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1
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.
Testo completoAbstract (sommario):
"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.
2
Shi, Xianzhong. "Hyperspectral sensing of acid sulphate soils and their environmental impacts in South Yunderup, Western Australia". Thesis, Curtin University, 2014. http://hdl.handle.net/20.500.11937/1820.
Testo completoAbstract (sommario):
Several sources of hyperspectral data were used to map the occurrence and spread of acid sulfate soils (AAS). Surface evolution of mineralogy during controlled oxidation of sulphidic material showed the formation of secondary iron minerals linked to soil pH ranges. Spectral characterization, image classification and PLSR of hyperspectral data successfully mapped the occurrence of surface and subsurface acid conditions and related toxicity by linking mineralogy to pH.
3
Harris, Mark Anglin. "Some organic amendments for heavy metal toxicity, acidity and soil structure in acid-sulphate mine tailings /". Title page, contents and abstract only, 2000. http://web4.library.adelaide.edu.au/theses/09PH/09phh3148.pdf.
Testo completo
4
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.
Testo completoAbstract (sommario):
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.
5
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.
Testo completo
6
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.
Testo completo
7
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.
Testo completoAbstract (sommario):
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.
8
Mustafa, Akhmad Biological Earth & Environmental Sciences Faculty of Science UNSW. "Improving acid sulfate soils for brackish water aquaculture ponds in South Sulawesi, Indonesia". Awarded by:University of New South Wales. Biological, Earth & Environmental Sciences, 2007. http://handle.unsw.edu.au/1959.4/40619.
Testo completoAbstract (sommario):
Brackish water aquaculture is one of the largest coastal industries in Indonesia. This farming system involves the construction of ponds m coastal sediments. Many ponds in Indonesia have been abandoned due to past development of ponds in acid 8ulfate soils (ASS); these soils produce sulfuric acid through the oxidation of pyrite du ring and after the sediments have been excavated. The soils also contain elevated concentrations of metal such as iron and aluminium which are harmful to farmed fish and shrimp. Acidification of pond soil causes recurrent fish and shrimp mortalities, poor growth rate in fish and shrimp, soft shell syndrome in shrimp and low plankton densities, Pond maintenance costs in ASS are also significantly higher than non-ASS ponds. There are over 6.7 million ha of ASS In Indonesia of which 35% has been developed for brackish water aquaculture. This study developed and trialled methods of soil remediation to restore abandoned ASS-affected ponds. The main objective was to develop methods at remediation that were scientifically sound but also practical and inexpensive for farmers. The research involved characterising, in detail, the chemical and physical properties of ponds soil followed by laboratory-based experiments to improve soil properties. The results of laboratory trials were the basis for large-scale field experiments to test soil remediation strategies. The study showed that pond bottoms could be improved by forced oxidation, flooding and water exchange followed by Iiming and fertilising. Up to 500% increases in productivity were achieved by this method and soils conditions Improved significantly. A further twofold productivity increase was achieved by an integrated liming method in which lime is added to rebuilt or new dykes in layers. A juvenile shrimp production system was developed for ponds that were too severely degraded or costly to remediate. The research developed methods of preventing metal toxicity in Juvenile shrimp. The study showed that aquaculture ponds built in ASS could be remediated and returned to viable production systems. Importantly, the study has developed a more detailed understanding of chemical properties In ASS-affected ponds.
9
Bagheri, Kazemabad Abdolreza. "Boron tolerance in grain legumes with particular reference to the genetics of boron tolerance in peas". Title page, summary and contents only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phb144.pdf.
Testo completo
10
Shrestha, Hari Ram. "Post-fire recovery of carbon and nitrogen in sub-alpine soils of South-eastern Australia /". Connect to thesis, 2009. http://repository.unimelb.edu.au/10187/6963.
Testo completoAbstract (sommario):
The forests of south-eastern Australia, having evolved in one of the most fire-prone environments in the world, are characterized by many adaptations to recovery following burning. Thus forest ecosystems are characterized by rapid regenerative capacity, from either seed or re-sprouting, and mechanisms to recover nutrients volatilized, including an abundance of N2 fixing plants in natural assemblages. Soil physical, chemical and biological properties are directly altered during fire due to heating and oxidation of soil organic matter, and after fire due to changes in heat, light and moisture inputs. In natural ecosystems, carbon (C) and nitrogen (N) lost from soil due to fires are recovered through photosynthesis and biological N2 fixation (BNF) by regenerating vegetation and soil microbes.This study investigated post-fire recovery of soil C and N in four structurally different sub-alpine plant communities (grassland, heathland, Snowgum and Alpine ash) of south-eastern Australia which were extensively burnt by landscape-scale fires in 2003. The amount and isotopic concentration of C and N in soils to a depth of 20 cm from Alpine ash forest were assessed five years after fire in 2008 and results were integrated with measurements taken immediately prior to burning (2002) and annually afterwards.
Because the historical data set, comprised of three soil samplings over the years 2002 to 2005, consisted of soil total C and N values which were determined as an adjunct to 13C and 15N isotopic studies, it was necessary to establish the accuracy of these IRMS-derived measurements prior to further analysis of the dataset. Two well-established and robust methods for determining soil C (total C by LECO and oxidizable C by the Walkley-Black method) were compared with the IRMS total C measurement in a one-off sampling to establish equivalence prior to assembling a time-course change in soil C from immediately pre-fire to five years post-fire. The LECO and IRMS dry combustion measurements were essentially the same (r2 >0.99), while soil oxidizable C recovery by the Walkley-Black method (wet digestion) was 68% compared to the LECO/IRMS measurements of total C. Thus the total C measurement derived from the much smaller sample size (approximately 15 mg) combusted during IRMS are equivalent to LECO measurement which require about 150 mg of sample.
Both total C and N in the soil of Alpine ash forests were significantly higher than soils from Snowgum, heathland and grassland communities. The ratio of soil NH4+ to NO3- concentration was greater for Alpine ash forest and Snow gum woodland but both N-fractions were similar for heathland and grassland soils. The abundance of soil 15N and 13C was significantly depleted in Alpine ash but both isotopes were enriched in the heathland compared to the other ecosystems. Abundance of both 15N and 13C increased with soil depth.
The natural abundance of 15N and 13C in the foliage of a subset of non-N2 fixing and N2 fixing plants was measured as a guide to estimate BNF inputs. Foliage N concentration was significantly greater in N2 fixers than non-N2 fixers while C content and 13C abundance were similar in both functional groups. Abundance of 15N was depleted in the N2 fixing species but was not significantly different from the non-N2 fixers to confidently calculate BNF inputs based on the 15N abundance in the leaves.
