation. Consequently populations are becoming extinct locally resulting in a shift in community composition. Extreme summer rainfall events also have a significant impact on the health of vegetation communities by increasing the duration of waterlogging over an annual cycle and in some areas expanding the littoral zone. Vegetation is most degraded at lower positions in the landscape where communities are becoming less diverse and dominated by salt tolerant halophytic species as a result of altered hydrological regimes. Some species appear to be able to tolerate groundwater depths of less than 2.0 m from the surface, however there are thresholds related to the duration at which groundwater is maintained at this depth. Potential engineering solutions include groundwater pumping and diverting water through drains to maintain sustainable hydroperiods for vegetation in areas with conservation value. The effectiveness and efficiency of the engineering solutions can be maximised by quantifying thresholds for vegetation that include sustainable durations of waterlogging. The study has quantified tolerance ranges to salinity and waterlogging with data collected over 12 months but species may be experiencing a transition period where they have 5 sustained irreversible damage that will result in their eventual mortality. With long-term monitoring, the methodology developed and tested in the study can be used to quantify the long-term tolerance ranges that are important for the application of conservation approaches that include engineering solutions.
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Speldewinde, Peter Christiaan. "Ecosystem health : the relationship between dryland salinity and human health." University of Western Australia. School of Population Health, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0127.
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Australia is experiencing widespread ecosystem degradation, including dryland salinity, erosion and vegetation loss. Approximately 1 million hectares (5.5%) of the south-west agricultural zone of Western Australia is affected by dryland salinity and is predicted to rise to 5.4 million hectares by 2050. Such degradation is associated with many environmental outcomes that may impact on human health, including a decrease in primary productivity, an increase in the number of invasive species, a decrease in the number of large trees, overall decrease in biodiversity, and an increase in dust production. The resulting degradation affects not only farm production but also farm values. This study examines the effects of such severe and widespread environmental degradation on the physical and mental health of residents. Western Australia has an extensive medical record database which links individual health records for all hospital admissions, cancer cases, births and deaths. For the 15 diseases examined in this project, the study area of the south west of Western Australia (excluding the capital city of Perth) contained 1,570,985 morbidity records and 27,627 mortality records for the 15 diseases examined in a population of approximately 460,000. Environmental data were obtained from the Western Australian Department of Agriculture?s soil and landscape mapping database. A spatial Bayesian framework was used to examine associations between these disease and environmental variables. The Bayesian model detected the confounding variables of socio-economic status and proportion of the population identified as Aboriginal or Torres Strait Islander. With the inclusion of these confounders in the model, associations were found between environmental degradation (including dryland salinity) and several diseases with known environmentally-mediated triggers, including asthma, ischaemic heart disease, suicide and depression. However, once records of individuals who had been diagnosed with coexistent depression were removed from the analysis, the effect of dryland salinity was no longer statistically detectable for asthma, ischaemic heart disease or suicide, although the effects of socio-economic status and size of the Aboriginal population remained. The spatial component of this study showed an association between land degradation and human health. These results indicated that such processes are driving the degree of psychological ill-health in these populations, although it remains uncertain whether this 4 is secondary to overall coexisting rural poverty or some other environmental mechanism. To further investigate this complex issue an instrument designed to measure mental health problems in rural communities was developed. Components of the survey included possible triggers for mental health, including environmental factors. The interview was administered in a pilot study through a telephone survey of a small number of farmers in South-Western Australia. Using logistic regression a significant association between the mental health of male farmers and dryland salinity was detected. However, the sample size of the survey was too small to detect any statistically significant associations between dryland salinity and the mental health of women. The results of this study indicate that dryland salinity, as with other examples of ecosystem degradation, is associated with an increased burden of human disease.
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Jardine, Andrew. "The impact of dryland salinity on Ross River virus in south-western Australia : an ecosystem health perspective." University of Western Australia. School of Population Health, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0182.
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[Truncated abstract] A functional ecosystem is increasingly being recognised as a requirement for health and well being of resident human populations. Clearing of native vegetation for agriculture has left 1.047 million hectares of south-west Western Australia affected by a severe form of environmental degradation, dryland salinity, characterised by secondary soil salinisation and waterlogging. This area may expand by a further 1.7-3.4 million hectares if current trends continue. Ecosystems in saline affected regions display many of the classic characteristics of Ecosystem Distress Syndrome (EDS). One outcome of EDS that has not yet been investigated in relation to dryland salinity is adverse human health implications. This thesis focuses on one such potential adverse health outcome: increased incidence of Ross River virus (RRV), the most common mosquito-borne disease in Australia. Spatial analysis of RRV notifications did not reveal a significant association with dryland salinity. To overcome inherent limitations with notification data, serological RRV antibody prevalence was also investigated, and again no significant association with dryland salinity was detected. However, the spatial scale imposed limited the sensitivity of both studies. ... This thesis represents the first attempt to prospectively investigate the influence of secondary soil salinity on mosquito-borne disease by combining entomological, environmental and epidemiological data. The evidence collected indicates that RRV disease incidence is not currently a significant population health priority in areas affected by dryland salinity despite the dominant presence of Ae. camptorhynchus. Potential limiting factors include; local climatic impact on the seasonal mosquito population dynamics; vertebrate host distribution and feeding behaviour of Ae. camptorhynchus; and the scarce and uneven human population distribution across the region. However, the potential for increased disease risk in dryland salinity affected areas to become apparent in the future cannot be discounted, particularly in light of the increasing extent predicted to develop over coming decades before any benefits of amelioration strategies are observed. Finally, it is important to note that both dryland salinity and salinity induced by irrigation are important forms of environmental degradation in arid and semi-arid worldwide, with a total population of over 400 million people. Potential health risks will of course vary widely across different regions depending on a range of factors specific to the local region and the complex interactions between them. It is therefore not possible to make broad generalisations. The need is highlighted for similar research in other regions and it is contended that an ecosystem health framework provides the necessary basis for such investigations.
