Management of Structurally Degraded Soils
Soil Chemistry and Fertility
Land Application of waste
Rehabilitation of Mined Lands
Plant Nutrition
Miscellaneous
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Research Activity
To view current and recent projects conducted within Soils and Land Resources, scroll down the page. Projects have been grouped under six headings.
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A. Management of Structurally Degraded Soils
Comparative studies of the water use characteristics of native tree species
A/P Bing So and Dr David Mulligan (CMLR, UQ)
Reclamation of highly disturbed lands includes restoring a diverse stable plant community. Protocols to accomplish this must be developed including strategies that acknowledge the many environmental constraints that may affect tree growth and survival. Interactions in re-constructed ecosystems can be classified into above-ground and below-ground processes; it is evident that much more is known about the former than the latter. A critical issue relating to sustainability is the influence that trees are likely to have on the water table and moisture status throughout the soil profile, and the converse, i.e. the effect of water or lack of it on the trees.
This study is concerned with the relationships between tree productivity and its water relations and the root characteristics. While the general objective of the study was to develop a better understanding of the soil-plant water interactions of native Australian tree species (Eucalyptus and Acacia spp.), the specific objectives were (1) to study the comparative water use characteristics of a range of native tree species used in the rehabilitation of disturbed lands, and in particular their root characteristics in the glasshouse, and (2) to study the water relations of trees in a mixed community in the field. An experimental system was set up and used to monitor the water balance of individual trees.
Collaborators:
Mr Wilfredo Sanidad*, School of Land and Food Sciences, UQ
Dr Kamal Yatapanage, School of Land and Food Sciences, UQ
Mr Peter Horn, School of Land and Food Sciences, UQ
Mr Nick Currey, Kidston Gold Mines Ltd
Mr Paul Ritchie, Kidston Gold Mines Ltd
Duration of Project: 1997-2002
Funding Agencies:
AusAID
Kidston Gold Mines Ltd
Subsoil sodicity and its potential effect on soil productivity
A/P Bing So and Dr Ram Dalal (QDNRM, Indooroopilly)
Surveys of crop yields over the last 30 years on the marginal cropping areas of NSW and Queensland have shown only small gains in yield despite improvement of wheat and barley cultivars. In these areas, low rainfall and high sodium levels in predominantly heavy clay soils lead to low water storage capacity and high salinity levels, thus limiting water extraction and use by crops and crop yields.
This project has assessed and quantified the effects of subsoil constraints such as sodium and salinity levels on crop yields and crop water use in these regions. The project has provided data for modelling and the derivation of guidelines for property management planning that will enable farmers to identify areas capable of being sustainably and profitably cropped.
Collaborator:
Ms Mirella Blasi*, School of Land and Food Sciences, UQ
Duration of Project: 1998-2002
Funding Agency:
GRDC
The influence of organic matter on soil structural stability and CO2 release during cultivation
A/P Bing So
Soil structure is an important determinant of soil quality. It is made up of soil particles grouped together and bonded physically or chemically by different agents through several mechanisms, which will determine the stability of the aggregates and their resistance to energy input and microbial attack. An important binding agent that can be readily managed is organic matter.
The overall aim is to determine the role of SOM in the development and maintenance of soil structure, and conversely the role of soil structure in the protection and breakdown of SOM. The specific objectives are (1) to identify the OM types responsible for bonding soil aggregates, (2) the susceptibility of the SOM to degradation and (3) to investigate the factors (OM, tillage, water content, temperature) affecting CO2 release from the soil.
Organic Carbon (Heanes) and total-C (LECO) content of the soil separates tend to increase with decreasing aggregate size from >20-2000 to <2mm. For aggregates >20mm, the OC content tends to decrease with increasing applied energy (from 0.04 to 0.20 J/g soil/min). Results from XPS surface analysis, to determine the type of SOM, are not conclusive and require further work. Degradation of OC from soil fractions is still being conducted.
Collaborators:
Yulnafatmawita*, School of Land and Food Sciences, UQ
A/P Neal Menzies, School of Land and Food Sciences, UQ
Dr Ram Dalal, QDNRM, Indooroopilly
Duration of Project: 1999-2002
Funding Agencies:
AusAID
CRC for Greenhouse Accounting
The change in soil physical properties produced by controlled and reduced tillage in sugarcane soils and the effect of soil densification on nitrogen availability
Dr Usha Pillai-McGarry (School of Agriculture and Horticulture, UQ)
The high risk of soil degradation in sugarcane soils during land preparation can be attributed to the large number of vehicular passes made in wet/moist soil. Soil degradation results in reduced productivity and off-site pollution due to erosion losses. This project has assessed the necessity for conventional cultivation of the whole paddock prior to planting cane. In the paddock, changes in soil physical condition in rows and inter-rows was measured under alternative management practices such as strategic/minimum tillage and controlled traffic. The interaction of soil physical measurements with soil structure obtained through image analysis was related to nitrogen availability for plant growth. In the laboratory, the effect of bulk density on the hydraulic properties of two cane soils and its consequent effects on denitrification were studied.
Collaborators:
Dr M. Habibur Rahman*, School of Land and Food Sciences and School of Agriculture and Horticulture, UQ
Dr Des McGarry, QDNRM, Indooroopilly
Dr M. Braunack, BSES, Tully
Mr N. Halpin, QDNR, Bundaberg
Duration of Project: 1996-2001
Funding Agency:
Sugar Industry Reference Panel (SIRP)
B. Soil Chemistry and Fertility
Management of phosphorus for sustainable food crop production on acid upland soils in Australia, Philippines and Vietnam
A/P Pax Blamey, A/P Neal Menzies, A/P David Edwards, Mr Graham Kerven and A/P Rob Cramb (School of NRSM)
The two billion hectares of tropical and subtropical acid upland soils represent an important area of arable land that can be prudently cultivated. Such soils are widespread throughout Southeast Asia, and in tropical and subtropical eastern Australia. These soils rapidly lose their fertility through cropping, especially where nutrients lost through the removal of harvested products and through leaching and runoff are not replaced. Along with Al toxicity, P deficiency is arguably the most widespread limitation to sustainable food crop production on acid upland soils. These soils generally have initial low levels of plant-available P and there is often high fixation of applied P. Improved efficiency of P utilisation would therefore be of major economic benefit. One solution to this problem is to reduce the rate of chemical transformation of P into plant-unavailable forms. In this project, P fertilisers, organic manures, green manure crops and lime will be used to manipulate the rate of transformation of P between the various pools in the soil. The aim is to improve the ability of plant roots to compete for P against chemical fixation processes. The primary objective of the project is to identify, and where possible develop, economic, sustainable and farmer-acceptable technologies for improved production of groundnut, maize and soybean on upland acid soils by the more efficient utilisation of applied P. A secondary objective is to understand and model the dynamics of P in acid upland soils. A review of this project resulted in it being extended for 2 years to allow the demonstration of promising technologies to farmers.
Collaborators:
Prof. Conrado Duque, Central Mindanao Univ., Philippines
Dr Pect Evangelista, Bureau of Soil and Water Management, Philippines
Assoc. Prof. Thai Phien, National Institute for Soils and Fertilizers, Vietnam
Dr Rod Lefroy, IBSRAM, Bangkok, Thailand
Duration of Project: 1996-2002
Funding Agency:
ACIAR
Conservation farming and long-term changes in soil organic matter status and their impact on soil acidification
A/P David Edwards and Prof Clive Bell
Land degradation through soil acidification is adversely affecting some 5 x 106 hectares of agriculturally productive land in northeastern Victoria. Lost productivity of these soils has been attributed to toxic levels of A1 which have developed under the conservation farming practices that have been shown to reduce soil erosion. Field studies on Kurosols and Dermosols have determined overall acidification rates for the 0-20 cm soil zone and shown that they increase in the order stubble incorporated > stubble standing > stubble shredded > stubble burnt. Long-term monocultures of continuous lupin and continuous wheat, although not recommended practice, were studied to illustrate the changes in soil chemical characteristics throughout the profile that occur as a result of long-term soil acidification. Acidification was mainly attributed to nitrate leaching with organic C loss over 15 years acting as a sink for protons produced from hydrolysis reactions. For every 1% loss in organic C, the loss in soil buffering capacity was calculated to be 3.9 cmol (+) kg-1. The complexation of A1 in soil solutions was also examined in these soils, and the role of low molecular weight organic acids, humic acid and fulvic acid in reducing A1 toxicity determined.