The total C pool in soil (to 20 cm depth) had not yet returned to the pre-fire levels in 2008 and it was estimated that such levels of C would be reached in another 6-7 years (about 12 years after the fire). The C and N of soil organic matter were significantly enriched in 15N and 13C isotopes after fire and had not returned to the pre-fire levels five years after the fire. It is concluded that the soil organic N pool can recover faster than the total C pool after the fire in the Alpine ash forests.
11
George, Suman Jacob. "Effects of land-use change on phosphorus forms in South-West Australian soils". University of Western Australia. School of Earth and Geographical Sciences, 2004. http://theses.library.uwa.edu.au/adt-WU2004.0078.
Testo completoAbstract (sommario):
[Truncated abstract] Eleven sites, each with the trio of land uses: Eucalyptus globulus plantation, pasture and natural vegetation, representing from the Mediterranean climate, high rainfall region (<550 mm annually) of south-western Australia were investigated to assess medium-term changes in the P-supplying capacity of soils in eucalypt plantations growing on agricultural land. The natural vegetation soils were a benchmark for comparing soil P change since land clearing and development for agriculture. The experimental framework provided an ideal basis for studying changes in P forms since land clearing and fertilization for agriculture and the ensuing conversion to plantations (on an average 9 years ago). Conventional soil P indices measure plant available P that is more relevant to short duration annual crops and pastures. To predict medium-term P availability, P forms were determined using Hedley et al.’s (1982) fractionation scheme and fractions were grouped using the Guo and Youst (1998) criteria into readily, moderately and sparingly available P. The P species were also determined by 31P NMR spectroscopy of 0.5M NaOH-0.1M EDTA extracts. Hedley et al.’s (1982) inorganic P extracted by anion exchange resin and by NaHCO3 are widely considered to be approximations to the actual plant available P. The availability to plants of other P fractions is less certain and this is examined in an experiment to compare the plant availability of various P fractions in soils from fertilized and unfertilized land uses following exhaustive cropping in the glasshouse. The soil texture for the sites studied included coarse sand, loamy sand, clayey sand, and sandy loam. Surface soils (0-10 cm) have pH(CaCl2) in the acidic range (mean 4.4) and there is no significant difference due to differences in land use (P<0.05). The soils are of low EC (1:5 H2O) - 6 mS m-1. There is an almost 5-fold variation in organic C among sites (from 1.4% to 8%) but organic C values did not show any significant effect (P<0.05) of changes in land use. To evaluate the degree of similarity of soils within each triplet set at a site principal component analysis was carried out on those soil chemical⁄mineralogical characteristics that were least likely to be affected by changes in land use practices. This analysis showed good matching of the triplet of sub-sites on the whole, especially for the duo of pasture and plantation land uses. This degree of matching of the trio of land uses was considered while interpreting the effects of land use on the forms and behaviour of soil P, and variations due to various extents of mismatch were mostly addressed using statistical techniques including regression analysis to interpret sub-site difference
12
Kitchen, Julie Louise. "Nutrition and nutrional value of wheat grown in organic and conventional farming systems in South Australia". Title page, table of contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09phk618.pdf.
Testo completo
13
Weggler-Beaton, Karin M. "The beneficial and detrimental effects of sewage sludge applications in South Australia". Title page, contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phw4113.pdf.
Testo completo
14
Crawford, Michael Cameron. "Quantification of the belowground inputs of organic carbon by the annual pasture legume barrel medic (Medicago truncatula Gaertn.)". Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phc8988.pdf.
Testo completoAbstract (sommario):
Bibliography: leaves 164-193. This study aims to quantify the belowground input of organic carbon by barrel medic using techniques that account for root death and decomposition as well as root secretion and exudation. It also investigates the effect of defoliation on carbon allocation within the plant so as to determine the potential for optimising carbon input to the soil through grazing management.
15
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.
Testo completo
16
Marsudi, Nada D. S. "Identification and characterization of root nodule bacteria from South-Western Australia soils able to nodulate Acacia saligna". Thesis, Marsudi, Nada D.S. (1997) Identification and characterization of root nodule bacteria from South-Western Australia soils able to nodulate Acacia saligna. Masters by Research thesis, Murdoch University, 1997. https://researchrepository.murdoch.edu.au/id/eprint/51836/.
Testo completoAbstract (sommario):
One hundred and thirty root nodule bacterial strains were isolated from nodules of Acacia saligna grown in ten different soils from nine locations in South- Western Australia. These isolates were confirmed as root nodule bacteria by reinoculation onto their host plant (A. saligna). Based on their morphological characteristics and growth rates on yeast mannitol agar (YMA), thirty nine strains were classified as fast-growing rhizobia and ninety four as slow-growing bradyrhizobia. The fast-growing strains were found in all soils except one from Narrikup which had the lowest pH (4.62).
Selected strains (20 fast-growing and 20 slow-growing) were characterized for their ability to grow:
•at acid pH (5 ± 0.2), or at alkaline pH (8.8 ±0.1)
•at 37°C
•on mannitol, fructose, arabinose, lactose or sucrose as sole carbon sources
•in the presence of 1 -3% (w/v) NaCl
The slow-growing bradyrhizobia were more acid-tolerant than the fastgrowing rhizobia, while the fast-growing rhizobia were more alkali tolerant than the slow-growing bradyrhizobia. Most fast-growing rhizobia grew at 37°C, whereas only two slow-growing bradyrhizobia could grow at this temperature. Both fast- and slowgrowing root nodule bacteria grew on mannitol, fructose and arabinose as a sole carbon source. All of the fast-growing rhizobia utilized the disaccharides (lactose and sucrose), whereas the slow-growing bradyrhizobia did not. All the slow-growing bradyrhizobia were sensitive to salt and did not grew even at 1% (w/v) NaCl. All of the fast-growing rhizobia grew at 1% NaCl and some at 3% NaCl.
In order to investigate the diversity within a segment of the 16S rRNA genes of these root nodule bacterial strains, 10 fast-growing rhizobial strains and 10 slowgrowing bradyrhizobia were selected, with Sinorhizobium meliloti WSM 419 as a control strain. A 260-264 bp segment of DNA from each strain (corresponding to positions 44 to 337 in the Escherichia coli 16 S rRNA gene) was amplified using the polymerase chain reaction (PCR) method and the amplified DNA sequenced. The 16S rRNA (DNA) sequences were then compared and aligned to those known for reference root nodule bacterial strains from the GenBank Data Library leading to a phylogenetic unrooted tree for the strains from A. saligna.