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Biddle, Dean Leslie. "Investigation of water-mineral interactions in gneissic terrain at Mt. Crawford, South Australia." Title page, contents and abstract only, 1995. http://web4.library.adelaide.edu.au/theses/09PH/09phb584.pdf.
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Diskette for IBM/PC in pocket on back end paper. Copies of author's previously published articles inserted. Bibliography: leaves 186-207. An evaluation of spatial and temporal variation in composition of soil solutions collected from a hydro-toposequence with seasonally saturated soils ranging from Xeralfs to Aqualfs. The sub-catchment is under native eucalyptus and is formed from granite gneiss. The study shows that mineral weathering under eucalypt vegetation contributes substantially to the quantity of elements measured in soil solution with some aeolian salts. Migration of soil solutions to low lying areas promotes dryland salinity in these landscapes.
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Morgan, Karina School of Biological Earth & Environmental Sciences UNSW. "Evaluation of salinisation processes in the Spicers Creek catchment, central west region of New South Wales, Australia." Awarded by:University of New South Wales. School of Biological, Earth and Environmental Sciences, 2005. http://handle.unsw.edu.au/1959.4/24327.
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Spicers Creek catchment is located approximately 400 km west of Sydney in the Central West region of New South Wales, Australia. Dryland salinity has been recognised as a major environmental issue impacting soil and water resources in the Central West region of NSW for over 70 years. Due to the geological complexity of the catchment and the presence of high salt loads contained within the soils, groundwater and surface waters, the Spicers Creek catchment was identified as a large contributor of salinity to the Macquarie River catchment. Over fifty-two dryland salinity occurrences have been identified in the Spicers Creek catchment and it appears that dryland salinity is controlled by the presence of geological structures and permeability contrasts in the shallow aquifer system. Combinations of climatic, geological and agricultural factors are escalating salinity problems in the catchment. The main aim of this thesis was to identify the factors affecting salinisation processes in the Spicers Creek catchment. These include the role of geological structures, the source(s) of salts to the groundwater system and the geochemical processes influencing seepage zone development. To achieve these aims a multidisciplinary approach was untaken to understand the soils, geology, hydrogeology and hydrogeochemistry of the catchment. Investigative techniques employed in this project include the use of geophysics, soil chemistry, soil spectroscopy, hydrogeochemistry and environmental isotopes. Evaluation of high-resolution airborne magnetics data showed a major north-east to south-west trending shear zone. This structure dissects the catchment and several other minor faults were observed to be splays off this major structure. These structures were found to be conducive to groundwater flow and are influencing the groundwater chemistry in the fractured aquifer system. Two distinctive groundwater chemical types were identified in the catchment; the saline Na(Mg)-Cl-rich groundwaters associated with the fractured Oakdale Formation and the Na-HCO3-rich groundwaters associated with the intermediate groundwater system. The groundwater chemistry of other deep groundwaters in the catchment appears to be due to mixing between these end-member groundwaters within the fractured bedrock system. The spatial distribution of electrical conductivity, Cl-, Sr2+ and 87Sr/86Sr isotopic ratios showed the correlation between saline groundwaters and the location of faults. Elevated salinities were associated with the location of two crosscutting fault zones. The spatial distribution of HCO3-, K+, Li+ and ?????3CDIC highlighted the extent of Na-HCO3-rich groundwaters in the catchment and showed that these groundwaters are mixing further east than previously envisaged. These findings show that Na(Mg)-Cl-rich groundwaters are geochemically distinctive and have evolved due to extensive water-rock interaction processes within the fracture zones of the Oakdale Formation. These saline groundwaters contain elevated concentrations of trace elements such as As, V and Se, which pose a potential risk for water resources in the area. 87Sr/86Sr isotopic ratios indicated that the source of salinity to the Na(Mg)-Cl-rich groundwaters was not purely from marine or aerosol input. Salt is most likely contributed from various allochthonous and autochthonous sources. This research found that the main mechanism controlling the formation of dryland salinity seepage zones in the Spicers Creek catchment is due to the presence of geological structures. These groundwater seepage zones act as mixing zones for rainfall recharge and deeper groundwaters. The main sources of salt to the seepage zones are from deeper Na(Mg)-Cl-rich groundwaters and rainfall accession. The major importance of this research highlights the need for an integrated approach for the use of various geoscientific techniques in dryland salinity research within geologically complex environments.
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Graham, Tennille. "Economics of protecting road infrastructure from dryland salinity in Western Australia." University of Western Australia. School of Agricultural and Resource Economics, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0207.