Collaborator:
Dr Bill Slattery*, Rutherglen Research Institute, Agriculture Victoria, Rutherglen
Duration of Project: 1992-2001
Funding Agency:
Agriculture Victoria
Dynamics of amelioration of aluminium toxicity and base deficiency by organic materials in highly weathered acid soils
Prof. Clive Bell and A/P David Edwards
The development of sustainable farming systems in the humid and sub-humid tropics demands the replacement of plant nutrients depleted during crop production and the correction of acid soil infertility. Although the capacity of organic materials to alleviate acid soil infertility has long been recognised, little is known of their role in ameliorating A1 toxicity and cation deficiency. The objectives of the study were to determine the mechanisms by which organic materials ameliorate A1 toxicity and Ca deficiency and to identify chemical characteristics of organic materials that may make them useful in overcoming these limitations to plant growth. Short-term root elongation studies of mungbean were conducted in an A1-toxic surface soil and a Ca-deficient subsoil amended with a wide range of organic materials. Limitations to root growth were identified by extracting soil solution from the amended soils and comparing the monomeric A1 activity and the Ca activity ratio with published critical values for mungbean. It was shown that organic materials that ameliorate A1 toxicity do so by increasing soil solution pH, while organic materials with a ratio of Ca to other cations <0.3 induced or maintained Ca deficiency.
Collaborator:
Mr Peter Larsen*, School of Land and Food Sciences, UQ (now Greenfield Resource Options, Milton, Qld)
Duration of Project: 1992-2002
Funding Agency:
ACIAR
Nutrient management strategies for dryland farming systems on chemically degraded Ferrosols
A/P Neal Menzies
The declining productivity of the continuously cropped Ferrosols of the South and Central Burnett has been attributed to changes in soil physical and chemical properties. Issues of particular concern are decreased soil organic matter, increased subsoil acidification, general nutrient depletion (especially of potassium and zinc) and a stratification of remaining nutrient reserves. Responses to surface application of potassium and lime, in particular, have been limited due to the physical isolation of the applied amendments in dry surface layers. An increased awareness of these limitations by resource users has prompted a re-evaluation of the effectiveness of reduced tillage systems versus deep ploughing for achieving higher crop yields, at least in the short term. A trend back to aggressive, soil inversion practices is considered to be highly undesirable because of the risk of reduced rainfall infiltration and the associated increase in soil erosion.
This project has focussed on development of an understanding of the relationship between management practices and soil chemical characteristics, with the intent of developing farming systems capable of preventing further physical and chemical degradation of soils whilst maintaining or improving productivity and farm viability.
Collaborators:
Ms Jonnie White*, School of Land and Food Sciences, UQ
Dr Mike Bell, QDPI, Kingaroy
Dr Brian Bridge, CSIRO (at Leslie Research Centre, Toowoomba)
Duration of Project: 1996-2002
Funding Agencies:
LWRRDC
QDPI
Chemistry, analysis and environmental impacts of acid sulfate soils
A/P Neal Menzies
Oxidation of pyrite containing soils, either naturally or facilitated by human intervention, can produce sulfuric acid as a by-product. These so-called acid sulfate soils, by virtue of their low pH (often <4.0), solubilise large quantities of iron and aluminium which then drains into waterways, adversely impacting on aquatic biota. Such pyritic soils exist in many coastal areas of eastern Australia, but their distribution and abundance are poorly understood.
Identification, risk mapping and management of these soils is dependent upon their chemical analysis. At present, opinion is strongly divided over what methods should be employed to identify acid sulfate soils. Work in progress aims to determine the relationships between the results obtained by various analytical approaches, with a view to developing better and more widely applicable methods for characterising acid sulfate soils. The research also aims to develop a detailed understanding of the chemistry of acid sulfate soils, the water draining from them and the interaction of the resulting “contaminants” with natural water bodies. In particular, the role of aluminium and the oxidation products of pyrite are of interest.
Collaborators:
Mr Angus McElnea*, QDNRM, Indooroopilly
Dr Ian Willett, ACIAR, Canberra
Mr Col Ahern, QDNRM, Indooroopilly
Mr Dennis Baker, Ryan and Associates, Sunnybank Hills
Duration of Project: 1996-2002
Funding Agencies:
NLP
QDNRM
Dynamics of nitrogen and phosphorus release from land applied piggery sludge
A/P Neal Menzies
Piggery sludge contains high concentrations of nutrients (N, P and K) which have the potential to cause environmental harm if sludge is applied to crops and pastures in excess of the plants’ capacity to capture nutrients. However, the sludge is a valuable resource if used in an appropriate manner. Land disposal of piggery effluent and sludge has been identified as the most critical environmental issue facing the industry and the environmental regulations need to be scientifically justified. In order to manage the land application of piggery sludge, a better understanding of the dynamics of N and P release following application is required. Field and laboratory studies have provided quantitative data on processes such as rates of mineralisation of organic N, the role of soil organic N, and volatilisation and denitrification rates.
Collaborators:
Ms Yoland Kliese*, School of Land and Food Sciences, UQ
Dr Ram Dalal, QDNRM, Indooroopilly
Dr Wayne Strong, Leslie Research Centre, Toowoomba
Duration of Project: 1997-2002
Funding Agencies:
PRDC
UQ (PhD Completion Scholarship)
Influence of organic matter on phosphorus phytoavailability
A/P Neal Menzies and A/P Pax Blamey
The highly weathered soils of the humid tropics strongly absorb phosphate, rendering it unavailable for plant uptake. Thus, the efficiency of phosphorus fertilisers in these soils is generally low. In native vegetation systems on these soils, phosphorus principally cycles through organic forms. The present research aims to determine the role of organic matter in supplying phosphorus to arable crops grown on these soils. The study has focussed on: (i) the effects of organic matter on phosphorus reaction with the inorganic solid phase, and (ii) the partitioning of phosphorus between organic and inorganic forms. The research has endeavoured both to provide an understanding of the chemistry of phosphorus-organic matter interactions, and to evaluate the role of organic matter in supplying phosphorus to the growing plant.
Collaborators:
Mr Chris Guppy*, School of Land and Food Sciences, UQ
Dr Phil Moody, QDNRM, Indooroopilly
Dr Mike Bell, QDPI, Kingaroy
Duration of Project: 1996-2002
Funding Agency:
ACIAR
Soil fertility management for meeting the nutrient requirements of root crops in the north of Vietnam
Dr Jane O’Sullivan
This two-year project, which began on 1 July 2001, is part of AusAID’s “Capacity-Building in Agricultural Research and Development” (CARD) program for Vietnam. The project aims to improve soil fertility management for production of root crops (sweet potato and cassava), in the Soc Son District of Vietnam, through the cooperation of researchers, extensionists and farmers. The focus is on farmer-participatory research, alongside farmer training programs. Activities include (i) a short course training of researchers and extensionists in crop nutrition and in participatory technology development (September – October 2001), (ii) on-station characterisation of soils in the project area, using laboratory analyses and small pot experiments, (iii) completion of pilot farmer field schools, and (iv) appropriate on-farm, farmer-managed research trials. The technology is non-prescriptive, focussing on improving processes for identifying and solving soil fertility problems and for training farmers as soil fertility managers.
Collaborators:
Dr. Nguyen Cong Vinh, National Institute for Soils and Fertilisers, Hanoi, Vietnam
Mr. Dao Huy Chien, Root Crops Research Centre, Vietnamese Institute of Agricultural Science, Hanoi, Vietnam
Emer. Prof. Colin Asher, School of Land and Food Sciences, UQ
A/P Pax Blamey, School of Land and Food Sciences, UQ
Duration of Project: 2001-2003
Funding Agency:
AusAID
Detection and amelioration of potassium deficiency in rainfed cropping systems
A/P David Edwards and A/P Neal Menzies
Since cropping began in the Kingaroy district, farmers have relied upon the natural K supply in the soil. This practice has resulted in the depletion of the soil reserves of K and a marked stratification of the remaining K in the profile. In recent years, crops have shown symptoms of K deficiency during dry periods as their roots are unable to access the pool of K remaining in the surface soil. Farmers are reluctant to use high fertiliser K rates because they believe that K may interfere with pod set in peanuts.