Analysis of the 16S rRNA gene sequences confirmed that the root nodule bacterial strains able to nodulate A. saligna can be separated into fast- and slow-growing strains.
The fast-growing rhizobia can be divided into two groups. The first group consists of six strains which showed 96.5-100% similarity over 260 bp to Rhizobium leguminosarum biovar phaseoli U29388. The second group consists of four strains which showed 97.7-100% similarity over 260 bp to Rhizobium tropici U38469. The slow-growing bradyrhizobia could also be grouped together. Six strains showed 97.3- 99.2% similarity over 264 bp to Bradyrhizobium japonicum Z35330. Three strains showed 99.2-100% similarity over 264 bp to Bradyrhizobium sp. (Lupinus) X87273 and strain YL68 showed 100% similarity over 262 bp to Bradyrhizobium sp. (Lupinus) U69636. S. meliloti WSM419 showed 100% similarity over 260 bp to Sinorhizobium sp. Z78204.
17
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.
Testo completoAbstract (sommario):
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.
18
Groves, Sarah Anne Biological Earth & Environmental Sciences Faculty of Science UNSW. "Spatial and temporal variation in the hydrochemistry of marine prawn aquaculture ponds built in acid sulfate soils, Queensland, Australia". Publisher:University of New South Wales. Biological, Earth & Environmental Sciences, 2008. http://handle.unsw.edu.au/1959.4/43273.
Testo completoAbstract (sommario):
Many brackish water aquaculture ventures in Australia and overseas have established ponds in coastal regions with acid sulfate soils (ASS). Acid sulphate soils are known to leach relatively high concentrations of metals, acid (metal and H+ ion) and sulfur, however very little is known about how these leached elements affect the water quality of aquaculture ponds. The main objective of this thesis was to describe the hydrochemical processes controlling the water chemistry in the water column and sediment pore water in the studied aquaculture ponds over time and space. Water samples providing the spatio-temporal data were collected from the ponds with the use of adapted sampling methods commonly used in the groundwater environment. A transect of five nested piesometers was installed in two prawn ponds at Pimpama, south east Queensland, Australia. Each piesometer nest contained a multilevel with eight outtakes, a mini ?? horizontal, and a slotted piesometer. Water samples were collected from each nested piesometer on a bi-monthly basis over the prawn-growing season. The unstable elements and water quality variables (pH, Eh, DO, EC, water temperature) were measured in the field. Stable elements were analysed in the laboratory using ICP-OES and ICP-MS. Soil samples were collected at the end of the season for elemental analysis. A number of key sediment/water interactions and processes such as precipitation/dissolution reactions, oxidation-reduction reactions, photosynthesis, adsorption and seawater buffering were identified as important controls on pond water conditions. This is the first study to provide detailed hydrochemcial analysis of the pond water over time and space and aided in identifying that even shallow water bodies can be chemically heterogeneous. Analysis of the water and sediment highlighted the selection of metals that can be associated with ASS and that are mobilised from pond sediments under certain chemical conditions. In Pond 7 Al, As, Ni and Zn concentrations were generally higher at the beginning of the grow-out season. Variability of the metal concentration was observed between the water column (0 ?? 1500 mm) and the pore-water (0 - -1000 mm). The highest concentration of Al (1044 ??g/L) and Zn (104 ??g/L) were sampled in the water column (approximately 400 mm from the surface of the pond). The highest concentration of As (130 ??g/L) and Ni (73 ??g/L) were sampled in the pore water sediment (associated with ASS). Elevated Mn and Fe2+ concentrations were also associated with the sediment pore water. The highest concentrations of Mn and Fe2+ were 4717 ??g/L and 5100 ??g/L respectively. In Pond 10, Ni concentrations (167 ??g/L) were the highest at the beginning of the grow-out season. However, As (97 ??g/L), Al (234 ??g/L) and Zn (308 ??g/L) were most concentrated during the middle of the cycle. The highest mean concentrations of these elements are As (63 ??g/L), Al (91 ??g/L) and Zn (69 ??g/L) which are each associated with the sediment-water interface. These metals are integral in degrading the pond water quality and lead to a loss of beneficial algal blooms, a reduction in pond water pH, poor growth rates and high mortality in shrimp. It is also possible that the dissolved ions and precipitated compounds that are leached from the ASS are discharged into the adjacent coastal estuary of Moreton Bay. With knowledge obtained from this PhD study, effective management and treatment systems can be developed and implemented to minimise the impact of these soils on the pond system and the water discharging into natural coastal ecosystem.
19
Nowicki, Thomas Edward. "The impact of plantations of Pinus spp. on the chemical properties of soils and stream waters in South African upland catchments". Doctoral thesis, University of Cape Town, 1998. http://hdl.handle.net/11427/17332.
Testo completoAbstract (sommario):
Bibliography: pages 171-181.Studies of forest ecosystems have indicated that internal sources constitute a significant component of the acid load to forest soils and can result in significant decreases in soil pH, acid neutralising capacity and base status. Despite this, the possibility that these processes can result in a significant transfer of acidity to drainage solutions and consequently to associated surface waters has, to a large extent, been discounted due to the self-limiting nature of " natural" acidification processes which purportedly do not involve significant concentrations of the strong acid anions NO₃⁻, SO₄²⁻ and Cl⁻. In South Africa, extensive plantations of Pinus spp. (pine) are developed in mountainous regions that were previously covered by grassland or fynbos (macchia) vegetation and are mostly not believed to be influenced by significant atmospheric pollution. Thus, a good opportunity exists to study the effects of afforestation without the superimposed influence of acid deposition. This thesis documents the results of a regional investigation of the geochemical impact of pine afforestation in South Africa. The study focuses specifically on factors relating to the transfer of soil acidity to drainage waters. The key questions that are addressed are : 1) to what extent is soil acidification, as previously documented for plantations in the eastern seaboard region of southern Africa, prevalent in other forestry areas within South Africa?; 2) in the absence of acid deposition, can afforestation cause enhanced concentrations of strong acid anions in soil solutions and drainage waters, and can this lead to the transfer of large quantities of acidity from forest soils to surface waters ?; 3) does afforestation-induced acidification lead to increased concentrations of environmentally important metals such as Al and Mn in soil solutions and surface waters ?; and 4) how does afforestation affect the quantity of dissolved organic matter in soils and streams?
20
Huang, Chunyuan. "Mechanisms of Mn efficiency in barley". 1996, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phh8739.pdf.
Testo completoAbstract (sommario):
Bibliography: leaves 131-153. This thesis investigates the mechanisms of manganese (Mn) efficiency (genetic tolerance to Mn-deficient soils) in barley (Hordeum vulgare L.) at both physiological and molecular levels.