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[Truncated abstract] The salinisation of agricultural land, urban infrastructure and natural habitat is a serious and increasing problem in southern Australia. Government funding has been allocated to the problem to attempt to reduce substantial costs associated with degradation of agricultural and non-agricultural assets. Nevertheless, Government funding has been small relative to the size of the problem and therefore expenditure needs to be carefully targeted to interventions that will achieve the greatest net benefits. For intervention to be justified, the level of salinity resulting from private landholder decisions must exceed the level that is optimal from the point of view of society as a whole, and the costs of government intervention must be less than the benefits gained by society. This study aims to identify situations when government intervention is justified to manage dryland salinity that threatens to affect road infrastructure (a public asset). A key gap in the environmental economics literature is research that considers dryland salinity as a pollution that has off-site impacts on public assets. This research developed two hydrological/economic models to achieve this objective. The first was a simple economic model representing external costs from dryland salinity. This model was used to identify those variables that have the biggest impact on the net-benefits possible from government intervention. The second model was a combined hydro/economic model that represents the external costs from dryland salinity on road infrastructure. The hydrological component of the model applied the method of metamodelling to simplify a complex, simulation model to equations that could be easily included in the economic model. The key variables that have the biggest impact on net-benefits of dryland salinity mitigation were the value of the off-site asset and the time lag before the onset of dryland salinity in the absence of intervention. ... In the case study of dryland salinity management in the Date Creek subcatchment of Western Australia, the economics of vegetation-based and engineering strategies were investigated for road infrastructure. In general, the engineering strategies were more economically beneficial than vegetation-based strategies. In the case-study catchment, the cost of dryland salinity affecting roads was low relative to the cost to agricultural land. Nevertheless, some additional change in land management to reduce impacts on roads (beyond the changes justified by agricultural land alone) was found to be optimal in some cases. Reinforcing the results from the simple model, a key factor influencing the economics of dryland salinity management was the urgency of the problem. If costs from dryland salinity were not expected to occur until 30 years or more, the optimal response in the short-term was to do nothing. Overall, the study highlights the need for governments to undertake comprehensive and case-specific analysis before committing resources to the management of dryland salinity affecting roads. There were many scenarios in the modelling analysis where the benefits of interventions would not be sufficient to justify action.
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Pritchard, Deborah Leeanne. "Phosphorus bioavailability from land-applied biosolids in south-western Australia." Curtin University of Technology, Muresk Institute, 2005. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=16492.
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The annual production of biosolids in the Perth region during the period of this study was approximately 13,800 t dry solids (DS), being supplied by three major wastewater treatment plants. Of this, 70% was typically used as a low-grade fertiliser in agriculture, representing an annual land use area of around 1,600 ha when spread between 5 and 7 t DS/ha. Loading rates of biosolids are typically based on the nitrogen (N) requirements of the crop to be grown, referred to as the N Limiting Biosolids Application Rate (NLBAR). A consequence of using the NLBAR to calculate loading rates is that phosphorus (P) is typically in excess of plant requirement. The resultant high loading rates of P are considered in the guidelines developed for the agricultural use of biosolids in Western Australia, but lack research data specific to local conditions and soil types. Regulatory changes throughout Australia and globally to protect the environment from wastewater pollution have created a need for more accountable and balanced nutrient data. Experiments presented in this thesis were undertaken to ascertain: the percentage relative effectiveness (RE) of biosolids as a source of plant available P compared with inorganic P fertiliser; loading rates to best supply P for optimum crop growth; P loading rates of risk to the environment; and the forms of P in local biosolids. Therefore, both the agronomic and environmental viewpoints were considered. Anaerobically digested and dewatered biosolids produced from Beenyup Wastewater Treatment Plant, Perth with a mean total P content of 2.97% dry weight basis (db) were used in a series of glasshouse, field and laboratory experiments. The biosolids were sequentially fractionated to identify the forms of P present and likewise in soil samples after applying biosolids or monocalcium phosphate (MCP).The biosolid P was predominantly inorganic (92%), and hence the organic fraction (8%) available for mineralisation at all times would be extremely low. The most common forms of biosolid P were water-soluble P and exchangeable inorganic P (66%), followed by bicarbonate extractable P (19%) and the remaining P as inorganic forms associated with Fe, Al and Ca (14%). Following the application of biosolids to a lateritic soil, the Fe and Al soil fractions sorbed large amounts of P, not unlike the distribution of P following the addition of MCP. Further investigation would be required to trace the cycling of biosolid P in the various soil pools. The growth response of wheat (Triticum aestivum L.) to increasing rates of biosolids and comparable rates of inorganic P as MCP, to a maximum of 150 mg P/kg soil was examined in the glasshouse. The percentage relative effectiveness (RE) of biosolids was calculated using fitted curve coefficients from the Mitscherlich equation: y = a (1-b exp–cx) for dry matter (DM) production and P uptake. The initial effectiveness of biosolid P was comparable to that of MCP with the percentage RE of biosolids averaging 106% for DM production of wheat shoots and 118% for shoot P uptake at 33 days after sowing (DAS) over three consecutive crops. The percentage residual value (RV) declined at similar rates for DM production in MCP and biosolids, decreasing to about 33% relative to freshly applied MCP in the second crop and to approximately 16% in the third crop. The effectiveness of biosolid P was reduced significantly compared with inorganic P when applied to a field site 80 km east of Perth (520 mm annual rainfall). An infertile lateritic podsolic soil, consistent with the glasshouse experiment and representative of a soil type typically used for the agricultural application of biosolids in Western Australia was used.