This project aims to develop methods of applying fertiliser K so that it is readily available for the crop’s short growth cycle. Methods of measuring available K give conflicting results and they need to be improved. In addition, the interactions of K with the soil types in the district need to be understood. Despite the presence of highly weathered materials, the soils show marked fixation of K, which is normally associated with less weathered soils containing 2:1 layer silicate minerals. The interactions of K with Ca and Mg will be examined also in this study.
Collaborators:
Mr Jason Perna*, School of Land and Food Sciences, UQ
Dr Mike Bell, QDPI, Kingaroy
Dr Phil Moody, QDNRM, Indooroopilly
Duration of Project: 2002-2006
Funding Agencies:
APA
GRDC project in QDPI
Improved heavy metal management on farm and in recycling mill by-products
A/P Neal Menzies
Heavy metals in soils pose a significant health risk. While metals like zinc and copper are essential micronutrients for plants and animals, others such as cadmium and lead have no obvious biological function. Cadmium toxicity can occur at very low levels. Studies of soils in the Queensland sugar-growing belt have identified cadmium and zinc as potential health risks.
The main objectives of this study are to provide quantitative data on the concentrations and fractionation of heavy metals within the soil profile and to examine their bioavailability to plants grown in sugarcane soils. The two possible sources of heavy metal accumulation in these soils are mill mud and ash application and the practice of trash blanketing during cane harvesting. Mill by-products are often applied as a cheap source of nutrients; however, they also contain significant quantities of cadmium, mercury and zinc, which are concentrated where the mill mud is applied. Trash blanketing has eliminated the dispersion of heavy metals through volatilisation or ash dispersion when cane was previously burnt prior to harvesting. Sequential acid extraction techniques are being applied to sugarcane soils to give some indication of the forms in which cadmium and zinc are present. These tests are being followed by short-term plant growth bio-assays and by ion exchange resin methods and chemical speciation of extracted soil solutions that will lead to better predictions of cadmium and zinc availability.
Collaborators:
Ms Bennendine Woods*, School of Land and Food Sciences, UQ
Mr George Rayment, QDNRM, Indooroopilly
Mr Glen Barry, QDNRM, Indooroopilly
Duration of Project: 1999-2003
Funding Agency:
CRC for Sustainable Sugar Production
Effects of high magnesium groundwater on soil chemistry and sugarcane yield and quality
A/P Neal Menzies
The sub-basaltic aquifer to the east of Bundaberg yields water dominated by magnesium and, to a lesser extent, sodium ions. Some 2500 ha, in which sugarcane is the dominant land use, are irrigated with these waters. Preliminary studies have demonstrated a clear linkage between water quality and the balance of calcium and magnesium on the soil cation exchange complex. Leaf potassium levels in sugarcane were slightly below the critical value and calcium based soil ameliorants successfully modified soil calcium/magnesium imbalances, but without any impact on crop yield. The present studies are investigating further the effect of up to 20 years irrigation with high magnesium groundwaters on the soil chemistry and the effect of these changes on sugarcane yield and quality.
Collaborators:
Ms Judy Skilton*, School of Land and Food Sciences, UQ
Dr Bob Aitken, BSES, Harwood Island, NSW
Dr Graham Kingston, BSES, Bundaberg
Dr Bernard Schroeder, BSES, Indooroopilly
Duration of Project: 1998-2002
Funding Agencies:
CRC for Sustainable Sugar Production
BSES
Influence of climate and land use upon soil organic carbon sink, source and turnover in the sub-tropics of Queensland, Australia
A/P Neal Menzies
The aim of this project is to quantify carbon pools in soils of the Australian tropics under forests, and native and introduced grasses, and after tree clearing for grazing and cultivation for cropping. A number of classical wet-chemical methods will be used to obtain data on the total sink and source of organic carbon in these soils. This information will provide a benchmark in different ecological zones for planning National Greenhouse Resource Strategy as well as different land use practices for ecologically sustainable development. An additional aim is to estimate turnover rates of carbon in whole soils and in different carbon fractions, following separation based on density and sedimentation techniques. The data will help clarify best practices for different land use with a particular focus on the effects of tree clearing on carbon dynamics. It is also planned to enter the experimentally derived carbon dynamics data into an existing model for correlation with conceptual carbon pools in soil. The outcome will improve the parameters used in the model and extend the usefulness of the data in space and time. The outcomes could then be used in policy decision for both the greenhouse gas challenge program and for ecologically sustainable development.
Collaborators:
Mr Andrew Cramp*, School of Land and Food Sciences, UQ
Mr Graham Kerven, School of Land and Food Sciences, UQ
Dr Ram Dalal, QDNRM, Indooroopilly
Duration of Project: 1999-2003
Funding Agencies:
ARC SPIRT Grant
APA (I)
Subsoil ammonium accumulation in southeastern Queensland: origin, distribution and potential as a nitrogen supply to the agricultural sector
A/P Neal Menzies
High concentrations of ammonium nitrogen, up to 270kg N/ha, have been observed between 1.2 and 3 m in a Vertisol near Warra in southeastern Queensland. Given that nitrogen is often one of the most limiting nutrients for plant growth, this large reservoir of ammonium would represent a valuable resource to the agricultural sector if it could be recycled into the surface layers of the soil profile through, for example, the incorporation of deep-rooted species into cropping rotations. However, the original source of the ammonium is unknown, and it is not known whether deposits of subsoil ammonium are widespread across the region. Consequently, the aim of this project has been to identify the source of the ammonium at Warra, and use this information to identify other sites containing elevated ammonium at depth. If significant accumulations of ammonium are identified, this information will then enable the identification of agricultural species that can be incorporated into cropping rotations to help landholders access subsoil nitrogen for crop growth.
Collaborators:
Ms Kathryn Page*, School of Land and Food Sciences, UQ
Dr Ram Dalal, QDNRM, Indooroopilly
Dr Wayne Strong, Leslie Research Centre, Toowoomba
Duration: 1999-2002
Funding Agency:
GRDC
Factors influencing the retention of nitrate at depth
A/P Neal Menzies
Nitrogen fertilisers are extensively used to supplement natural levels of nitrogen in intensive agriculture. The three main methods of N loss from the soil are ammonia volatilisation, leaching through the soil profile and run-off. Preliminary experiments have suggested there is an imbalance in the export of N between paddock scale and catchment scale experiments, with the N exported over the whole catchment corresponding to that lost due to run-off at the paddock scale. This has suggested that N is being retained in the soil profile as a product of the leaching process; thus, large reserves of nitrate are present 5.5-7.5 m below long term sugarcane land.
The project will determine the mineralogy of soils from areas where the nitrate bodies have been located in order to determine the minerals present and the origin of the positive charge. An investigation of the chemical and physical properties which influence the positive charge will follow; these include CEC, AEC, soil pH, ionic strength and the mobility series of anions in the soil. The presence of cations and their effects on mobility of anions will be determined. The above factors will need to take into account the presence of a perched water table which develops during the wet season and the role of groundwater in the removal of nitrate. Further work will determine how different cropping regimes on the same soil type affect the development of high nitrate levels at depth.
Collaborators:
Mr Michael Donn*, School of Land and Food Sciences, UQ
Dr Gavin Gillman, CSIRO, Townsville
Dr Velu Rasiah, QDNRM, Innisfail
Duration of Project: 1999-2003
Funding Agency:
SRDC
The salt and water balance of a land application system for a highly saline industrial effluent
A/P Bing So and A/P Neal Menzies
This research will focus on the treatment and disposal of industrial effluent from the Leiner Davis Gelatin plant, which is located near Beaudesert, Queensland. The effluent contains high concentrations of salt, and ammonium and nitrate nitrogen, and is used to irrigate grasses and tree plantations in an effort to develop a sustainable disposal system. The main objective of this project is to determine the role of salt and water balance towards achieving a sustainable system. The research will focus on the use of a tree plantation as a possible component of a landscape assimilation process. Two main species, viz. Eucalyptus tereticornis and E. molucana have been planted at a low density (1100 trees ha-1) and a high density (2200 trees ha-1) approximately one year before commencing this study. The salt and water, as well as biomass production and leaching requirements will be studied in detail, while the relationship between sodium adsorption ratio and exchangeable sodium percentage in different soil types will be the focus of parallel laboratory studies.
