Automation and control in surface irrigation systems: current status and expected future trends

Surface irrigation systems are the most popular methods for irrigating crops and pastures not only in Australia but the world over. However, these systems are often labour intensive and exhibit low water use efficiency. Rising labour costs especially in the developed world and competition for scarce water resources have generated renewed interest in the automation of surface irrigation systems. This paper provides a comprehensive review of the current level of automation and control of surface irrigation systems. The automation techniques discussed utilise various devices including mechanical, electronic, pneumatic and hydraulic means. The use of telemetry is also discussed. With the almost universal access to high performance computers and fast internet, the concept of real-time control in surface irrigation is not far-fetched. Towards this end, an on-going research project at USQ aimed at modernising furrow irrigation by use of automatic control systems in real time is discusse

Improving performance of bay irrigation through higher flow rates

Bay (border check) irrigation systems are utilised extensively throughout the Goulburn Murray Irrigation District (GMID). However, the performance of these systems have rarely been assessed, in part due to the difficulty in determining the soil intake function. The CRC for Irrigation Futures has recently completed a project to demonstrate the Irrimate™ performance evaluation process in bay irrigation through on-farm trials. The Irrimate™ approach originally developed for furrow irrigation has already provided real benefits to farmers and has been accepted across the cotton industry. Bay irrigation has a number of unique characteristics which presented a number of challenges for the tools used to evaluate furrow irrigation. Informed by field trials, new monitoring strategies were tested and new modelling approaches developed in order to provide the same robust evaluation procedure for bay systems. Evaluations provide objective information to irrigators both quantifying efficiencies of current practices and providing strategies to improve performance. Trials were conducted across 11 sites in order to benchmark current performance and to examine the potential advantages of higher flow rates. Performance varied widely between sites with application efficiencies ranging from 45.9% to 89.5%. Initial modelling indicated that higher flow rates offer potential to increase efficiency. Trials in the second season confirmed the modelling work demonstrating water savings in excess of 20% through flow rates approximately double the conventional rates. The results also show that higher flow rates do not automatically lead to higher efficiency. When adopting higher flow rates irrigators must have greater control over cut-off times. System evaluation is an essential step to reap the benefits of higher flows. The results of this study provide objective information for the modernisation of irrigation systems in the GMID

Selection of irrigation duration for high performance furrow irrigation on cracking clay soils

The maximum efficiency attainable by furrow irrigation in any particular situation is determined largely by the soil infiltration characteristic and the flow rate onto the field. However the correct selection of irrigation duration (or time to cut-off) is necessary to realise optimum performance. As a result of previous work the cotton industry in Australia has increased furrow flow rates and reduced irrigation durations with the effect of raising average application efficiencies from a low 48% to now above 70%. This is the maximum that can be achieved under current management practices. Raising efficiency further can only come about by managing each irrigation (by varying flow rate and Tco) to give optimum performance for the prevailing conditions. The previous work has shown that applications in excess of 85% are possible by this means. A consequence is that greater accuracy and precision is required in the selection and management of irrigation durations. In this paper, various methods for estimating the optimal or preferred time to cut-off in real-time (while the irrigation is underway) are compared, namely, cut-off when the advance reaches a set distance, guidelines based on the advance rate, and real-time optimisation using hydrodynamic simulation. Simulations using historic data from two cotton fields show that there is little difference in the efficiencies achieved by the three methods. However, there is substantial difference in the data required by the different methods and in their robustness to inaccuracies in the data. These latter points will dominate selection of the most appropriate method for any particular situation

Irrigated agriculture responds to water use challenges

Presented at Irrigated agriculture responds to water use challenges - strategies for success: USCID water management conference held on April 3-6, 2012 in Austin, Texas.Includes bibliographical references.A system for the real-time optimization of furrow irrigation is described. The system estimates the soil infiltration characteristics in real-time and utilizes the data to control the same irrigation event to give optimum performance for the current soil conditions. The main features of the system are: the use of a model infiltration curve and a scaling process to describe the current soil infiltration characteristic; measurement of the inflow rate to the furrows; measurement of the water advance at a point approximately midway down the furrow; and a microcomputer running a hydraulic simulation program based on the full hydrodynamic model to predict the optimum time to cut-off. The system was trialed on a furrow-irrigated commercial cotton property utilizing pipes through the bank (PTBs) to supply groups of furrows. The initial observations from these trials are presented in this paper and demonstrate that improvements in water use efficiency are potentially achievable through the use of the system. Extensions to the system to improve its performance and to make it applicable to bay irrigation are described

High performance automated furrow irrigation

Furrow irrigation is the most popular irrigation method in cotton. However, two issues: low efficiency and huge labour involvement concern irrigators due to scarcity in recent years. To address these issues, NCEA and Rubicon Water, Australia are developing a commercial prototype smart furrow irrigation system. The system has shown that both issues disappear with adoption of real-time optimisation and automated furrow irrigation