21
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.
Testo completoAbstract (sommario):
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.
22
Thomas, Benjamin Mark. "The role of vesicular-arbuscular mycorrhizal fungi in Linum usitatissimum L. production in Southern Australian soils". Title page, contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09pht4541.pdf.
Testo completoAbstract (sommario):
Bibliography: leaves 106-132. This project investigated the role of VAM fungi in the growth and nutrition of Linum usitatissimum L. in agricultural soils in southern Australia. It had two general aims: (1) to examine the role of indigenous VAM fungi in the growth and nutrition of linseed in field soil collected near Clare, South Australia; and (2) to examine the effect of VAM fungi on the Zn nutrition of Linola.
23
Adolphson, Honi M. "Acari (Mite) Abundance And Diversity In Soil And Litter Layers Of Eucalyptus Globulus Labill (Tasmanian bluegum) Plantations In Southwest Western Australia". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2000. https://ro.ecu.edu.au/theses/1542.
Testo completoAbstract (sommario):
With the increased planting of E. globulus monoculture plantations, concerns surround the impact these mass plantings will have on the soil environment and wider ecosystem. Soil and litter mites are the dominant saprophages of terrestrial ecosystems, contributing to decomposition processes through their comminution and grazing activities. Despite the importance of mites to decomposition processes, there have been no investigations to date of the litter and soil communities under these plantations within Australia. This study investigated the impact of Eucalyptus globulus subsp. globulus (Tasmanian bluegum) monoculture plantations on the diversity and abundance of the soil and litter acarine (mite) fauna. Mite communities under three 8 year-old E. globulus plantations sited on reclaimed pastureland were compared with an adjacent native E. marginata (jarrah) forest and a grazed pasture in the mediterranean-type region of southwest Western Australia. Sites were sampled in spring 1997 and new sites randomly selected in autumn 1998. Large seasona1 variations in abundance and diversity were found between the sampling periods of spring 1997 and autumn 1998, influenced considerably by soil moisture. Species richness was consistently higher in both the soil and litter layers under native jarrah forest, with the E. globulus plantations intermediate in species richness between the native forest and grazed pasture. A total of 114 mite species/morphospecies was recognized; 16 Mesostigmata, 52 Prostigmata, 45 Oribatida (Cryptostigmata) and 1Astigmata. Species diversity in the surface litter was higher under the native forest, reflecting the greater heterogeneity of the litter. Diversity in the underlying soil was similar for the native forest and E. globulus plantation, although there were considerable differences in species richness. Soil diversity in the pasture was very poor in comparison to the two forest systems, reflecting the absence of a litter layer and reduced niche dimensions. The monospecific E. globulus litter possibly reduced niche variety by simplifying the physical habitat and reducing the variety of resources available for the saprophagous fauna, of which the oribatid mites are a major component. Consequently, the number of families represented in the microphytophagous, phytophagous and predator functional groups under the E. globulus plantation may have been reduced. The most common oribatid families under the plantation were those often reported from disturbed habitats, Oppiidae and Tectocepheidae, and those common in many habitats, Oppiinae and Oppiellinae. An important management implication arising from this study is that these plantations would harbour a more diverse mite fauna if planted as a mixed tree stratum.
24
McLaughlin, Michael John. "Phosphorus cycling in soil under wheat-pasture rotations /". Title page, contents and summary only, 1986. http://web4.library.adelaide.edu.au/theses/09PH/09phm1615.pdf.
Testo completo
25
Jenkins, Sommer. "Ecophysiological principles governing the zonation of puccinellia (Puccinellia ciliata) and tall wheatgrass (Thinopyrum ponticum) on saline waterlogged land in south-western Australia". University of Western Australia. School of Earth and Geographical Sciences, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0133.
Testo completoAbstract (sommario):
Puccinellia (puccinellia ciliata) and tall wheatgrass (Thinopyrum ponticum) often show ecological zonation in saline landscapes, with puccinellia occurring in less elevated more saline/waterlogged locations, and tall wheatgrass occurring in more elevated less saline/waterlogged locations. The aims of this study were to: (a) characterize the observed ecological zonation at a field site, (b) quantify the effects of variables likely to explain growth differences of the two plants in glasshouse experiments, and (c) identify and compare anatomical and physiological mechanisms that explain these zonation patterns. At an experiment in the field near Kojonup (0522824E, 6244579N), puccinellia was found to colonise the lower more severely salinised and waterlogged zones of the landscape, with tall wheatgrass occupying the higher less affected zones. These differences in zonation were clearly associated with variance in soil salinity and water-table depth. Glasshouse experiments in soil revealed that low pH values, low calcium concentrations and variation in salinity alone did not explain the ecological zonation observed in the field. However, there was a substantial difference in the responses of the two plant species to waterlogging in combination with salinity. Puccinellia grew better under saline waterlogged conditions than tall wheatgrass, which was associated with better regulation of Na+ and K+ under saline/waterlogged conditions than in tall wheatgrass. Under non-saline conditions, waterlogging (hypoxia) decreased shoot weights in puccinellia by 15% and in tall wheatgrass by 20%. Similar growth results were obtained in nutrient solution culture, where waterlogging was simulated by lowering the oxygen in solutions through bubbling with N2 gas. Under saline hypoxic conditions, puccinellia, compared to tall wheatgrass, showed increased growth and maintenance of selectivity of K+ over Na+ across adventitious roots. Solution experiments revealed adaptive traits responsible for conveying better growth and ion maintenance present in puccinellia, but not tall wheatgrass, such as inducement of a barrier to radial oxygen loss in the basal regions of adventitious roots (not previously reported in the literature for puccinellia), formation of root aerenchyma and packing of cortical cells and suberin deposition in hypodermal and endodermal root cell layers. These results should assist in targeting pasture species, and predicting their growth response, in saline and waterlogged landscapes. Further work on examining the genetic material of puccinellia is warranted in order to identify genes that could be transferred into crop plants to convey salt and waterlogging tolerance.
26
Naumann, Thomas E. "K-Ar Age Values of Bulk Soil Samples and Clay Fractions: Effects of Acid Extraction and Implications for the Origin of Micaceous Clay in Savannah River Site Soils, South Carolina, USA". Digital Archive @ GSU, 2010. http://digitalarchive.gsu.edu/geosciences_theses/27.
