Strategies for maximizing sugarcane yield with limited water in the Bundaberg district

Between 1995 and 2003 sugarcane farmers in Bundaberg had access to limited irrigation water. Over this time water allocations were effectively a quarter of the requirements for a fully irrigated crop. In response to this problem irrigation strategies were developed to assist farmers. Field investigations focused on the performance of water winch and furrow irrigation systems, which make up 91 percent of the irrigated area in the district. As most of these application systems have insufficient capacity to meet crop demands, opportunities to schedule irrigations were limited to start up after rain. Improvements in irrigation system performance were found to provide the greatest potential to increase sugarcane yield under conditions of limited water. Investigations identified that irrigation performance could be significantly improved through relatively minor adjustment. Timing of irrigation start up after rain influenced how much water could be applied to the field. Even with relatively low allocations delayed start up strategies could lead to a situation where water was left over at the end of the season

The future direction of on-farm irrigation technologies and practice research

The Cooperative Research Centre for Irrigation Futures mission is to facilitate cooperative research and training networks and programs which continuously improve irrigation policy, tools, practices and processes. This paper provides an introduction to the current and planned research activities within the CRCIF with a particular focus on the tools and practices of relevance to improving on-farm water use efficiency. A key focus of this research is the delivery of research outcomes via toolkits which enhance the irrigation sector's ability to measure, monitor and manage the water balance at the field and farm scales, improve the precision of in-field irrigation applications and maximize agronomic responses to irrigation

Mapping and analysis of changes in the riparian landscape structure of the Lockyer Valley Catchment, Queensland, Australia

[Abstract]: A case study of the Lockyer Valley catchment in Queensland, Australia, was conducted to develop appropriate mapping and assessment techniques to quantify the nature and magnitude of riparian landscape structural changes within a catchment. The study employed digital image processing techniques to produce land cover maps from the 1973 and 1997 Landsat imagery. Fixed and variable width buffering of streams were implemented using a geographic information system (GIS) to estimate the riparian zone and to subsequently calculate the landscape patterns using the Patch Analyst (Grid) program (a FRAGSTATS interface). The nature of vegetation clearing was characterised based on land tenure, slope and stream order. Using the Pearson chi-square test and Cramer’s V statistic, the relationships between the vegetation clearing and land tenure were further assessed. The results show the significant decrease in woody vegetation areas mainly due to conversion to pasture. Riparian vegetation corridors have become more fragmented, isolated and of much smaller patches. Land tenure was found to be significantly associated with the vegetation clearing, although the strength of association was weak. The large proportion of deforested riparian zones within steep slopes or first-order streams raises serious questions about the catchment health and the longer term potential for land degradation by upland clearing. This study highlights the use of satellite imagery and geographic information systems in mapping and analysis of landscape structural change, as well as the identification of key issues related to sensor spatial resolution, stream buffering widths, and the quantification of land transformation processes

Simulation of site-specific irrigation control strategies with sparse input data

Crop and irrigation water use efficiencies may be improved by managing irrigation application timing and volumes using physical and agronomic principles. However, the crop water requirement may be spatially variable due to different soil properties and genetic variations in the crop across the field. Adaptive control strategies can be used to locally control water applications in response to in-field temporal and spatial variability with the aim of maximising both crop development and water use efficiency. A simulation framework ‘VARIwise’ has been created to aid the development, evaluation and management of spatially and temporally varied adaptive irrigation control strategies (McCarthy et al., 2010). VARIwise enables alternative control strategies to be simulated with different crop and environmental conditions and at a range of spatial resolutions. An iterative learning controller and model predictive controller have been implemented in VARIwise to improve the irrigation of cotton. The iterative learning control strategy involves using the soil moisture response to the previous irrigation volume to adjust the applied irrigation volume applied at the next irrigation event. For field implementation this controller has low data requirements as only soil moisture data is required after each irrigation event. In contrast, a model predictive controller has high data requirements as measured soil and plant data are required at a high spatial resolution in a field implementation. Model predictive control involves using a calibrated model to determine the irrigation application and/or timing which results in the highest predicted yield or water use efficiency. The implementation of these strategies is described and a case study is presented to demonstrate the operation of the strategies with various levels of data availability. It is concluded that in situations of sparse data, the iterative learning controller performs significantly better than a model predictive controller