Increasing rates of biosolids and comparable rates of triple superphosphate (TSP), to a maximum of 145 kg P/ha were applied to determine a P response curve. The percentage RE was calculated for seasonal DM production, final grain yield and P uptake in wheat followed by lupin (Lupinus angustifolius L.) rotation for the 2001 and 2002 growing seasons, respectively. In the first year of wheat, the RE for P uptake in biosolids compared with top-dressed TSP ranged from 33% to 55% over the season and by grain harvest was 67%. In the second year, and following incorporation with the disc plough at seeding, the RE for P uptake by lupins in biosolids averaged 79% over the growing season compared with top-dressed TSP, and by grain harvest the RE was 60%. The residual value (RV) of lupins at harvest in biosolids compared with freshly applied TSP was 47%. The non-uniform placement of biosolids (i.e. spatial heterogeneity) was primarily responsible for the decreased ability of plant roots to absorb P. The P was more effective where biosolids were finely dispersed throughout the soil, less so when roughly cultivated and least effective when placed on the soil surface without incorporation. The RE for grain harvest of wheat in the field decreased from 67% to 39% where biosolids were not incorporated (i.e. surface-applied). The RE could also be modified by factors such as soil moisture and N availability in the field, although it was possible to keep these variables constant in the glasshouse. Consequently, absolute values determined for the RE need to be treated judiciously. Calculations showed that typical loading rates of biosolids required to satisfy agronomic P requirements of wheat in Western Australia in the first season could vary from 0 to 8.1 t DS/ha, depending on soil factors such as the P Retention Index (PRI) and bicarbonate available P value.
Loading rates of biosolids were inadequate for optimum P uptake by wheat at 5 t DS/ha (i.e. 145 kg P/ha) based on the NLBAR on high P sorbing soils with a low fertiliser history (i.e. PRI >15, Colwell bicarbonate extractable P <15 mg P/kg). On soils of PRI <2 mL/g however, biosolids applied at identical loading rates would result in high concentrations of available P. Further work on sites not P deficient would be necessary to validate these findings on farmed soils with a regular history of P fertiliser. The sieving of soil samples used in the field experiment to remove stones and coarse organic matter prior to chemical analysis inadvertently discarded biosolids particles >2 mm, and thus their was little relationship between soil bicarbonate extractable P and P uptake by plants in the field. The risk of P leaching in biosolids-amended soil was examined over a number of different soil types at comparable rates of P at 140 mg P/kg (as either biosolids or MCP) in a laboratory experiment. Given that biosolids are restricted on sites prone to water erosion, the study focussed on the movement of water-soluble P by leaching rather than by runoff of water-soluble P and particulate P. In general the percentage soluble reactive P recovered was lower in soils treated with biosolids than with MCP, as measured in leachate collected using a reverse soil leachate unit. This was particularly evident in acid washed sand with SRP measuring 14% for biosolids and 71% for MCP, respectively, although the differences were not as large in typical agricultural soils. Specific soil properties, such as the PRI, pH, organic carbon and reactive Fe content were negatively correlated to soluble reactive P in leachate and thus reduced the risk of P leaching in biosolids-amended soil.
Conversely, the total P and bicarbonate extractable P status of the soils investigated were unreliable indicators as to the amount of P leached. On the basis of the experiments conducted, soils in Western Australia were categorised according to their ability to minimise P enrichment and provide P necessary for crop growth at loading rates determined by the NLBAR. Biosolids applied at the NLBAR to soils of PRI >2mL/g with reactive Fe >200 mg/kg were unlikely to necessitate P loading restrictions. Although specific to anaerobically digested biosolids cake applied to Western Australian soils, the results will be of relevance to any industry involved in the land application of biosolids, to prevent P contamination in water bodies and to make better use of P in crop production.
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Bari, Mohammed A. "A distributed conceptual model for stream salinity generation processes : a systematic data-based approach." University of Western Australia. School of Earth and Geographical Sciences, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0058.
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[Truncated abstract] During the last fifty years mathematical models of catchment hydrology have been widely developed and used for hydrologic forecasting, design and water resources management. Most of these models need large numbers of parameters to represent the flow generation process. The model parameters are estimated through calibration techniques and often lead to ‘unrealistic’ values due to structural error in the model formulations. This thesis presents a new strategy for developing catchment hydrology models for representing streamflow and salinity generation processes. The strategy seeks to ‘learn from data’ in order to specify a conceptual framework that is appropriate for the particular space and time scale under consideration. Initially, the conceptual framework is developed by considering large space and time scales. The space and time scales are then progressively reduced and conceptual model complexity systematically increased until ultimately, an adequate simulation of daily streamflow and salinity is achieved. This strategy leads to identification of a few key physically meaningful parameters, most of which can be estimated a priori and with minimal or no calibration. Initially, the annual streamflow data from ten experimental catchments (control and cleared for agriculture) were analysed. The streamflow increased in two phases: (i) immediately after clearing due to reduced evapotranspiration, and (ii) through an increase in stream zone saturated area. The annual evapotranspiration losses from native vegetation and pasture, the ‘excess’ water (resulting from reduced transpiration after land use change), runoff and deep storage were estimated by a simple water balance model. The model parameters are obtained a priori without calibration. The annual model was then elaborated by analysing the monthly rainfall-runoff, groundwater and soil moisture data from four experimental catchments. Ernies (control, fully forested) and Lemon (53% cleared) catchments are located in zone with a mean annual rainfall of 725 mm. Salmon (control, fully forested) and Wights (100% cleared) are located in zone with mean annual rainfall of 1125 mm. Groundwater levels rose and the stream zone saturated area increased significantly after clearing. From analysis of this data it was evident that at a monthly time step the conceptual model framework needed to include a systematic gain/loss to storage component in order to adequately describe the observed lags between peak monthly rainfall and runoff.
