Precision farming, based on satellite technology, could see returns to WA graingrowers jump $20-30 per hectare.

A review of these technologies, funded by growers and the Federal Government through the Grains Research and Development Corporation (GRDC), revealed WA growers could now use global positioning systems (GPS) for reliable yield mapping.

Yield mapping helps growers identify productive cropping areas by plotting grain yield against field position, which can assist decisions on fertiliser and spray applications.

With WA growers, on average, applying 43 kg/ha of fertilisers and spending $40/ha on spray, the more strategically they could manage these inputs the better, according to Hyden farmer and GRDC Western Regional Panel Chairman, Dale Baker.

“Using GPS they could make more accurate diagnosis of limitations to crop growth, or retire unproductive areas from the rotation."

“It could also assist with field trials, allowing TOPCROP groups, for example, to gauge various strategies by comparing inputs and yields,” he said.

Yield mapping had been limited, in WA, by the cost of complex receivers able to compensate for an inaccurate GPS signal.

A free correction signal, broadcast by the Australian Maritime Safety Authority, could only be received in some coastal regions, with costly equipment and a substantial annual fee required to get a correction signal across most of WA, according to GRDC project supervisor, John Billingsley, National Centre for Engineering in Agriculture.

“But, in May last year, then US President, Bill Clinton, announced the lifting of selective availability, a constraint used to obscure global positioning systems so terrorists couldn’t use them to guide weapons.

“This has increased the accuracy of GPS ten fold, making it a viable option for growers across the state, because now a simple low cost receiver could be used at a cost of well under $1000,” said Professor Billingsley.

The GRDC project also investigated more complex GPS systems, using satellite signals to manage autonomous and robotic machinery.

According to Professor Billingsley, trials using low cost components and a local base station, achieved 2cm accuracy, which was good enough for this purpose.

“The next challenge is to provide accurate, reliable systems for operating robotic machinery at a cost far below today’s, allowing complete integration of GPS into all aspects of agricultural production,” he said.