Irrigated cotton production in Australia is predominately (80%) based on furrow irrigation. Although significant improvements in furrow irrigation efficiency have been achieved over the last decade the inability to reduce run-times, due largely to (increasing) labour force constraints, has restricted potential gains. The principal focus of the Optimizing water and energy use in the CQ Irrigation Sector project will be the conduct of field trialling in the CQ region to contribute to development of techniques that will increase ability to automate furrow irrigation.

In addition the project will continue the focus of the recently terminated Central Highlands and Dawson-Callide irrigation districts RWUE 4 project i.e. provision of assistance to the irrigation sector to adapt to increased variability and energy costs likely to result from climate change and associated policy responses. Performance evaluations of pumping systems, a major component of irrigation energy use in many irrigation enterprises, and of furrow and overhead irrigation systems (particularly CPLM) will be conducted. Data from these will contribute to the development and promotion of industry benchmarks that are critical for achievement of future industry efficiency gains.

The project will also provide support for the increased uptake of myBMP, technical assistance to Fitzroy Basin Association where required, and promotion of awareness of tools and resources designed to assist achievement of increased efficiencies (e.g. CropWaterUse, WaterSched2, and the revised WATERpak).

Since 1999-2000 the Queensland Government has funded four Rural Water Use Efficiency programs across Queensland. These projects have primarily focussed on improving water use efficiency within the Cotton and Grains industries of Queensland. These projects resulted in significant improvements in the efficiency of irrigation within these industries. In the most recent project – RWUE4 – the focus has been on the assessment of the irrigation performance of centre pivot and lateral move machines in Central Queensland, and the development of the Growers Guide to Centre Pivots and Lateral Move DVDs.

The principal proposed focus (40%) for this project is to examine potential methodology for automation of furrow irrigation. In addition the project will continue to assist those within the irrigation sector to improve their water and energy efficiencies. Energy inputs represent a major and rapidly increasing cost to growers. On-farm energy efficiency is becoming increasingly important in the context of rising energy costs and concerns over greenhouse gas emissions. Pumping costs constitute a major component of irrigation system energy use.

Increased flexibility associated with automation of furrow irrigation (40% of the projects activities) has potential to play a critical role in enabling irrigators to adopt more precise scheduling methodology than currently possible with the predominate industry irrigation practise of manually set furrow syphons. In addition, automation could assist with the increasing difficulty faced by irrigators in sourcing labour.

The project provided valuable information regarding optimum downfield placement of the advance / depth sensor(s), and resolved a number of identified practical issues relating to placement and operation of sensors. This facilitates progression with evaluation trialling to be conducted in the current CRDC funded project. Interim analysis has provided encouraging results. suggesting a strong correlation between AutoSISCO predicted cut-off time (using a single advance point), and their associated outcomes in relation to irrigation efficiencies. As a result of the collaborative basis of the automation research (NCEA CRDC

project) many of the problems that are often associated with initial trialling were avoided. This was of great value in providing cost effective outcomes and progressing future research in an efficient manner.

Pumping constitutes a major energy cost in most irrigation systems. Previous evaluations have indicated the potential for significant improvements in many systems. Pumping system efficiency evaluations conducted by the project enabled comparison of measured performance to the theoretical best operating point (as identified on relevant efficiency curve graphs), and comparison of performance against an industry benchmark (using 5 kWhr/ML/m head). Where systems were identified as performing outside their optimum range, or at variance to the benchmark, growers were better equipped to make cost benefit analysis of options for improvement.

Historically performance evaluations results have indicated that many overhead irrigation systems were falling short of their expected performance efficiencies. In many cases, once identified, factors impeding efficient operation have been redressed via relatively inexpensive modifications. Evaluations conducted by the project provided valuable assistance in identifying the source of any problem and thus equipped the grower with information that could be used to rectify issues of poor performance.

The project continued working closely with the local irrigators and the community in general providing resources pertaining to water use and energy use efficiency. This has facilitated an enhanced awareness of industry wide efforts and has equipped the local growers with the options to improve the viability of their operations.

The recently funded CRDC project, now underway, will sustain this projects impetus by continuing to assist local irrigators address the challenges inherent in maintaining sustainable cotton production in the face of a changing environment.