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Doole, Graeme John. "Value of perennial pasture phases in dryland agricultural systems of the eastern-central wheat belt of Western Australia." University of Western Australia. School of Agricultural and Resource Economics, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0213.
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Over the past thirty years, price relativities and technological development have motivated an increase in the area of land allocated to cropping, as opposed to pasture production, throughout the central wheat belt of Western Australia. Nevertheless, reducing the proportion of pasture in these rotations has challenged the future productivity of farming systems in this area. First, the frequent application of selective herbicides for weed control in extended cropping rotations has promoted the development of herbicide resistance in a number of major agricultural weeds. Second, the primary use of annual plants has promoted the development of soil salinisation by allowing a significant proportion of rainfall to recharge saline water tables. The inclusion of perennial pasture phases between extended periods of cropping may mitigate or delay these constraints to production through (a) allowing the use of costeffective forms of non-selective weed control, and (b) through creating a buffer of dry soil that absorbs leakage occurring beneath subsequent crops. This study consequently explores the value of including perennial pasture phases in dryland agricultural systems in the eastern-central wheat belt of Western Australia, accounting for benefits related to herbicide resistance and water table management. A novel computational algorithm for the solution of multiple-phase optimal control problems is developed and used to conduct a conceptual analysis of the value of lucerne (Medicago sativa L.) pasture for managing annual ryegrass (Lolium rigidum Gaudin), the primary weed in wheat belt cropping systems. The competitiveness and fecundity of annual ryegrass provide strong economic incentives to maintain a low weed population, irrespective of herbicide-resistance status. Consequently, the ineffectiveness of selective herbicides primarily reduces the profitability of cropping by motivating the adoption of more costly non-selective forms of weed control. The inclusion of lucerne in land-use rotations is only optimal in the presence of severe herbicide resistance given (a) the low efficiency of alternative weed-management practices available during the pasture phase, relative to selective-herbicide application; (b) the significant cost of establishing this perennial pasture; and (c) the high relative profitability of cereal production in the absence of resistance. The value of lucerne, relative to annual pastures, for weed management is explored in greater detail through the use of compressed annealing to optimise a sophisticated simulation model. The profitability of candidate rotations is also manipulated to account for the long-term production losses accruing to the recharge of saline groundwaters that occurs beneath them. Sequences incorporating lucerne are only more profitable than those that include annual pasture at the standard set of parameter values if (a) annual ryegrass is resistant to all selective herbicides, (b) the water table is so shallow (approximately less than 3.5 m deep) that frequent rotation with perennials is required to avert soil salinisation, or (c) sheep production is highly profitable. The value of perennial pasture is sufficient under these circumstances to overcome its high establishment cost. Consistent with intuition, these benefits are reinforced by lower discount rates and higher rates of leakage occurring beneath annual-based systems. Formulation of an effective communication strategy to report these results to producers is justified given the complexity involved in determining the true magnitude of these intertemporal benefits through alternative means, such as field trials.
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Swarts, Derek Juan. "Soil community structure and litter decomposition under irrigated Eucalyptus Globulus in South Western Australia." Connect to thesis, 2006. http://portal.ecu.edu.au/adt-public/adt-ECU2006.0051.html.
Full textBooks on the topic "Soil salinization – Western Australia"
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Western Australia. Parliament. Legislative Council. Select Committee on Salinity. Report on salinity in Western Australia: First report. [Western Australia: s.n., 1988.
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Western Australia. Parliament. Legislative Council. Select Committee on Salinity. Report on salinity in Western Australia: Final report and recommenations. [W.A.]: Parliament of Western Australia, Legislative Council, 1988.
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Research for Development Seminar (1984 Cunderdin, W.A.). Forage and fuel production from salt affected wasteland: Proceedings of a seminar held at Cunderdin, Western Australia, 19-27 May, 1984. Amsterdam: Elsevier, 1986.
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Deep Drainage Taskforce (W.A.). Deep drainage in south-west Western Australia: Making it work, not proving it wrong : report and recommendations to the Honourable Monty House MLA, Minister for Primary Industry and Fisheries. South Perth, WA: Agriculture W.A. for the Taskforce, 2000.
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Supply, Western Australia Steering Committee for Research on LandUse and Water. Stream salinity and its reclamation in south-west Western Australia. Leederville, WA: Water Authority of Western Australia, Water Resources Directorate, 1989.
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Belitz, Kenneth. Simulation of water-table response to management alternatives, central part of the western San Joaquin Valley, California. Sacramento, Calif: U.S. Dept. of the Interior, U.S. Geological Survey, 1994.