Collaborator:
Miss Kylie Holmes*, School of Land and Food Sciences, UQ
Duration of Project: 2002-2006
Funding Agencies:
APA (I)
ARC Linkage Grant
Gross nitrogen balance of effluent irrigated agroforestry at Leiner Davis Gelatin plant
Dr Peter Dart and A/P Neal Menzies
Land is being increasingly used for the disposal of urban and industrial waste water, largely because of the high costs of alternative treatment or disposal systems. The Leiner Davis Gelatin plant at Beaudesert, Queensland takes in cattle hides from around Australia and extracts collagen, which is then converted to gelatin. The effluent produced by this process contains high concentrations of N, Ca and sulfate; it is currently irrigated onto 105 ha of grazing land surrounding the plant. Leiner Davis aims to regulate a deep leaching system so that the soil is used as an effective filter for nitrate, while allowing vertical movement of salts into the groundwater. A major challenge for disposal of this effluent is to use a sufficiently high irrigation rate to leach the applied salt but to ensure that N does not leach from the soil profile. An acceptable off-site outcome will be reached only if the N concentration in both the leachate reaching the groundwater and runoff reaching the Logan River is below the ANZECC guideline for freshwaters. This project aims to determine the N balance resulting from the use of Leiner Davis effluent for irrigation. The uptake of N by plants, and the losses of N through denitrification will be important considerations in the N balance determination.
Collaborator:
Miss Chloe MacDonald*, School of Land and Food Sciences, UQ
Duration of Project: 2002-2004
Funding Agencies:
APA (I)
ARC – Linkage Grants
Toolkits to predict and manage water quality from non-sewered subdivisions
A/P Neal Menzies
The fate of pollutants originating from on-site sewage treatments systems (OSTS) is not fully understood and often assumed when assessing the impacts on soils and water within a catchment. Council approval requirements for the installation of OSTS throughout SE Queensland are fragmented and inconsistent. The current research will begin to quantify the fate and attenuation of these pollutants in the immediate environment and at a catchment level, to ultimately assist in standardising the approval process and ongoing management of OSTS in SE Queensland. It will be primarily based on controlled studies of N, P and pathogen transformations in the effluent residual from absorption trenches and irrigation areas. It will involve interaction with local councils from whom it is hoped to obtain records including those of GIS mapping of non-sewered areas with overlays of allotments, slope, soils, geology etc. An existing DNRM model will be modified in an attempt to describe catchment scale behaviour of pollutants from OSTS non-sewered areas.
Collaborators:
Ms Cara Beal*, School of Land and Food Sciences, UQ
Dr Jim Sands, School of Agriculture and Horticulture, UQ
Mr Ted Gardner, CIRM
Duration of Project: 2002-2006
Funding Agencies:
CRC for Coastal Zone, Estuary and Waterways Management
CIRM
D. Rehabilitation of Mined Lands
Post-mining landscape parameters for erosion and water quality control
A/P Bing So and Prof. Clive Bell
The design of a post-mining landscape which achieves the prescribed erosion and run-off water quality standards set by regulatory authorities poses a significant problem for the open-cut coal mining industry. The use of drag-lines results in a landscape consisting of a series of parallel spoil piles with slopes of approximately 75%. To stabilise these spoil piles against erosion, they must be reshaped; however, reshaping is expensive and represents the major cost of any rehabilitation program. This research program has successfully defined the crucial landscape parameters (degree, length of slope, and vegetative cover) for erosion control and thereby reduced the costs of spoil handling needed to achieve a stable landscape.
The program involves the coordination of research at the laboratory and field scale, including:
- examination of the factors which contribute to the development of erosion and concomitant salt release problems and the measurement of soil and spoil erodibilities in the laboratory using a rainfall simulator and tilting flume; the development of the MINErosion and SaltRO models.
- measurement of erodibility of materials at 15 open cut coal mines with a portable rainfall simulator. The field simulation studies have also assessed the effects of vegetation on infiltration and erosion; this has led to development of the PERFECT-GRASP-MUSCLE (PGM) module.
- assessment of sediment, water and salt movement under natural rainfall on instrumented plots and catchments at three representative mine sites in the Bowen Basin.
- validation for erosion from catchments of a landscape evolution model (SIBERIA) from the University of Newcastle and its linkage to earthworks design packages such as ARGUS, MINCOM and VULCAN.
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Collaborators:
Dr Gary Sheridan* ,School of Land and Food Sciences, UQ (now DNRE, Heidelberg, Victoria)
Dr Robert Loch, Landloch Pty Ltd, Toowoomba
Mr Chris Carroll*, QDNRM, Rockhampton
Mr Michael Short*, School of Land and Food Sciences, UQ
Dr Tom Aspinall, School of Engineering, UQ
Dr Gary Willgoose, Dept of Civil Engineering and Surveying, University of Newcastle
Duration of Project: 1992-2003
Funding Agencies:
ACARP
Curragh Queensland Mining Ltd
BHP Coal Pty Ltd
Callide Coalfields Pty Ltd
Capricorn Coal Management Pty Ltd
MIM Holdings Ltd
Pacific Coal Pty Ltd
Factors limiting plant root growth in highly saline and alkaline bauxite residue
A/P Neal Menzies
Residues from the processing of bauxite are highly saline and alkaline and pose a significant threat to the surrounding areas. After completion of the mining operation, these residues must be capped and revegetated to a satisfactory condition and be self-sustaining. Leaching from rainfall will slowly improve these conditions and render them less hostile to plant roots. There is very little information available on the ability of roots from native vegetation to tolerate these saline and alkaline conditions and this project aims to investigate the tolerance of plants and their ability to grow on these hostile conditions, the processes of cycling, and the movement of these nutrients.
The effects of several factors on the growth and function of plant roots will be studied, including high pH, root calcium (Ca2+) requirement and exchange, aluminate toxicity, the effect of rhizospheric pH changes on nutrient availability, and the effect of soil properties on root distribution in residue sand.
Collaborators:
Mr Peter Kopittke*, School of Land and Food Sciences/CMLR, UQ
A/P Bing So, School of Land and Food Sciences, UQ
Dr David Mulligan, CMLR, UQ
Mr Ian Fulton, Environmental Section, Nabalco Pty Ltd
Duration of Project: 2001 – 2004
Funding Agency:
Nabalco Pty Ltd
An assessment of material handling characteristics of capping materials for Nabalco refinery, NT
A/P Bing So and A/P Neal Menzies
Nabalco Pty Limited currently produces approximately 2 MT/year of bauxite residue at its Gove-based alumina refinery. This material is an unsuitable plant growth medium due to its high sodium content, high pH and low hydraulic conductivity. Present rehabilitation practices at Gove involve capping the residue with soil to facilitate the establishment of vegetation. The transport of capping materials to the residue disposal area presently involves the use of excavators and dump trucks. Nabalco is assessing alternative and cheaper transportation systems including the use of soil slurrying. Such an option would utilise the existing infrastructure that is presently used to transport residue to the disposal area.
The objectives of this research program are to: (1) assess the physical impacts of pumping on the structure of Gove soils, (2) investigate the relationship between energy input and structural decline, and (3) determine potential soil amendments to reverse structural decline. These objectives will be met through laboratory and glasshouse experiments at UQ, with a field trial under consideration to verify outcomes at Nabalco’s residue disposal area at Gove.
Collaborators:
Mr Simon Buchanan*, School of Land and Food Sciences, UQ
Dr John Morrell, CMLR, UQ
Duration of Project: 2001-2003
Funding Agency:
Nabalco Pty Limited
Flow modelling and salt-water balance at the Gove bauxite refinery
A/P Bing So
Disposal of the bauxite residue is a major environmental concern in alumina production. At Gove, this residue is disposed of using the recently developed ‘dry-stacking’ method. Revegetation of bauxite residue impoundments by soil capping has been attempted and initially good plant establishment has been reported. However, over time, capillary rise of sodium and alkalinity has degraded the soil cover layer. The bauxite residue consists of two size fractions that are commonly separated during the beneficiation process, viz. a fine fraction (‘red mud’) and a coarse sand fraction. The latter has physical characteristics which make it attractive for use as a soil replacement in rehabilitation, provided its high sodicity, salinity and alkalinity can be reduced. Studies at UQ and Nabalco have shown that the salinity and alkalinity of residue sand can be markedly reduced by irrigation with sea water; precipitation of CaCO3 and MgCO3 produces a residue of pH 8.0 to 8.5.