Testo completoAbstract (sommario):
Understanding how natural Cs, Rb, and K have been redistributed in Savannah River Site (SRS) soils during pedogenesis is important to understanding how radiocesium released to the soils will behave over the long term. In this effort, it is important to distinguish K that has participated in mineral-water reactions from that still residing in primary silicate structures, particularly in the clay fraction. The impact of different degrees of acid extraction on K and radiogenic Ar in bulk soil and in clay from five SRS soil samples has been determined. Strong treatment (50% HNO3, three hours, 100°C) releases K from primary minerals, as shown also by a concomitant release of radiogenic Ar, but a more moderate treatment (6% HNO3, three hours, 80°C) does not release K. K in the clay fraction is mostly nonexchangeable K in remnants of primary mica, and clay K-Ar age values near 300 Ma indicate the mica originated in the Appalachian mountain belt.
27
Farhoodi, Alireza. "Lime requirement in acidifying cropping soils in South Australia / by Alireza Farhoodi". Thesis, 2002. http://hdl.handle.net/2440/21842.
Testo completoAbstract (sommario):
"August 2002"Bibliography: leaves 230-254.
[11], 254 leaves : ill. (some col.), plates (some col.) ; 30 cm.
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.
Thesis (Ph.D.)--University of Adelaide, Dept. of Agronomy and Farming Systems, 2002
28
Reilly, Richard John. "Nitrate reduction in agricultural acid sulfate soil". Phd thesis, 2011. http://hdl.handle.net/1885/149927.
Testo completoAbstract (sommario):
A significant proportion of Australia's sugarcane crop is grown on east-coast estuarine floodplains underlain by pyritic gel-clay subsoils. At the current study site these agricultural acid sulfate soils are typically characterised by a topsoil horizon of river alluvium, a subsoil of oxidised actual acid sulfate soil (AASS), a zone of partially oxidised AASS and a deep sulfidic horizon of pyritic potential acid sulfate soil (PASS). Addition of nitrogenous fertiliser at key points in the sugarcane cropping cycle can create soil nitrogen levels in excess of immediate soil flora/fauna and crop requirements. In high rainfall tropical and sub-tropical regions conditions are thus suitable for nitrate, a strong oxidising agent, to leach down to the sulfidic soil layers with the consequent risk of pyrite oxidation. Little information is available on the fate of nitrogenous fertilisers in these pyritic subsoils. The purpose of this field and laboratory study was to evaluate the potential for nitrate reduction to occur in the presence of pyrite in sugarcane soils in the Tweed River valley, northern NSW, Australia. The study focus was on examining the soil profile hydrology including leaching mechanisms and nitrate concentrations down the profile to the AASS/PASS interface, as well as evaluating the potential for nitrate to increase the rate of pyrite oxidation in this generally anoxic soil zone.
Following an investigative nitrogen field trial to gather initial data, a second replicated urea fertiliser treatment trial with a nil-treatment control plot and three nitrogen (N) treatments was set up on a plant-cane-block in collaboration with a Tweed region cane grower, Robert Quirk. Installed loggers recorded rainfall, air and soil temperature, soil moisture and watertable data. Separate surveys and analytical work characterised selected soil physical, morphological and geochemical aspects. Soil profile sampling on four occasions over the twelve month crop cycle was analysed for N-species, NH{u2084}{u207A} and N0{u2083}{u207B}.
Hydraulic data analysis showed the watertable generally varying between 0.2 and 1.4 m below ground level with observed strong and rapid responses to rainfall events greater than approximately 15 mm per day. This and associated data supports the postulate that soil nitrate could move down the profile under even moderate precipitation events in these soils. Temperature, pH, redox potential and biological substrate soil data demonstrated the biogeochemical suitability of these subsoil zones to support nitrate reduction. Soil-N analysis revealed significant differences between N-trial treatments using urea fertiliser and also significant nitrogen transformation and movement within the soil profile.
Over a period of weeks, the urea fertiliser was rapidly transformed and appeared in the upper profile as elevated levels of ammonium and nitrate ions. The initial high ammonium levels quickly declined to be replaced almost completely by nitrate in the upper layers of the cane soil. Subsequently, increasing soil nitrate concentrations were evident deeper in the soil profile on higher nitrogen treatment plots during the middle phase of the crop cycle. In no instances were significant levels of nitrate detected below the soil redoxcline (the oxic-anoxic boundary) at around 1.0 m depth, nor was nitrate pooling evident anywhere in the AASS transition zone. Laboratory experimental work was undertaken to evaluate nitrate reduction coupled with pyrite oxidation under the biogeochemical conditions existing in the AASS transition zone. Results indicated that nitrate reduction associated with pyrite oxidation does take place in pyritic gel clay from the field site.
29
Heath, Lance. "An integrated approach to the remediation and management of coastal acid sulfate soils". Phd thesis, 2004. http://hdl.handle.net/1885/146393.
Testo completo
30
Kinsela, Andrew Stephen School of Biological Earth & Environmental Sciences UNSW. "Volatile sulfur compounds in coastal acid sulfate soils, northern N.S.W". 2007. http://handle.unsw.edu.au/1959.4/40889.
Testo completoAbstract (sommario):
The cycling of biogenic volatile sulfur compounds (VSCs) within marine and terrestrial ecosystems has been shown to play an integral role in atmospheric chemistry; by influencing global climate change through the creation of cloud condensation nuclei and controlling acid-base chemistry; as well as influencing sediment chemistry including the interactions with trace metals, particularly regarding iron sulfide formation. Despite this, the examination of VSCs within Australian coastal acid sulfate soils (ASS) is an unexplored area of research. As ASS in Australia occupy an area in excess of 9 M ha, there is a clear need for a greater understanding of the cycling of these compounds within such systems. This thesis looks at the concentrations of several VSCs within agricultural and undisturbed ASS on the east coast of Australia. Initial measurements of sulfur dioxide (SO2) were made using passive diffusion samplers, which were followed by two detailed field-based studies looking at the concentrations and fluxes of both SO2 and hydrogen sulfide (H2S) using flux-gradient micrometeorological techniques. These novel results indicated that this agricultural ASS was a substantial source of atmospheric H2S (0.036-0.056 gSm-2yr-1), and SO2 (0.095-0.31 gSm-2yr-1), with flux values equating to many other salt- and freshwater marshes and swamps. The flux data also suggested that the ASS could be a continual source of H2S which is photo-oxidised during the daytime to SO2. Measurements of both compounds showed separate, inverse correlations to temperature and moisture meteorological parameters indicating possible contributing and / or causal release factors. Further identification of these and other VSCs within ASS samplers was undertaken in the laboratory using gas chromatography in combination with solid-phase microextraction. Although SO2 and H2S were not discovered within the headspace samples, two other VSCs important in atmospheric sulfur cycling and trace metal geochemistry were quantified; dimethylsulfide (DMS; > 300??g/L) and ethanethiol (ESH > 4??g/L). The measurements of H2S, DMS and ESH are the first quantifications with Australian ASS, and they may be important for refining regional or local atmospheric sulfur budgets, as well as interpreting previous SO2 emissions from ASS. Ultimately this thesis further enhances our understanding of the cycling of VSCs within acid sulfate systems.