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Belitz, Kenneth. Simulation of water-table response to management alternatives, central part of the western San Joaquin Valley, California. Sacramento, Calif: U.S. Dept. of the Interior, U.S. Geological Survey, 1992.
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Belitz, Kenneth. Simulation of water-table response to management alternatives, central part of the western San Joaquin Valley, California. Sacramento, Calif: U.S. Dept. of the Interior, U.S. Geological Survey, 1992.
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Belitz, Kenneth. Simulation of water-table response to management alternatives, central part of the western San Joaquin Valley, California. Sacramento, Calif: U.S. Dept. of the Interior, U.S. Geological Survey, 1992.
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Belitz, Kenneth. Simulation of water-table response to management alternatives, central part of the western San Joaquin Valley, California. Sacramento, Calif: U.S. Dept. of the Interior, U.S. Geological Survey, 1994.
Find full textBook chapters on the topic "Soil salinization – Western Australia"
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Connell, Karen. "Marketing soil acidity knowledge in Western Australia." In Plant-Soil Interactions at Low pH: Principles and Management, 717–21. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0221-6_114.
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Cudahy, T., M. Jones, M. Thomas, P. Cocks, F. Agustin, M. Caccetta, R. Hewson, M. Verrall, and A. Rodger. "Mapping Soil Surface Mineralogy at Tick Hill, North-Western Queensland, Australia, Using Airborne Hyperspectral Imagery." In Proximal Soil Sensing, 211–29. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-8859-8_18.
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Bloom, L. M., and D. J. Kentwell. "A Geostatistical Analysis of Cropped and Uncropped Soil from the Jimperding Brook Catchment of Western Australia." In geoENV II — Geostatistics for Environmental Applications, 369–79. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-015-9297-0_31.
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Fraser, David. "Mapping Areas Susceptible to Soil Salinity in the Irrigation Region of Southern New South Wales, Australia." In Remote Sensing of Soil Salinization. CRC Press, 2008. http://dx.doi.org/10.1201/9781420065039.pt2.
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Holmes, K., N. Odgers, E. Griffin, and D. van Gool. "Spatial disaggregation of conventional soil mapping across Western Australia using DSMART." In GlobalSoilMap, 273–79. CRC Press, 2014. http://dx.doi.org/10.1201/b16500-51.
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Khan, A., and H. R. Nikraz. "Evaluation of ground movement using a simple soil suction technique in Western Australia." In Unsaturated Soils for Asia, 687–92. CRC Press, 2020. http://dx.doi.org/10.1201/9781003078616-121.
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Chalmer, Nicole Y. "Brumbies (Equus ferus caballus) as Colonizers of the Esperance Mallee–Recherche Bioregion in Western Australia." In Environments of Empire, 197–223. University of North Carolina Press, 2020. http://dx.doi.org/10.5149/northcarolina/9781469655932.003.0010.
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Before Australia was taken over by humans more than 55 000 years BP, the landscapes were shaped through animal agency. Extinct prehistoric fauna and megafauna had social ecological systems and actively organized ecosystems and landscapes that reflected patterns of herbivory, soil foraging, nutrient cycling and predation. Surviving species continued as agents in the ecosystem functions of the EM-R region until the beginning of European colonization in the 1860’s. The settlers used the inherent biological traits of their domesticated animals, including horses, as an agency of colonization. Horses (Equus ferus caballus) who escaped to become wild are known as Brumbies in the Australian vernacular. They adapted to the local environments and prospered. This chapter analyzes the ways Brumbies have adapted to and made the land their own. It shows how they became intimately engaged with landscape details and resources which are reflected through their creation of cultural horsetrails as they moved purposefully throughout their homelands.
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Maltman, Alex. "Weathering, Soil, and the Minerals in Wine." In Vineyards, Rocks, and Soils. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190863289.003.0014.
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Weathering of rocks is the crucial first step in making vineyards possible. For where the debris produced by weathering—the sediment we met in Chapter 5—becomes mixed with moist humus, it will be capable of supporting higher plant life. And thus we have soil, that fundamental prerequisite of all vineyards, indeed of the world’s agriculture. So how does this essential process of weathering come about? Any bare rock at the Earth’s surface is continually under attack. Be it a rocky cliff, a stone cathedral, or a tombstone, there will always be chemical weathering—chemical reactions between its surface and the atmosphere A freshly hewn block of building stone may look indestructible, but before long it will start to look a bit discolored and its surface a little crumbly. We are all familiar with an analogy of this: a fresh surface of iron or steel reacting with moisture and oxygen in the air to form the coating we call rust. In his “Guide to the Lakes” of England, William Wordsworth put the effects of weathering far more picturesquely: “elementary particles crumbling down, over-spread with an intermixture of colors, like the compound hues of a dove’s neck.” A weathered rock is one that is being weakened, broken down. The rock fragments themselves are further attacked, which is why stones in a vineyard often show an outer coating of discolored material, sometimes referred to as a weathering rind (Figure 9.1; see Plate 22). If the stone is broken open, it may show multiple zones of differing colors paralleling the outer surface of the fragment and enclosing a core of fresh rock. Iron minerals soon weather to a powdery combination of hematite, goethite, and limonite, and the rock takes on a reddish-brown, rusty-looking color. The great example of such weathering in viticulture is the celebrated terra rossa, but the rosy soils in parts of Western Australia and places further east such as McLaren Vale and the Barossa Valley are also due to iron minerals. Several Australian wines take their names from this “ironstone.”