The research program involves detailed laboratory and glasshouse experimentation at UQ and involvement in a field trial at Gove. The latter will involve periods of intensive monitoring (e.g. to assess flush-out of salt early in the wet season), combined with analysis and modelling of data collected during routine monitoring. The 10 ha field trial site consists of a 1m layer of residue sand, neutralised in site by irrigation with sea water, covered by a thinner layer of soil material. The residue sand layer is intended to provide a capillary break to prevent upward movement of salt and alkalinity from the underlying waste during the wet season and to provide water storage to support plant growth during the dry season.
Collaborators:
Mr Matthew Pomeroy*, School of Land and Food Sciences, UQ
A/P Neal Menzies, School of Land and Food Sciences, UQ
Dr David Mulligan, CMLR, UQ
Dr John Morrell, CMLR, UQ
Duration of Project: 2001-2005
Funding Agencies:
Nabalco Pty Ltd
ARC Spirt Grant
APA (I)
Criteria for the establishment of effective capillary barriers
A/P Bing So and A/P Neal Menzies
An integral aspect of mine site reclamation involves the establishment and growth of plant communities. Metal mine wastes present challenges in plant establishment and survival due to a combination of their physical, chemical and biological properties. Of particular importance is the upward movement of water, salt and toxic elements into the root zone. This has been responsible for failing to achieve a sustainable floral community in a number of instances. A possible solution to prevent water movement through the soil involves exploiting differences in texture and associated soil-water potential versus conductivity relationships between contrasting soil layers. Such arrangements have been termed capillary barriers and can be used to influence both upward and downward liquid water flow. Research is being conducted to examine and define the criteria necessary to successfully implement a capillary barrier to prevent the upward movement of water to the soil surface, and the leaching of undesirable elements to the groundwater or into waterways. Laboratory derived data will be compared with an intensively monitored field site as part of a larger project studying revegetation strategies for a bauxite mining operation in northern Australia. Monitoring includes the use and extension of modern methods of water and electrical conductivity determinations.
Collaborators:
Mr Ross Bigwood*, School of Land and Food Sciences/CMLR, UQ
Dr David Mulligan, CMLR, UQ
Dr John Morrell, CMLR, UQ
Mr Ian Fulton, Environmental Section, Nabalco Pty Ltd
Duration of Project: 1997-2002
Funding Agencies:
APA (I)
Nabalco Pty Limited
Bioavailability of heavy metals in mine spoils and contaminated soils
Dr V. Manoharan and A/P Neal Menzies
Measuring and understanding the transport, fate and bioavailability of metals in the environment are integral parts of assessing the overall risks that metals or metal compounds pose to the environment. The success of bioremediation and contaminated site rehabilitation is largely dependent on the accuracy of predicting the bioavailability of metal contaminants in both the short and long-term. There are few analytical methods specifically designed for the analysis of industrially contaminated land. Consequently, methods developed for the assessment of metal levels in agricultural soils are frequently used. However, these methods do not take into account the particular problems inherent within contaminated land, which include a large degree of site and sample heterogeneity and potentially high levels of co-contaminants which may ultimately compromise the accuracy of existing methods. Current research aim is to develop a test that accurately assesses the bioavailability of heavy metals to plants from contaminated soils and mine wastes with varying metal content, composition and remediation history. Experiments are being undertaken to both assess the suitability of existing methods and to test new methods to predict metal bioavailability. In addition to the chemical methods, short-term plant bioassays are also being undertaken to evaluate their suitability in estimating metal bioavailability. Future research will focus on the potential of using in situ resin methods, non-destructive solid phase methods and microbial bioassays to evaluate short and long-term metal bioavailability in field conditions.
Collaborators:
Prof. Clive Bell, ACMER
A/P David Edwards, School of Land and Food Sciences, UQ.
Dr. David Mulligan, CMLR, UQ.
Dr. Peter Glazebrook, Rio Tinto
Mr. Nicholas Currey, Kidston Goldmines Ltd
Ms. Zhi Ling Zeng*, CMLR, UQ.
Duration of Project: 2000-2002
Funding Agencies:
BHP Billiton,
Placer Dome Asia Pacific Limited,
Rio Tinto,
WMC Resources Ltd.
Copper bioavailability in mining contaminated waters
A/P Neal Menzies
Copper is a common contaminant in mined land, and an essential nutrient for plant growth. At excessive levels, it may be toxic to vegetation employed in rehabilitation. The metal exists in the environment in a number of forms (e.g. Cu2+, inorganic complexes, organic complexes and a colloidal bound fraction). However, only selected species are available for direct plant uptake. Current heavy metal risk assessment procedures and environmental regulations are often based on total or dissolved metal content, which has little correlation with phytotoxicity. Metal speciation at equilibrium, particularly the free ion activity in solution, appears to govern the extent of copper bioavailability and toxicity under specific conditions.
Numerous techniques have been developed to predict plant metal uptake, yet none has gained wide acceptance. The overall objective of this project is to develop or identify accurate methods for the assessment of copper bioavailability in contaminated waters. Currently, we are working on an integrated approach combining chemical measurement and modelling techniques in conjunction with a microbial bioassay using the freshwater alga, Chlorella sp. to assess copper bioavailability in water samples.
Collaborators:
Ms Zhi Ling Zeng*, School of Land and Food Sciences, UQ
Mr Graham Kerven, School of Land and Food Sciences, UQ
Prof. Clive Bell, School of Land and Food Sciences, UQ
Duration of Project: 1999-2002
Funding Agencies:
BHP
Placer Dome
Rio Tinto
WMC
Responses of Australian native species to heavy metal toxicity
A/P Neal Menzies, Em. Prof. Colin Asher and Dr David Mulligan (CMLR, UQ)
The mining process frequently results in substrates for rehabilitation that are high in heavy metals. Manganese, copper and zinc are three heavy metal elements that commonly cause toxicity problems for the rehabilitation of mined lands in Australia. This poses a serious limitation to the re-establishment of plants on these sites.
This research project has examined the effects of manganese, zinc and copper on Australian native tree species used in mined land rehabilitation. Experiments have determined toxicity symptoms and quantified relationships between growth depression, concentrations of the metal in the plant and concentrations of the metal in the growing medium. Other research has focussed on the potential ameliorative benefits of mycorrhiza and on the use of electron microscopic techniques to understand the toxic action of the metals on the native tree species. This project has provided diagnostic and ameliorative tools that will assist mines in overcoming the constraints on rehabilitation imposed by heavy metal toxicity.
Collaborator:
Ms Suzanne Reichman*, School of Land and Food Sciences, UQ
Duration of Project: 1997-2002
Funding Agency:
CMLR
Effects of mining disturbance on the ability of a Brown Kandosol to supply adequate phosphorus to re-establish vegetation
A/P Neal Menzies and Dr David Mulligan (CMLR, UQ)
The Brown Kandosols at Weipa, north Queensland, contain little soil phosphorus (P). Plant-available fractions approximate 85 mg P/kg soil, or 70% of the total soil P, the majority of which is held in labile organic forms, highlighting the importance of ‘P cycling’ in the native eucalypt forest. Mining disturbance breaks the natural P cycling processes and soil stripping and replacement severely reduces the size of the plant-available soil P fractions in surface (0-5cm) soils. This can only be partially compensated by the addition of P fertiliser. The restoration of P cycling is particularly slow, with the overall distribution of P within mixed replaced soils remaining different to that within undisturbed soils 15 years after rehabilitation to native forest or exotic pasture species.
Fertiliser P applied to the Weipa soil is rapidly adsorbed from soil solution, regardless of the degree of horizon mixing or rate of addition. Pure surface soils fertilised with 13 kg P/ha contain more plant-available P than those mixed-replaced soils provided with 52 kg P/ha. This confirms that practical rates of fertiliser P application cannot compensate for the adverse effects of profile mixing. Splitting P fertiliser applications to allow for a second, later application when roots have established was not an effective means of counteracting the soil’s high affinity for applied P.