31
Wallace, Luke Joshua. "Sulfur storage and dynamics in an inland acid sulfate soil system of the lower Murray River floodlplains of South Australia". Phd thesis, 2009. http://hdl.handle.net/1885/148378.
Testo completo
32
Currie, Dougal Robert. "Soil physical degradation due to drip irrigation in vineyards: evidence and implications". Thesis, 2007. http://hdl.handle.net/2440/58642.
Testo completoAbstract (sommario):
Drip irrigation is the most common method of water application used in Australian vineyards. However it places physical and chemical stress upon soil structure, which may affect soil physical properties, soil water availability and grapevine functioning. Common soil types within Australian vineyards appear vulnerable to soil degradation and there is emerging evidence of such degradation occurring. Two South Australian vineyards (one located at Nuriootpa in the Barossa Valley, the other in the McLaren Vale winegrowing region) were used to examine evidence of altered soil physical properties due to irrigation. Significantly higher soil strength and lower permeability was found under or near the dripper in irrigated soils. There was also evidence that irrigation increased subsoil bulk density at Nuriootpa. It was uncertain how irrigation caused these changes. While sodicity was present at Nuriootpa, it appeared the physical pressures exerted by irrigation, such as rapid wetting and prolonged wetness, also contributed. To gauge the severity of the degradation at Nuriootpa, a modelling study assessed the impact of higher soil strength and salinity on grapevine transpiration. The SWAP model (Soil- Water-Atmosphere-Plant) was modified and then calibrated using soil moisture data from Nuriootpa. Simulations were conducted for different irrigation regimes and the model output indicated that degradation led to a reduction in cumulative transpiration, which was almost entirely due to higher soil strength. However the reduction was relatively minor and there was evidence of water extraction by roots in all soil layers. Hence the degradation, in terms of higher soil strength and salinity, was not considered a significant management problem in the short - term. Evidence of increased waterlogging and its consequences require further investigation. Roots were observed in soils at Nuriootpa with penetration resistance (PR) much greater than 2 MPa, which was thought to completely impede grapevine root growth. It was hypothesised that roots avoided the physically hostile matrix by using biopores or structural cracks. A pot experiment tested this hypothesis and examined the relationship between soil strength, biopores and root growth for grapevines. Grapevine rootlings (cv. Cabernet Sauvignon) were grown into pots with varying degrees of soil compaction, with and without artificial biopores. No root growth occurred when PR>2 MPa unless biopores were present. Pores also improved root growth in non-compacted soil when PR approached 1 MPa, which suggested biopores influence root growth in soils regardless of compaction levels. Therefore PR should not be the only tool used to examine the rooting-potential of a vineyard soil. An assessment of soil structure, such as biopore density and size, should be incorporated. In drip-irrigated vineyards, there is a possibility that degraded clayey subsoils could be ameliorated by manipulating zones of soil drying. At distances away from the dripper, drying events could generate shrinkage cracks that improve drainage and provide opportunities for root growth. From a practical perspective, drying events could be manipulated by moving the dripper laterally or by changing the irrigation frequency and intensity. The potential of this simple, non-invasive, ameliorative approach was investigated. Large, intact cores were sampled from Nuriootpa subsoil where degradation had been identified. Individual core bulk density was calculated using a formula that was derived by solving two common soil physics equations simultaneously. This proved to be an accurate and non - invasive method. Half the cores were leached with a calcium solution, and the saturated hydraulic conductivity (K [subscript s] ) was measured on all cores before and after drying to a matric potential of -1500 kPa. Soil drying led to a significant increase in K [subscript s], which indicated an improvement in structure through the creation of shrinkage cracks and heaving. Calcium treatment had no impact on K [subscript s], but that could change with more wetting and drying cycles. Results indicated the need for further investigation in the field, where different compressive and tensile forces operate. Harnessing this mechanism may provide an attractive soil management option for growers. The soil physical degradation identified is concerning for sustainable production in irrigated vineyards. Given the sites were representative of typical irrigation practices, such degradation may be widespread. While modelling suggested the impact of higher soil strength and salinity was minimal, these properties should be monitored because they may worsen with continuing irrigation. Furthermore, the impact of irrigation on subsoil permeability needs to be defined more accurately. An increased incidence of waterlogging could significantly restrict production, which was evident when overly wet growing seasons were modelled. If subsoil permeability was found to be significantly lower in irrigated soils, amelioration may be required. In this instance, the use of drying events to generate structure provides an option. Ultimately, the impact of drip irrigation on soil physical quality warrants further attention, and it is imperative to monitor the physical quality of vineyard soils to ensure sustainable production.Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007.
33
Harris, Mark Anglin. "The effects of green manure on soil structure in calcareous sodic and non-sodic soils". 1996. http://web4.library.adelaide.edu.au/theses/09A/09ah315.pdf.
Testo completo
34
Chen, Juan. "Mobility and environmental fate of norflurazon and haloxyfop-R methyl ester in six viticultural soils of South Australia / by Juan Chen". Thesis, 1999. http://hdl.handle.net/2440/22415.
Testo completoAbstract (sommario):
Bibliography: leaves 67-72.ix, 72 leaves : ill. ; 30 cm.
The main objective of this research project was to study the environmental fate and mobility of two herbicides registered for use in Australian viticulture, namely norflurazon and haloxyfop-R methyl ester.
Thesis (M.App. Sc.)--University of Adelaide, Dept. of Environmental Science and Management, 2000
35
Thomas, Mark. "Multiscale prediction of saline-sodic land degradation processes in two South Australian regions". 2007. http://hdl.handle.net/2440/57337.
Testo completoAbstract (sommario):
Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library.In this thesis, the distribution of saline-sodic properties forming part of a complex pattern of soils in two varied upland agricultural regions in South Asutralia were predicted at multiple scales using DSM and allied approaches.
http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1283986
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007
36
Thomas, Mark. "Multiscale prediction of saline-sodic land degradation processes in two South Australian regions". Thesis, 2007. http://hdl.handle.net/2440/57337.
Testo completoAbstract (sommario):
In this thesis, the distribution of saline-sodic properties forming part of a complex pattern of soils in two varied upland agricultural regions in South Asutralia were predicted at multiple scales using DSM and allied approaches.Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007
37
Fotovat, A. "Chemistry of indigenous Zn and Cu in the soil-water system : alkaline sodic and acidic soils / by Amir Fotovat". 1997. http://hdl.handle.net/2440/19068.