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White, Robert E. "Putting it All Together." In Understanding Vineyard Soils. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780199342068.003.0009.
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In reality, there can be no generic definition of an “ideal soil” because a soil’s performance is influenced by the local climate, landscape characteristics, grape variety, and cultural practices and is judged in the context of a winegrower’s objectives for style of wine to be made, market potential, and profitability of the enterprise. This realization essentially acknowledges the long-established French concept of terroir: that the distinctiveness or typicity of wines produced in individual locations depends on a complex interaction of biophysical and human cultural factors, interpreted by many as meaning a wine’s sense of place. As discussed in “Soil Variability and the Concept of Terroir” in chapter 1, because of this interaction of factors that determine a particular terroir, it is not surprising that no specific relationships between one or more soil properties and wine typicity have been unequivocally demonstrated. While acknowledging this conclusion, it is still worthwhile to examine how variations in several single or combined soil properties can influence vine performance and fruit character. These properties are: • Soil depth • Soil structure and water supply • Soil strength • Soil chemistry and nutrient supply • Soil organisms Provided there are no subsoil constraints, the natural tendency of long-lived Vitis vinifera, on own roots or rootstocks, to root deeply and extensively gives it access to a potentially large store of water and nutrients. In sandy and gravely soils that are naturally low in nutrients, such as in the Médoc region of France, the Margaret River region in Western Australia, and the Wairau River plain, Marlborough region, New Zealand, the deeper the soil the better. A similar situation pertains on the deep sandy soils on granite in the Cauquenas region, Chile. However, such depth may be a disadvantage where soils are naturally fertile and rain is plentiful, as in parts of the Mornington Peninsula, King and Yarra Valley regions, Victoria, Australia, and the Willamette Valley region in Oregon (see figure 1.11, chapter 1), because vine growth is too vigorous and not in balance.
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Culver, David C., and Tanja Pipan. "Some Representative Subterranean Communities." In The Biology of Caves and Other Subterranean Habitats, 206–25. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198820765.003.0009.
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Among shallow subterranean habitats, representative communities of hypotelminorheic (Lower Potomac seeps, Washington, DC), epikarst (Postojna–Planina Cave System, Slovenia), milieu souterrain superficiel (MSS) (central Pyrenees, France), soil (central Pyrenees, France), calcrete aquifers (Pilbara, Western Australia), lava tubes (Tenerife, Spain and Lava Beds National Monument, California), fluvial aquifers (Lobau wetlands, Austria), and iron-ore caves (Brazil) are described. Among non-cave deeper habitats, communities of phreatic aquifers (Edwards Aquifer, Texas), and deep phreatic aquifers (basalt aquifers, Washington) are described. Among cave habitats, representative tropical terrestrial (Gua Salukkan Kallang, Sulawesi, Indonesia), temperate terrestrial (Mammoth Cave, Kentucky), chemoautotrophic (Peştera Movile, Romania), hygropetric (Vjetrenica, Bosnia & Herzegovina), anchialine (Šipun, Croatia), cave streams (West Virginia and U.K.) and springs (Las Hountas, Baget basin, France) communities are discussed.
Conference papers on the topic "Soil salinization – Western Australia"
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Do, Peerapong, Hamid Nikraz, and Supat Chummuneerat. "Soil Stabilisation for Road Pavements Towards Western Australia Experience." In International Conference on Ground Improvement & Ground Control. Singapore: Research Publishing Services, 2012. http://dx.doi.org/10.3850/978-981-07-3560-9_05-0525.
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Kobayashi, Chiaki, Ian C. Lau, Buddy Wheaton, Lindsay Bourke, Satomi Kakuta, and Tetsushi Tachikawa. "Mapping of soil salinity using an airborne hyperspectral sensor in Western Australia." In IGARSS 2015 - 2015 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2015. http://dx.doi.org/10.1109/igarss.2015.7326366.
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Shi, Xianzhong, Mehrooz Aspandiar, and Ian C. Lau. "Assessment of acid sulfate soil using hyperspectral data in South Yunderup, Western Australia." In IGARSS 2013 - 2013 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2013. http://dx.doi.org/10.1109/igarss.2013.6723790.
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Zhu, Yingbo, Quansheng Ge, Jiyuan Liu, Yunxuan Zhou, Zhiqiang Gao, and Siqing Chen. "A case study on the relationship between soil geochemical components and salinization in the western Jilin Province of China." In Optical Science and Technology, the SPIE 49th Annual Meeting, edited by Wei Gao and David R. Shaw. SPIE, 2004. http://dx.doi.org/10.1117/12.559269.
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El-Horiny, Mohamed M. "Mapping and monitoring of soil salinization using remote sensing and regression techniques: a case study in the Bahariya depression, Western Desert, Egypt." In IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2019. http://dx.doi.org/10.1109/igarss40859.2019.8949893.
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Hermon, K., G. Allinson, P. Maher, F. Stagnitti, and R. Armstrong. "Effect of recycled water on the soil physical-chemical properties of four vineyards in Great Western, Victoria, Australia." In WATER POLLUTION 2008. Southampton, UK: WIT Press, 2008. http://dx.doi.org/10.2495/wp080581.
