Australia: irrigators sense it's time to ignore clock

The wireless sensor device looks like a toy and is not much bigger than a person's hand — yet it heralds a revolution that could save massive amounts of water and help keep the state's agriculture industry afloat. The device, called a "nictor", uses wireless sensor devices that have been developed in a laboratory at the University of Melbourne. The lab is part of the National ICT Australia group of research centres.

The wireless technology is at the heart of a system that gets water to the crop and farm on demand, not by a scheduled roster. The system uses water more efficiently than a conventional irrigation system and requires less water to be used. It's the result of research that has been driven by John Langford, director of the university's Melbourne Water Research Centre, and a team of specialists from various organisations.

He gave an overview of the project to the international land care conference in Melbourne organised by the Department of Sustainability and Environment. "We are outcome focused. It's all about surviving in a future of water shortage — it's the sensible thing to do," said Professor Langford, a former managing director of the Rural Water Corporation of Victoria, who has been spent most of his professional life in the water industry.

Despite the public emphasis on Melbourne's water use, the city only uses 8 per cent of Victoria's water. A total of 77 per cent is used by irrigation, with the remaining 15 per cent taken up by regional cities and regional industry. "The major challenge is to improve the economic output of irrigation — consume less water and improve the productivity and profit per megalitre of water," Professor Langford said.

The research so far has concentrated on the dairy, horticulture and viticulture sectors in northern Victoria. The Goulburn Valley, the state's food bowl, uses about 2500 gigalitres of water annually. "Savings of 10-20 per cent of water are not beyond the bounds of possibility. That's a modest estimate," Professor Langford said.

Another researcher, Gavin Thoms from National ICT Australia, was more upbeat. "We'd be disappointed if we could not do better," Dr Thoms said. Professor Langford said dairying in northern Victoria was a particular focus, as the industry there used surface irrigation. "There is much potential to improve," he said. "In horticulture, a pink lady crop may now get 50 per cent of decent apples and the rest used for apple juice. If we can get the 50 per cent to 70 per cent, we will help the profitability of the enterprise."

The key is the wireless sensor technology. Each nictor is wired to five sensors — they can be soil moisture sensors, or air temperature or leaf sensors — and the wireless technology passes the information to a laptop computer. The sensor measures the soil moisture and activates the drip irrigation system; the water comes on when the soil moisture gets too low.

"It keeps the soil moisture within set limits and turns off again when the required amount of water has been added," Professor Langford said. "If a plant needs water, it calls for water, and the right amount is supplied." The nictor creates a closed loop system. "It's a self-healing network. If a cow steps on one sensor, the network is not destroyed, but will re-form," Dr Thoms said.

"The base station — the laptop — records all the information. The message always gets out. There's no need for Telstra!" Professor Langford said in an orchard, for example, the nictors needed to be within 200 metres of one another, which can extend to one kilometre if the nictors are in clear line of sight.

"They can be placed to meet the needs for sensing and control, and do not need to be in a regular pattern," he said. One member of the research team, Nicola Cooley, said the sensor was wired into the nictor similar to a traditional data logger. "But the difference is, with a logger you have to physically go out and collect the information, or you rely on a radio network to radio back the info," said Dr Cooley, a research fellow at Melbourne University's Dookie campus at Shepparton.

"There are cases of that being reliable and other cases where it is not as reliable, but it is improving. "But with the nictor, you have the added advantage that, because of the way the signals are sent, you can send more signals on a more continuous basis. The way the signals are sent, there is more reliability on the messages getting back to the computer or controller."

The three-year, $4.2 million research program is being conducted by the Melbourne Water Research Centre, NICTA, Goulburn Murray Water, and Melbourne University's engineering, as well as land and food departments. The State Government contributed $1.5 million.

The project co-ordinates a variety of skills: wireless networks, hydrology, irrigation, viticulture, horticulture, pasture agronomy, economic modelling, and control software. Professor Langford said successful field trials had been held. Pilot trials would be held in the second year and demonstration trials in the third year. "We are aiming for a cheap, plug-and-play model. It's easier to use, and no professional help is required to set up the network," he said.

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