Collaborator:
Mr Terrence Short*, School of Land and Food Sciences, UQ
Duration of Project: 1995-2002
Funding Agency:
Comalco Aluminium Ltd
Evaluating and testing wetland systems for treating waste water from coal mines in central Queensland, with particular reference to treating sulfate-rich water
Dr David Mulligan (CMLR, UQ) and Prof. Clive Bell
Waste water of varying quality is discharged from central Queensland coal mines; the quality problems include both low and high pH, high sediment load, high sodicity, high salinity, and elevated metal and sulfate loadings. Wetland systems have been used successfully for cleaning up contaminated waters at various sites around the world. They have the potential to significantly improve the quality of water for re-use or discharge. However, wetlands have not been evaluated in low rainfall/high evaporation environments as experienced in central Queensland.
This project to investigate the potential of wetlands to improve mine waste water quality in the Bowen Basin was instigated by BHP Australia Coal in 1993. Two pilot scale wetland systems were designed, constructed and operated at the Gregory Mine and the Crinum Mine. The major objective of the project is to isolate the factors that contribute to sulfate reduction in these wetlands. Sulfate reduction is expected to improve water quality by reducing sulfate levels, reducing total salinity, increasing pH and precipitating and removing heavy metals from the water column. A series of experiments has focussed upon limitations to sulfate reduction in the wetlands system; these include carbon supply (which may be inadequate or unavailable to the sulfate reduction bacteria), environmental conditions (e.g. pH), retention time, which may be inadequate for the bacteria to regenerate, and hydrology, which may short-circuit the reduction process.
Collaborators:
Ms Wendy Tyrrell*, BHP Coal Pty Ltd
Dr Lindsay Sly, School of Microbiology and Parasitology, UQ
Duration of Project: 1996-2003
Funding Agency:
BHP Coal Pty Limited
Investigating options for the rehabilitation of saline/sodic spoil on central Queensland coal mines
Dr David Mulligan (CMLR, UQ) and Prof. Clive Bell
Limitations to the successful re-establishment of self-sustaining and maintenance-free ecosystems on both Tertiary and Permian coal mine spoil in central Queensland include water availability, crusting, salinity and cover crop competition during the establishment phase, and compaction, water availability, nutrient availability and erosion during the growth phase. The major project on strategies for ecosystem development following coal mining in central Queensland had a number of sub-projects, including the effect of surface management practices on native species establishment on saline-sodic spoil.
Collaborators:
Mr Andrew Pearce*, School of Land and Food Sciences, UQ
Duration of Project: 1993-2002
Funding Agency:
BHP Coal Pty Limited
An assessment of mulch treatments to assist the re-establishment of native forest at Mount Owen Mine
Dr Sean Bellairs (CMLR, UQ) and Dr David Mulligan (CMLR, UQ)
The aim of this project was to examine the role of wood residue mulch in creating a favourable seedbed and microenvironment for the successful post-mining establishment and persistence of a range of native forest species that occur in Ravensworth State Forest in the Hunter Valley of NSW. This aim was addressed through the following specific objectives.
- quantifying the effect of mulch application on the physical characteristics of the soil replaced after mining;
- measuring the impact of mulch application on seed germination rates and seedling establishment;
- assessing the relationship and interactions between native seedling establishment, competing grass species and fertiliser application; and
- examining the influence of mulch application on the longer term processes of nutrient cycling and hence sustainability of the reconstructed forest communities.
Collaborators:
Ms Tamara Read*, CMLR and School of Land and Food Sciences, UQ
Dr David Lamb, Dept of Botany, UQ
Duration of Project: 1996-2002
Funding Agency:
Thiess Contractors Pty Limited
E. Plant Nutrition
Diagnosis and correction of nutritional disorders of yam
Dr Jane O’Sullivan and A/P David Edwards
This project aims to improve yield and profitability of yams, in those areas of the Pacific where they are important staple foods. Crop yields in the Pacific are under pressure from intensification of land use. Yams, which are traditionally grown first after the fallow due to their apparent high nutrient demands, are particularly susceptible to these pressures. However, yams are difficult to work with in an experimental context, and probably for this reason there has been little information on their nutritional requirements or on the diagnosis of nutritional disorders, prior to this project.
Three Pacific nations are involved in the project, viz. Tonga, Vanuatu and Papua New Guinea. Research includes surveys of crop health and of the socioeconomic context of yam production, on-station characterisation of soils from yam producing areas to quantify their nutrient deficits, and on-farm trials including fertilisers and alternative farming system approaches to improve yam nutrition and performance. Approaches include the use of legumes in the crop or fallow system and improved management of soil organic matter.
Work at The University of Queensland focusses on describing symptoms of deficiencies and toxicities of mineral nutrients, and on defining critical nutrient concentrations in leaf tissue. Initial work has revealed that yams are unusual in showing little translocation of the major nutrients, and as a consequence they do not seem to develop typical deficiency symptoms in the older leaves.
Collaborators:
Emer. Prof. Colin Asher, School of Land and Food Sciences, UQ
Dr. Siosiua Halavatau, Ministry of Agriculture and Forestry, Tonga
Mr. Jimmy Risimeri, National Agricultural Research Institute, Lae, PNG
Dr. Vincent Lebot, CIRAD and Vanuatu Agricultural Research and Training Centre, Vanuatu
Duration of Project: 1999-2003
Funding Agency:
ACIAR
The development of an interactive diagnostic key to disorders of sweet potato for CD-ROM and Web Media
Dr Jane O’Sullivan
Due to high demand internationally for the monograph “Nutrient Disorders of Sweet Potato”, published in 1997, this project was developed to provide diagnostic information for sweet potato using interactive, computer-based media. In addition to nutritional disorders, pests and diseases are also covered in the key, and information is also included on various aspects of sweet potato management and environmental factors affecting the crop. The key is based on “LUCID” software, developed by UQ’s Centre for Pest Information Technology and Transfer (CPITT). It utilises a “matrix key”, which allows the users to select whichever symptoms or signs they observe on a specimen, to reduce the number of possible causes. This is distinct from a dichotomous or pathway key, which requires choices to be made in a defined order. The key is supported by illustrated fact sheets on each subject, which are being contributed by a network of authors through collaboration with the International Potato Center (CIP) and the Philippines Rootcrops Research Institute (Philrootcrops).
The project includes collation of the key at UQ, and field testing in a number of countries with various user groups, including extension workers, students and researchers.
Collaborators:
Dr Geoff Norton, CPITT, UQ
Dr Elske Van de Fliert, International Potato Center (East and South East Asia Division), Bogor, Indonesia
Dr Jose Pardales, Philippines Rootcrops Research Institute (Philrootcrops), Visca, Leyte, Philippines
Duration of Project: 2001-2002
Funding Agency:
ACIAR
Effects of boron deficiency on flower development in canola and sunflower
Dr Adil Asad, A/P Pax Blamey and A/P David Edwards
Oilseed crops are important components of tropical, subtropical and temperate agriculture, as they provide easily available and highly nutritious human and animal food. One of the important soil constraints to canola and sunflower production is the low level of plant available boron (B) in soils both in Australia and in other countries around the world. These crops often suffer B deficiency, particularly around flowering time, severely limiting yield. The exact role of B is still not clear in flower growth and development, though it has been reported that B deficiency causes abnormal chromosomal separation during cell division and differentiation. Also, transportation of sugars to the developing flowers is disturbed by B deficiency, thereby reducing the sugar content of the nectar and decreasing pollen viability. The research will study the effects of B deficiency on flower development in oilseed crops grown in solutions with controlled external B concentrations. This will be accomplished using the recently developed technique of B buffered solution culture.
Duration of Project: 1999–2002
Funding Agency:
UQ Postdoctoral Research Fellowship
Boron nutrition of avocado crops
Emer. Prof. Colin Asher
The red volcanic and sandy soils in the north Moreton region of Queensland contain low levels of soluble B. Whilst there are avocado orchards in which trees display visible symptoms of B deficiency on the fruit and vegetative plant parts, and some large increases in fruit yield have been obtained following B application, the extent of the problem is not known. We have surveyed the B status of commercial avocado orchards and have conducted glasshouse and field experiments designed to refine existing diagnostic criteria for B deficiency of avocado and to develop methods and rates for B application to overcome these deficiencies. Marked effects of B nutrition on the yield of marketable fruit and on the storage and shelf life of avocado fruit have been demonstrated.