Testo completoAbstract (sommario):
Copies of author's previously published articles inserted.Bibliography: leaves 195-230.
xx, 320 leaves : ill. (some col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
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.
Thesis (Ph.D.)--University of Adelaide, Dept. of Soil Science, 1998
38
Clough, Angela. "Nitrogen and carbon mineralisation in agricultural soils of South Australia / by Angela Clough". 2001. http://hdl.handle.net/2440/22426.
Testo completoAbstract (sommario):
"September 2001"Bibliography: leaves 144-159.
xix, 159 leaves : ill. ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
The two main aims of this study were: 1) to determine if the presence of Calcium carbonate in soil was the reason behind soils from Yorke Peninsula having relatively high OC (organic carbon) contents, given local farming practices, and 2) to determine the effect that the composition of the soils' OC has on the mineralisation rates.
Thesis (Ph.D.)--University of Adelaide, Dept. of Agronomy and Farming Systems, 2002
39
D{u00FC}rr, Mira. "Biogeochemistry of acid sulfate soils : an investigation of the molecular characteristics of the bacterial and archaeal community". Phd thesis, 2008. http://hdl.handle.net/1885/150961.
Testo completo
40
Reith, Frank. "The geomicrobiology of gold : interaction of bacteria with gold in Australian soils and deeper regolith materials". Phd thesis, 2005. http://hdl.handle.net/1885/148516.
Testo completo
41
Smith, Michael Shane. "The geochemistry of alkaline salt-affected soils". Phd thesis, 2009. http://hdl.handle.net/1885/151491.
Testo completo
42
Lotfollahi, M. "The effect of subsoil mineral nitrogen on grain protein concentration of wheat / by Mohammad Lotfollahi". 1996. http://hdl.handle.net/2440/18896.
Testo completoAbstract (sommario):
Copy of author's previously published work inserted.Bibliography: leaves 147-189.
xxi, 189 leaves : ill. (some col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
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.
Thesis (Ph.D.)--University of Adelaide, Dept. of Soil Science, 1997
43
Manson, Alan David. "Sodium, cation exchange and crop response in acid KwaZulu-Natal soils". 2000. http://hdl.handle.net/10413/4951.
Testo completoAbstract (sommario):
In many acid, highly leached South African soils, Na levels are very low. Applications of Na to
highly leached soils may be advantageous in some situations as Na has been shown to interact
with soil acidity, P availability, and K nutrition of plants.
It was found that an increased level of Na at constant anion concentration in the soil solution
resulted in lower soil solution pH and Al3
+ activity, and improved maize root penetration into an
acid subsoil (pot trial). In another pot trial, Na did not improve lucerne root growth into the same
subsoil.
In a field trial on a limed, low-Na soil with severe subsoil acidity, the effects off our rates of Na,
three Na carriers, and three rates of gypsum on maize growth were compared. In three out of
four seasons grain yield responses to the Na applications were positive, and of a similar magnitude
to the response to gypsum (455-925 kg ha). In another field trial with maize, responses to Na
(of up to 1027 kg grain ha) were recorded in two out of three years on plots with topsoil acid
saturations of greater than 45%. The reason for the responses to Na was probably improved
subsoil rooting as a result of modified soil solution composition in the presence of Na.
In a field trial with Italian rye grass on an acid, highly weathered soil, the effect of sodium
applications were investigated at different levels of lime and K. In the first season, 200 kg ha
Na as NaCl increased dry matter yield from 11289 kg ha to 12815 kg ha , Sodium responses
were possibly due to enhanced P uptake, or Na substitution for K, or a combination of the two
mechanisms. No consistent lime x Na interaction was observed. Potassium and Na applications affected the mineral balance of the herbage produced. Potassium depressed herbage Ca, Mg and
Na concentrations, and Na depressed herbage Ca and Mg where herbage K was low, but had no
effect on herbage K. Where soil P and K reserves are marginal, rye grass pastures may benefit
from Na applications.Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2000.
44
Bagheri, Kazemabad Abdolreza. "Boron tolerance in grain legumes with particular reference to the genetics of boron tolerance in peas / Abdolreza Bagheri Kazemabad". Thesis, 1994. http://hdl.handle.net/2440/21513.
Testo completo
45
Nathan, Muhammad. "Clay movement in a saline-sodic soil toposequence". Thesis, 2001. http://hdl.handle.net/2440/109032.
Testo completoAbstract (sommario):
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.Thesis (M.Ag.Sc.) -- University of Adelaide, Dept. of Soil and Water, 2002
46
Gillen, John (Jake) Spencer. "An ecological study of the landscape, perennial plants and soils of the cooper creek floodplain, South Australia". Phd thesis, 2010. http://hdl.handle.net/1885/111996.
Testo completoAbstract (sommario):
This study presents a quantitative account of vegetation-soil
relationships for the perennial vegetation of the Cooper Creek
floodplain, in South Australia. Cooper Creek is an
internationally significant and increasingly rare example of one
of a naturally functioning, unregulated, dryland river system
both nationally and internationally. The area for this study is
delineated by the boundaries of the Ramsar listed Coongie Lakes
wetland complex. This is a region of unique ecological
significance: a highly biologically productive floodplain system
within the extensive dune fields of the Strzelecki Desert.
The current parlous environmental state of the rivers of the
Murray Darling Basin reinforces the significance of Cooper Creek
as a valuable reference system. Increased understanding of the
functioning of this system provides valuable insights into future
rehabilitation and restoration programs for degraded
dysfunctional river systems elsewhere in Australia. The
development of an ecological ‘knowledge framework’ for
Australian dryland rivers is a still evolving process. This study
has contributed to the development of this ecological knowledge
framework through the study of the soils and vegetation examined
at 138 sites in the region. A combination of indirect and direct
gradient analyses in conjunction with generalised linear mixed
modelling has revealed the main, statistically significant,
edaphic factors influencing the distribution and abundance of a
range of floodplain perennial plant species of the lower reaches
of the Cooper Creek. These main edaphic factors influencing the
range of species examined include: pH, salinity, texture, total
organic carbon, cation exchange capacity, potassium and calcium
carbonate.
Detailed available information on the nature of the predominantly
fine textured soils of the Cooper Creek floodplain is scarce.