Spatial prioritisation of revegetation sites for dryland salinity management: an analytical framework using GIS

[Abstract]: To address the lack of analytical and modelling techniques in prioritising revegetation sites for dryland salinity management, a case study of the Hodgson Creek catchment in Queensland, Australia, was conducted. An analytical framework was developed, incorporating the use of spatial datasets (Landsat 7 image, DEM, soil map, and salinity map) which were processed using image processing techniques and a geographic information system (GIS). Revegetation sites were mapped and their priority determined based on recharge area, land use/cover and sub-catchment salinity. The analytical framework presented here enhances the systematic use of land information, widens the scope for scenario testing, and improves the testing of alternative revegetation options. The spatial patterns of revegetation sites could provide an additional set of information relevant in the design of revegetation strategies

Improving whole farm and infield irrigation efficiencies using Irrimate tools

Whole farm irrigation water includes all pumped, delivered, captured, distributed and/or stored water within the farm gate. Utilisation of rainfall, recycled irrigation water, and harvested overland flows are included in the on-farm water volume. In assessing the performance of on-farm irrigation systems it is necessary to recognise that there are both agronomic and volumetric components of the system and that both contribute to the overall productive output. Evaluation of irrigation performance at the whole farm scale using total volumetric inputs and total production outputs provides a benchmark for comparative purposes but fails to provide an adequate diagnostic tool to identify either the source of inefficiencies or appropriate strategies to improve performance. Hence, diagnostic performance evaluation requires the measurement of the inputs and outputs for each sub-component of the system in a way which enables the partitioning of losses and the identification of the importance of specific loss mechanisms

Quantifying landscape fragmentation in the Lockyer Valley Catchment, Queensland: 1973 – 1997

Fragmentation has become a central issue in landscape ecology and conservation. The breaking up of large land areas into smaller patches is known to influence many ecological patterns and processes. Thus, landscape fragmentation needs to be assessed and monitored. In this study of the Lockyer Creek Catchment in Queensland, landscape fragmentation was quantified using 1973 and 1997 Landsat images and other thematic layers. Landscape metrics (focusing on the size, shape, density, and isolation of woody vegetation) were calculated using the Patch Analyst (Grid) extension of ArcView GIS. The nature of fragmentation was further characterised based on landscape features including land use/cover, tenure, slope, as well as distance to roads and streams

A scoping study on measuring and monitoring tools and technology for precision irrigation

This scoping study is designed to advance high standards of precision in management of water and develop efficient methods of irrigation prescription to reduce losses and improve water use efficiency. All aspects of irrigation process are considered in this study to include various components of farm water storage and distribution systems to facilitate accurate accounting of water. In this study, we will attempt to: * Identify key attributes and specifications for various tools (sensors and control systems) for precision irrigation management; * Develop strategies to fill current gaps in the functionality of various tools and technology available for irrigation and * Prioritise opportunities to refine and/or develop new tools and technology to increase on-farm precision and meet off-farm hydrology needs

Primary healthcare provision and Chronic Fatigue Syndrome: a survey of patients' and General Practitioners' beliefs

BACKGROUND: The current study was conducted as part of a research project into the evaluation and assessment of healthcare provision and education in Chronic Fatigue Syndrome (CFS). One aim of the study was the development of informative and educational literature for both General Practitioners (GP) and sufferers. Issues such as diagnosis, management and treatment of the syndrome should be included in information booklets written by healthcare professionals. It was important to begin the process by assessing the level of specialist knowledge that existed in typical GP surgeries. This data would then be compared to data from CFS patients. METHOD: 197 survey booklets were sent to CFS sufferers from an existing research panel. The patients approached for the purpose of the study had been recruited onto the panel following diagnosis of their illness at a specialised CFS outpatient clinic in South Wales. A further 120 booklets were sent to GP surgeries in the Gwent Health Authority region in Wales. RESULTS: Results from the study indicate that the level of specialist knowledge of CFS in primary care remains low. Only half the GP respondents believed that the condition actually exists. CONCLUSION: Steps are recommended to increase the knowledge base by compiling helpful and informative material for GPs and patient groups