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Hewson, R. D., G. R. Taylor, and L. B. Whitbourn. "Application of TIR Imagery and Spectroscopy for the Extraction of Soil Textural Information at Fowlers Gap, Western New South Wales, Australia." In IGARSS 2008 - 2008 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2008. http://dx.doi.org/10.1109/igarss.2008.4779095.
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Mansour, Alaa M., Brian J. Gordon, Qi Ling, and Qiang Shen. "TLP Survivability Against Progressive Failure of Tendon and Foundation Systems in Offshore Western Australian Harsh Environment." In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-11468.
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In this paper the design robustness of Tension Leg Platform (TLP) tendon and tendon foundation systems of a TLP that is located in offshore Western Australia is investigated. A case study of a TLP that is self-stable (without tendons) has been considered. The study involves the numerical simulation of progressive failure of tendons in cyclonic events. The TLP response during the transition from a restrained TLP with all tendons to the free-floating condition has been numerically simulated. The numerical results from this simulation have been verified against physical model test measurements. The numerical simulation is repeated for a TLP with an optimized hull design that does not maintain stability when all tendons fail. Cost versus benefit in these two cases is quantified and compared. The progressive failure of the TLP Gravity Base Foundation (GBF) system has also been investigated in this paper. One of the potential failure modes for this type of foundation is the loss of suction underneath the foundation. Increasing the amount of solid ballast in the GBF increases the net downward load on the soil and reduces the reliance on the soil suction. Numerical simulations of the progressive loss of suction are performed for two cases; 1) slightly over designed foundation to include extra ballast and 2) optimized foundation design that is highly rely on the soil suction. Again, cost versus benefit in these two cases is presented. The paper provides clear insights supported by calculations and model tests for proposed design robustness that could be built in a TLP design at a relatively small additional cost to address uncertainties associated with designing TLP in offshore Western Australian harsh environment region.
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Mahmoodzadeh, Hamed, Noel Boylan, Mark Randolph, and Mark Cassidy. "The Effect of Partial Drainage on Measurements by a Piezoball Penetrometer." In ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2011. http://dx.doi.org/10.1115/omae2011-50245.
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Full-flow penetrometers such as the T-bar and ball are now widely used in offshore site investigations to measure penetration resistance and then infer the strength properties of the seabed. To provide additional data on flow properties of the soil and increase the number of parameters that can be obtained from these tests, ball penetrometers fitted with pore pressure transducers, known as piezoballs, are now being used. Depending on the soil characteristics and rate of penetration, the soil conditions during penetration may vary from undrained to fully drained. The drainage condition during penetration will influence both the measured penetration resistance and excess pore pressure response and therefore influence any parameters interpreted. This paper examines the effect of drainage condition on piezoball measurements during penetration in a muddy silt sample collected from offshore Australia. Tests were conducted in the beam centrifuge at the University of Western Australia using a miniature piezoball, with pore pressure measurement at the equator position. The effect of drainage condition was examined by conducting tests at various rates of penetration, ranging from undrained to fully drained conditions. Methods of interpreting the results of a partially drained penetration test in order to deduce the undrained penetration resistance are also discussed.
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Hodder, M. S., D. J. White, and M. J. Cassidy. "Centrifuge Modelling of Riser-Soil Stiffness Degradation in the Touchdown Zone of a Steel Catenary Riser." In ASME 2008 27th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/omae2008-57302.
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Steel catenary risers (SCRs) are economical to assemble and install compared to conventional vertical risers. However, accurate evaluation of the fatigue life of an SCR remains a major challenge due to uncertainty surrounding the interaction forces at the seabed within the touchdown zone (TDZ). Fatigue life predictions are heavily dependant on the assumed stiffness between the riser and the seabed and therefore an accurate assessment of seabed stiffness — or more specifically the nonlinear pipe-soil resistance — is required. During the lifespan of an SCR, vessel motions due to environmental loading cause repeated penetration of the riser into the seabed within the TDZ. This behaviour makes assessment of seabed stiffness difficult due to the gross deformations of the seabed and the resulting soil remoulding and water entrainment. This paper describes a model test in which the movement of a length of riser pipe was simulated within the geotechnical beam centrifuge at the University of Western Australia. The model soil was soft, lightly over-consolidated kaolin clay with a linearly increasing shear strength profile with depth, typical of deepwater conditions. The pipe was cycled over a fixed vertical distance from an invert embedment of 0.5 diameters to above the soil surface. This range represents a typical vertical oscillation range of a section of riser within the TDZ during storm loading. The results indicate a significant degradation in the vertical pipe-soil resistance during cyclic vertical movements. Due to the cyclic degradation in soil strength, the component of the vertical resistance created by buoyancy was significant, particularly due to the influence of heave. A new approach to the interpretation of heave-enhanced buoyancy was used to extract the separate influences of soil strength and buoyancy, allowing the cyclic degradation in strength to be quantified. During cycling, the soil strength reduced by a factor of 7.5 relative to the initial penetration stage. This degradation was more significant than the reduction in soil strength during a cyclic T-bar penetration test. This contrast can be attributed to the breakaway of the pipe from the soil surface which allowed water entrainment. This dramatic loss of strength and therefore secant stiffness, and the significance of the buoyancy term in the total vertical pipe-soil resistance, has implications for the fatigue assessment of SCRs.