A simple strategy to manage furrow irrigation efficiently

Cut-off time is vital in furrow irrigation as it significantly affects the efficiency of irrigation. Traditionally, irrigators continue the irrigation until the water reaches the end of the field. Simulation software can also be used to optimise cut-off time. However, first method is proven inappropriate and the latter method is complex. Hence, a simple method to determine cut-off time for farmers to manage furrow irrigation efficiently was evaluated and found to give cut-off times similar to the optimum time

Controlling surface irrigation using digital devices

Furrow irrigation is widely used and is the most popular irrigation method for row crops. In Australia this method is widely used (about 95%) for the irrigation of cotton, although it is labour intensive and traditionally has had low water use efficiency due to the significant amount of water losses through deep drainage and runoff. However, it is reported that a well-designed and managed furrow irrigation system may have application efficiencies up to 90% to 95% that would be similar to other more energy intensive efficient irrigation systems. Towards this, the National Centre for Engineering in Agriculture (NCEA) has been playing the leading role in the world since a long period of time and made a significant improvement in efficient furrow irrigation. Recent research at NCEA has established the foundation for the real-time control of furrow irrigation. It has developed the concept and tested the software required for the real-time optimisation and has shown its capability of sensing the inflow and advance, simulating the irrigation, and predicting the optimum time to cut-off without any user intervention. In partnership with technology company Rubicon Water, the NCEA has developed a smart automation system for controlling furrow irrigation using internet connected latest digital devices like smart phones, iPad, laptop or desktop from anywhere in the world. It involves flow control infrastructure, advance sensors, control software and wireless communications. Currently the NCEA is demonstrating this system in various locations in cotton growing region across Australia through a project funded by the Cotton Research and Development Corporation. The preliminary results show the potential of the system to save significant labour and water although there remain some limitations in water delivery system

Smart automated furrow irrigation of cotton

Over a number of years the cotton industry (CRDC) has been supporting NCEA in the development and demonstration of a system for the ‘smart’ automation of furrow irrigation. The system currently undergoing final trials consists of three major component parts. The core component is automation hardware and software initially developed for bay irrigation and which is available commercially from Rubicon Water under its FarmConnect system. This provides: • precise, automated control of flows throughout the farm from the source (channel or ring tank) to the field, and • sequencing of the irrigation of fields and sets according to a pre-programmed schedule. This system uses a communications gateway located in central location on the farm and communicates with each radio node attached to the various sensors and control structures using ZigBee radio technology. The second component is specifically designed flow control infra-structure that gives precise, automated control of flows into the furrows. This consists of a Rubicon automated BayDrive and flap gate installed in a standard box culvert, which delivers to the furrows via either: • small diameter (50 to 80mm) pipes inserted through the bank of a dedicated head-ditch. • a wide level rotabuck area. • flexible gated fluming. The final component is process for the real-time selection of time to cut-off for individual furrow sets to maximise application efficiency. Results from the demonstration trials have shown the system to work well without manual intervention. The evaluation of irrigation events controlled using the real-time optimisation show significant water savings over farmer managed irrigations. The future outcome of this work will be a commercial adaptive real-time furrow irrigation system able to compete with the pressurised alternative of centre pivot or lateral move machines on capital cost, water and labour savings but without the substantial energy costs

Evaluation of the performance of automated bay irrigation of pasture and fodder

Automation of surface (bay) irrigation is a commercial reality with a number of farms in northern Victoria adopting it for whole or part of their irrigated area. Automation provides increased certainty in irrigation management. However in the absence of appropriate decision support, most of the key decisions, such as the scheduling of irrigations, flow rate and irrigation duration, still rely on the skill of the irrigator. Over the 2013/14 irrigation season the authors were engaged to evaluate the application efficiency of automated bay irrigation. The trial involved 9 farms x 1 bay x multiple irrigations. Flow rate into the bay was inferred from measurements at the supply point to the farm. Irrigation advance down the bay and flow depth were measured at three points down each bay. Soil moisture was monitored continuously at a central point in each trial bay. Data were collected automatically and stored on-line. The results demonstrated that application efficiencies in excess of 90% are achievable and are being achieved through correct and precise management of the automated irrigation. Four of the farms evaluated in this study are already operating at that level. For another four of the farms strategies have been identified that will raise their efficiency close to or above 90%. On the remaining farm soil limitations preclude improvements in efficiency on the trial bay. As well a number of not unexpected lessons were learnt from the trial: 1. Excessively long irrigation durations are the principal cause of low efficiencies. 2. Soil moisture data is crucial for the optimal management of irrigated pasture. 3. Pastures are deeper rooted and soils more permeable than local mythology presumes. 4. Waterlogging is a major consequence of inefficient surface irrigated pasture. 5. Less frequent irrigations and shorter durations will reduce water logging and give greater pasture productivity

Knowledge management, sensing and control tools for irrigated broadacre cropping

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