These soils represent the Vertosol group of the range of soil
orders belonging to the Australian Soil Classification. This
study presents the results of a detailed multidisciplinary
investigation into the origin and properties of these soils
The numerical classification of soil data has provided insight
into the range of soil types on the floodplain and their
associated physical and chemical characteristics. In addition to
orthodox analytical methods the soils from the surface 10 cm at
all sites were also analysed using mid infrared (MIR) spectral
analysis. There is a dearth of MIR data for the floodplain soils
of Australian dryland river systems.
Formal analyses and personal observation have combined to provide
insight into the potential significance of Eucalyptus coolabah as
a key ecosystem species influencing the structure and functioning
of floodplain ecology. Examination of Eucalyptus coolabah
distribution has also provided insight into potentially
significant groundwater recharge zones within the floodplain.
47
Adcock, Damien Paul. "Soil water and nitrogen dynamics of farming systems on the upper Eyre Peninsula, South Australia". Thesis, 2005. http://hdl.handle.net/2440/37810.
Testo completoAbstract (sommario):
In the semi - arid Mediterranean - type environments of southern Australia, soil
and water resources largely determine crop productivity and ultimately the sustainability of farming systems within the region. The development of sustainable farming systems is a constantly evolving process, of which cropping
sequences ( rotations ) are an essential component. This thesis focused on two important soil resources, soil water and nitrogen, and studied the effects of different crop sequences on the dynamic of these resources within current farming systems practiced on the upper Eyre Peninsula of South Australia.
The hypothesis tested was that : continuous cropping may alter N dynamics but will not necessarily alter water use efficiency in semi - arid Mediterranean - type environments. Continuous cropping altered N - dynamics ; increases in inorganic N were dependent on the inclusion of a legume in the cropping sequence.
Associated with the increase in inorganic N supply was a decrease in WUE by the subsequent wheat crop. Overall, estimates of water use efficiency, a common index of the sustainability of farming systems, in this study concur with reported values for the semi - arid Murray - Mallee region of southern Australia and other
semi - arid environments worldwide.
Soil water balance and determination of WUE for a series of crop sequences in this thesis suggests that the adoption of continuous cropping may increase WUE and confer a yield benefit compared to crop sequences including a legume component in this environment. No differences in total water use ( ET ) at anthesis or maturity were measured for wheat regardless of the previous crop. Soil evaporation ( E [subscript s] ) was significantly affected by crop canopy development, measured as LAI from tillering until anthesis in 2002, however total seasonal E [subscript s] did not differ between crop sequences. Indeed in environments with infrequent
rainfall, such as the upper Eyre Peninsula, soil evaporation may be water - limited rather than energy limited and the potential benefits from greater LAI and reduced E [subscript s] are less.
Greater shoot dry matter production and LAI due to an enhanced inorganic N supply for wheat after legumes, and to a lesser degree wheat after canola, relative to continuous cereal crop sequences resulted in increases in WUE calculated at anthesis, as reported by others. Nonetheless the increase in WUE was not sustained due to limitations on available soil water capacity caused by soil physical and chemical constraints. Access to more soil water at depth ( > 0.8m ) through additional root growth was unavailable due to soil chemical limitations. More importantly, the amount of plant available water within the ' effective rooting depth ' ( 0 - 0.8m ) was significantly reduced when soil physical factors were accounted for using the integral water capacity ( IWC ) concept. The difference between the magnitude of the plant available water capacity and the integral water capacity was approximately 90mm within the ' effective rooting depth ' when measured at field capacity, suggesting that the ability of the soil to store water and buffer against periodic water deficit was severely limited. The IWC concept offers a method of evaluating the physical quality of soils and the limitations that these physical properties, viz. aeration, soil strength and hydraulic conductivity, impose on the water supply capacity of the soil.
The inability of the soil to maintain a constant supply of water to satisfy maximal transpiration efficiency combined with large amounts of N resulted in ' haying off ', and reduced grain yields. A strong negative linear relationship was established between WUE of grain production by wheat and increasing soil NO₃ - N at sowing in 2000 and 2002, which conflicts with results from experiments in
semi - arid Mediterranean climates in other regions of the world where applications of N increased water use efficiency of grain.
Estimates of proportional dependence on N₂ fixation ( % N [subscript dfa] ) for annual medics and vetch from this study ( 43 - 80 % ) are comparable to others for environments in southern Australia ( < 450mm average annual rainfall ). Such
estimates of fixation are considered low ( < 65 % ) to adequate ( 65 - 80 % ). Nevertheless, the amount of plant available N present at sowing for subsequent
wheat crops, and the occurrence of ' haying off ', suggests that WUE is not N - limited
per se, as implied by some reports, but constrained by the capacity of a soil to balance the co - limiting factors of water and nitrogen.Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2005.
48
O'Hara, Christopher. "The significance of soil physical fractions for the cycling of phosphorus, carbon and nitrogen in forests of south-east Australia". Phd thesis, 2003. http://hdl.handle.net/1885/148509.
Testo completo
49
Thomas, Benjamin Mark. "The role of vesicular-arbuscular mycorrhizal fungi in Linum usitatissimum L. production in Southern Australian soils / Benjamin Mark Thomas". Thesis, 2001. http://hdl.handle.net/2440/19876.
Testo completoAbstract (sommario):
Bibliography: leaves 106-132.iv, 132 leaves : ill. ; 30 cm.
This project investigated the role of VAM fungi in the growth and nutrition of Linum usitatissimum L. in agricultural soils in southern Australia. It had two general aims: (1) to examine the role of indigenous VAM fungi in the growth and nutrition of linseed in field soil collected near Clare, South Australia; and (2) to examine the effect of VAM fungi on the Zn nutrition of Linola.
Thesis (Ph.D.)--University of Adelaide, Dept. of Soil and Water, 2001
50
Cooper, David Seth. "Genetics and agronomy of transient salinity in Triticum durum and T. aestivum". 2005. http://hdl.handle.net/2440/59204.
Testo completoAbstract (sommario):
Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library.Transient salinity in soils is characterised by high concentrations of salts in the subsoil. Durum wheat (Triticum turgidum L. Var. durum) is less tolerant of transient salinity than locally developed bread wheat (Triticum aestivum) varieties, and this results in reliable durum production being restricted to relatively unaffected soils. Field trials were conducted to assess the relative impact of transient salinity, boron toxicity and bicarbonate on crop production and highlighted the importance of combining tolerance to all three subsoil constraints into varieties intended for widespread adoption; and if the area of durum production is to be expanded. The Na exclusion locus from the landrace Na49 was found to improve the adaptation of durum to sites affected by transient salinity and is now being intogressed into a wide range of breeding material.
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Thesis (Ph.D.) -- University of Adelaide, School of Agriculture and Wine, 2005