Collaborators:
Mr Timothy Smith*, School of Land and Food Sciences, UQ
Dr R.A. Stephenson, Maroochy Horticultural Research Station, QDPI, Nambour
Dr Suzan Hetherington, formerly School of Land and Food, UQ
Duration of Project: 1993-2002
Funding Agencies:
QDPI
HRDC
Potato internal tuber quality management in relation to environmental stresses
A/P Pax Blamey and A/P David Edwards
Internal disorders of potato tubers pose a serious marketing problem due to consumer resistance. The two major internal disorders are Brown Fleck, in which there is a brown discolouration of the tuber pith, and Hollow Heart, in which there is a large, open cavity within the tuber. Neither disorder has any external manifestation. These problems are especially severe in potatoes produced in the Lockyer Valley of Southeast Queensland.
The cause or causes of these internal disorders is not known, though various factors have been implicated (e.g. nutrition, high temperature and variable water supply). With regard to nutrition, calcium deficiency has been associated with increased incidence of Brown Fleck, and deficiencies of boron and zinc may play a role also. Temperature conditions and the supply of irrigation water have been implicated because of the large seasonal variation in the incidence of internal breakdown.
This project aims to identify the cause or causes of internal breakdown in potato tubers produced in the Lockyer Valley of Southeast Queensland, and to develop a management package that will limit the incidence of internal disorders in potato tubers. There will be a specific focus in the project on the effects of temperature and nutrition on potato tuber quality using both glasshouse and field experiments.
Collaborators:
Mr Stephen Harper*, QDPI, Gatton
Dr Ken Jackson, QDPI, Gatton
Duration of Project: 2000-2006
Funding Agencies:
QDPI
HRDC
Responses of linseed to vesicular-arbuscular mycorrhizae, phosphorus and zinc in a Vertisol
A/P David Edwards
The aim of this project was to determine the role that VAM play in the zinc and phosphorus nutrition of linseed grown on a Vertisol. A series of glasshouse experiments were designed to determine the response of linseed to jointly varying rates of P, Zn and mycorrhizal inoculum. Plants were grown in pots in the Vertisol which was partially sterilised by steaming at 70°C for 30 minutes. The high mycorrhizal dependency of linseed was confirmed. Without VAM, full growth potential of linseed required 400 mg P and 15 mg Zn kg-1 soil, while with VAM, good growth was achieved with 200 mg P and 7.5 mg Zn kg-1 soil. Dry matter yield of linseed was successfully modelled using soil extractable P and Zn levels and VAM inoculum level using a multiple Mitscherlich approach. The model allows prediction of potential responses or savings in P and Zn due to mycorrhizal colonisation in linseed roots. The savings in P and Zn fertiliser can be calculated.
Collaborators:
Dr John Thompson, Leslie Research Centre, Toowoomba
Mrs Nicole Seymour*, Leslie Research Centre, Toowoomba
Duration of Project: 1991-2002
Funding Agency:
ACIAR
The contribution of biological nitrogen fixation to the Australian sugarcane crop
Dr Peter Dart
Annual applications of up to 250 kg ha-1 of nitrogen fertiliser are common in Australian sugar cane production systems. Of this N fertiliser applied, up to 60% can be lost to the plant-soil system within the first 6 months after application, due to leaching, denitrification and mineralisation. Current sugar industry initiatives to develop sustainable nutrient management practices are aimed at minimising off-site effects and to ensure profitable production. As a result, alternative N sources are being investigated. The main focus of this research is to identify N2 fixing bacteria present in Australian sugarcane, establish the effect of cultivar and location on their numbers in different sugar cane tissues, define ecological parameters that influence potential N2-fixation and quantify the contribution of BNF to the N nutrition of sugar cane. Contribution to the N nutrition of the crop by these bacteria will improve the sustainability of the sugar industry by minimising loss of N off site, thereby reducing the environmental impact the sugar industry has on its surrounds and resulting in a more profitable and sustainable production system.
Collaborators:
Ms Suzanne Robertson *, School of Land and Food Sciences, UQ
Dr Graham Kingston, BSES, Bundaberg
Dr Sharon Brown, School of Land and Food Sciences, UQ
Duration of Project: 1999-2003
Funding Agencies:
APA
School of Land and Food Sciences
CRC for Sustainable Sugar Production
BSES
Phosphorus nutrition of ornamental native plants
Dr Margaret Johnston (Agriculture and Horticulture, UQ) and A/P David Edwards
Little information is available on the P absorption characteristics and internal P requirements of Australian native plants that are in the process of domestication. Growers mostly apply commercial horticultural rates of P, which have produced P toxicity symptoms in some varieties of Caustis spp. The project has focussed initially on comparing monocalcium phosphate (MCP) and the slower release rock phosphate as P sources for the growth of Caustis (two varieties), waxflower cv. Waneroo, and Sticherus at rates of application ranging from deficient to toxic. In particular, the two Caustis varieties grew better in the presence of rock phosphate than MCP at a rate of 176g P m-3 dry potting mix. As the rate of MCP application increased, Caustis continued absorbing P to toxic levels. A second experiment will determine the effects of soil P adsorption characteristics and P fertiliser solubility on growth and P acquisition of Caustis blakei var. M63. Six rates of rock phosphate and six rates of MCP will be applied to two soils of different P adsorption status in this experiment. Further work will examine the role of VAM in the acquisition of P by Caustis.
Collaborator:
Mr Daniel Gikaara*, School of Agriculture and Horticulture, UQ
Duration of Project: 2001-2003
Funding Agencies:
AusAID
School of Agriculture and Horticulture
The physiology of phophorus toxicity of Australian plants and the development of a molecular screening test for selection
Dr Margaret Johnston (School of Agriculture and Horticulture, UQ), Dr Susan Hamilton (Biochemistry and Molecular Biology, UQ) and A/P David Edwards
Most research on P acquisition by plants has focussed on P deficiency with very little research directed towards P toxicity; this is a barrier to the domestication and use of Australian plants throughout the world. Knowledge about the mechanism by which inorganic phosphate (Pi) is transported across the plasmalemma into the plant root cells has advanced recently through the application of molecular techniques. The expression of high-affinity Pi transporters appears to be regulated by the P status of the plant. Thus, in tomato, expression is increased when the supply of Pi is restricted. Conversely, re-supply of Pi results in down-regulation of Pi transporter expression. A number of additional proteins of unknown function are also down-regulated under P stress in plants such as soybean and Arabidopsis; these proteins include the metal-containing purple acid phosphatase. We hypothesise that the mechanism of down-regulation may be impaired in Australian native species such as Caustis blakei which is sensitive to P toxicity. cDNA clones of phosphate transporters and purple acid phosphatases from Caustis will be isolated, sequenced and compared with those isolated from other eukaryotes. Expression of these genes in phosphate-resistant and phosphate-sensitive strains of Caustis spp. will be examined by Northern blot analysis following growth in both high and low phosphate.
Collaborators
Mr Cameron Playsted*, School of Agriculture & Horticulture and School of Land and Food Sciences, UQ
Dr Carl Ramage, School of Agriculture & Horticulture, UQ
Dr Frank Smith, CSIRO Plant Industry, Indooroopilly
Duration of Project: 2001-2005
Funding Agencies:
UQ Research Development Grants Scheme
APA
School of Agriculture and Horticulture
Control of internal breakdown in mango fruit
A/P Pax Blamey
Internal breakdown in mango fruit is a major problem in many mango cultivars grown throughout the world, especially those originating from Florida. Two of the major cultivars grown in Australia, ‘Kensington Pride’ and ‘Keitt’, are amongst the susceptible cultivars to this disorder.
Internal breakdown is seen in many cultivars, but the incidence in Keitt is high and has been particularly severe over the past two seasons. Fifty percent of orchards have experienced significant problems and 25% have had severe problems. The disorder has led to a down-grading and dumping of the majority of fruit from the Keitt trees in the Mareeba area. The collapse of the late season Keitt mango market over the past 2 years has been attributed to internal breakdown. Prices for marketed crops were reduced by 30-50% as major buyers were wary of the disorder which cannot easily be detected until the fruit ripen. Any reduction in the incidence of internal breakdown will help restore market confidence in the cultivar.
Keitt is a late maturing cultivar used to extend the marketing season for most regions. It is the third most popular cultivar grown after ‘Kensington Pride’ and ‘R2E2’. In the Mareeba district, ‘Keitt’ makes up 10% of all trees grown.
This project will investigate the role of calcium, boron and excess vigour in internal disorder breakdown in Keitt. The information gained in this investigation will be directly applicable to other cultivars such as ‘Kensington Pride’ and to other growing regions. The project will be mainly carried out in the Mareeba district because of the severity of the problem in ‘Keitt’ growing on the granitic sandy soils.
Collaborators:
Mr Ian Bally*, QDPI, Ayr
Dr Peter Hofman, Maroochy Horticultural Research Station, QDPI, Nambour
Dr Tony Whiley, QDPI, Nambour
Duration of Project: 1997-2003
Funding Agency:
HRDC
F. Miscellaneous
Spatial prediction of soil properties from historic survey data using decision trees and conceptual modelling
A/P Bing So and Dr Robin Thwaites (formerly School of Land and Food Sciences, UQ)
The aim of this project was to develop effective approaches to the rapid prediction of functional soil attributes driving forest processes using environmental variables. The particular objectives were:
- to apply current developments in conceptual and statistical environmental modelling to the prediction of soil attributes,
- to integrate relevant databases of land resource information related to soil and regolith properties to produce spatial coverages of soil functional attributes important in forest growth and production,
- to develop innovative approaches in capturing the experiential knowledge of field scientists to use in conceptual models of soil processes, and
- to test the relative improvement in predictive models of forest distribution and performance that utilise soil attributes defined by the above procedures.
The study used GIS systems to spatially predict soil attributes, using soil landscape models developed using decision trees and a combined statistical and fuzzy logic conceptual modelling approach. The soil-landscape models were constructed using readily available regolith and terrain indices to model pedogenic processes and thereby predict soil attributes.
Collaborators:
Mr Justin Claridge*, School of Land and Food Sciences, UQ
Mr Michael Grundy, QDNRM, Indooroopilly
Prof. B.K. Slater, Ohio State University, USA
Duration of Project: 1999-2002
Funding Agency:
QDNRM
Improved establishment and growth of Australian native flora
Dr Peter Dart, Dr Helen Ogle and Dr Margaret Johnston (Agriculture and Horticulture, UQ)
The Australian Native Plant Industry has the potential to develop a viable commercial market, both domestically and internationally. Present commercial production is limited to a small number of species and varieties grown in nurseries and bush harvesting, which may have an environmental impact on natural habitats. There is a need to develop nursery propagation techniques to sustain the present markets; we need to understand the requirements for these plants in potting media, their nutrition and irrigation needs and their management of plant protection. Many Australian native plant species have a symbiotic relationship with ecto- and endo-mycorrhiza. It is believe that this relationship has enabled plants to grow in areas where the fertility and water status are low and that it may have protected plants from disease through biological control of plant pathogens.
This project has aimed to establish rhizosphere microbial populations which are beneficial to plant health and nutrition. Several ecto- and endo-mycorrhizal strains have been tested for compatability with selected Australian native plant species. These tests have involved plant growth at the nursery stage and following field establishment of nursery raised plants. There has also been a focus on plant health, following the establishment of a collection of virulent pathogens of the native plant species. These pathogens have been tested against biocontrol bacterial or fungal strains which inhibit growth of the pathogens on agar plates. Nursery inoculation procedures which give biocontrol of pathogens were then developed. Ultimately, it is hoped to develop an integrated package of practices which lead to the domestication of native plants.
Collaborator:
Ms Taryn Fletcher*, School of Land and Food Sciences, UQ
Duration of Project: 1998-2002
Funding Agency:
UQPRS
The relationship between physiological responses to biophysical environments and growth and wood production efficiency of two eucalypts in Queensland
Dr Peter Dart and Dr David Doley (Botany Dept., UQ)
Current forest planting in Queensland is concentrated in the humid coastal region with annual rainfall greater than 1000 mm. However, with increasing scarcity and cost of land suitable for commercial forestry, further expansion will only occur on lands subject to occasional drought (annual rainfall between 600 and 1000 mm) and unsuitable for Pinus species. There is limited knowledge of the plantation silviculture of native hardwood species. Eucalyptus argophloia Blakely and Eucalyptus cloeziana F. Muell. are among the most favoured commercial hardwood timber species in subtropical eastern Australia, because of their valuable timber, commonly used for furniture and flooring. However, a physiological understanding of the responses of these two species to soil water availability and temperature is lacking, so that it is difficult to predict species suitability to different sites.
Glasshouse experiments have been conducted to investigate the acclimation of photosynthesis to temperature, response of photosynthesis to different levels of water stress, partitioning of biomass under water deficit stress and leaf water relations. Field studies examining diurnal and seasonal patterns of photosynthesis and the associated gas exchange parameters, leaf water relations and biomass production and allocation on humid and subhumid climatic sites in southeast Queensland are in progress.
Collaborators:
Mr Michael Ngugi*, School of Land and Food Sciences, UQ
Dr Mark Hunt, QFRI, Gympie
Duration of Project: 2000-2004
Funding Agencies:
UQ Graduate School Award
School of Land and Food Sciences
QFRI
Wilf Crane Memorial Award
Comparative analysis of institutional arrangements supporting transfer of rural development expertise and technologies from industrialised to non-industrialised countries
Dr Abigail Makim and Dr Peter Dart
This project analyses institutional arrangements established in support of the transfer of rural development expertise and technologies from research institutions based in industrialised countries to partners based in developing countries. The project is exploring ways in which political and economic variables affect research partnerships working towards community development.
Case studies are based on: (1) tree production technologies for the Philippines and tropical Australia (ACIAR FST 96/110); (2) the North New Georgia sustainable social forestry and rural development project (Solomon Islands); and, (3) mixed species plantations of high-value trees for timber production and enhanced community services in Vietnam and Australia (ACIAR FST 2000/003).
The project is undertaking a comparative analysis of these technically similar but politically disparate case studies and is considering the role and influence of governments, intergovernmental organisations, non-government organisations, community based organisations, research organisations and commercial organisations in forming and maintaining sustainable research partnerships seeking community development.
Collaborator:
Mr Greg Young, Rural Development Trust Board
Duration of Project: 2001-2002
Funding Agency:
UQ Postdoctoral Fellowship
Production of rotifers (Brachionus rotundiformis) for use in fish hatcheries
Dr Peter Dart and Dr Donald Fielder (Zoology & Entomology, UQ)
Two main studies were conducted: (1) isolation of new tropical Australian microalgae species/strains which have potential as feed for aquaculture and, (2) evaluation of some tropical Australian algal species/groups as feed for the zooplankton, Brachionus rotundiformis commonly known as rotifers. Six microalgae were isolated locally. Among these isolates, 4 species/strain (Chlorella-like, Tetraselmis sp., 2 strains of Nitzschia sp.) were evaluated as feed to rotifers. Growth performance was best for rotifers fed Chlorella-like algae and intermediate for rotifers fed Tetraselmis sp.
In another study, growth performance and nutritional composition of rotifers fed three tropical Australian microalgae (Nitzschia palaceae, cryptomonad and Rhodomonas sp.) from the microalgal collections of Northern Territory University and CSIRO, Tasmania, Australia were evaluated. Growth performance was best for rotifers fed N. palaceae and intermediate for cryptomonad fed rotifers. There was a significant increase in the HUFA content of rotifers (from 2.1% initial HUFA to a range of 27 to 33% of the total fatty acids) after feeding on four microalgal species. This suggests a significant uptake of these fatty acids by the rotifers from their diets. The essential fatty acids EPA (20:4n-3) and DHA (22:6n-3) were both present in the rotifers fed four microalgal diets. DHA and EPA contents were highest for cryptomonad fed rotifers followed by N. palaceae fed rotifers. These essential fatty acids are crucial for growth and survival of cultured marine larval species in the hatcheries.
Collaborators:
Ms Mary Chona Estudillo*, School of Land and Food Sciences, UQ
Dr Frances D’Souza
Duration of Project: 2000-2001
Funding Agency:
AusAID