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Wireless networks have yet to become commonplace for growers but research into the technology has given two Canadian growers a glimpse of the technology’s potential.

Brothers Rod and Don King own and operate King Family Vineyards, a 42-acre property just north of Penticton, British Columbia, that supplies grapes to the Sandhill Wines division of Andrés Wines Ltd.

Three years ago, the Kings participated in a research project that saw 60 to 80 battery-powered microcomputers, known as motes, placed in a three-acre block of the King family’s vineyards. The block, shaped somewhat like a bowl, was a challenge with regard to frost control.

“We’ve always had a lot of fun with this particular site in terms of frost control with regard to how high up the basin the frost line is,” Rod King said.

The Kings originally planted Pinot Auxerrois, a late-budding, early maturing variety they hoped would avoid frost.

“It has worked relatively well,” Rod King said. “But having said that, if we got a late frost in the spring, then we have been having to run overhead irrigation for frost control. But that had its limitations because we only had so much water available from the irrigation district. So, it was always very frustrating in the sense that you’re limited by your water supply.”

When Intel Corporation approached Dr. Pat Bowen of the Pacific Agri-Food Research Centre in Summerland, British Columbia, regarding a trial of wireless sensor networks in an agricultural setting, Bowen immediately thought of the Kings.

Bowen knew the peculiarities of the Kings’ situation through her work with GIS (geographic information systems) mapping the Okanagan’s vineyards. For the Kings, the chance of understanding that particular area of their vineyard a bit better was an incentive.

“It was not an inconvenience for us in the slightest, and it might help us get a better grasp of the frost situation,” Rod said.

Intel researchers at the University of California, Berkeley, programmed the motes to collect information on vineyard conditions and relay it by wireless network to their office.

Rather than having to go out in the middle of the night to check temperatures and turn on the irrigation equipment, the Kings were able to get temperature information sent to their house. Temperatures that placed the vines at risk from frost damage triggered an alarm.

The convenience of not having to check vineyards in the dead of night was just the first benefit, Rod said.

Combined with a contour map of the vineyard, information from the motes pinpointed variations in temperature that both confirmed their suspicions about what was happening in the vineyard and uncovered new information.

For example, while the motes recorded variations in temperature of as much as 33 percent within the vineyard, researchers were surprised to find that hot air moved around during the day rather than pooling. By contrast, cool air flows at night were more stable with temperature variations showing a more consistent pattern of occurrence.

“It was a very positive experience in helping us define what was going on,” Rod said. “Based on the knowledge that we gathered in the basin where the Auxerrois was, we have been able to fine-tune the area where we’re using our frost control.”

The results haven’t had a huge impact on the farm’s profitability, but Rod said research over the long term could help define climatic zones in the vineyard and facilitate more plantings to match conditions. This would help the vineyard be more efficient and productive.

“It would be very interesting to have ten years of data over the entire vineyard on a very small scale, where, as we replant we could fine-tune those boundaries even better,” Rod said.

Imagination

Given the data-gathering power of the sensors, Rod King believes imagination is the only limit to the potential of the motes to aid vineyard managers.

“It’s conceivable that these motes could talk to a sensor or a computer on a sprayer,” Rod said. “These things could be tracking humidity, rainfall, etc., etc., and you could just drive along with the sprayer and it could spray only according to the specific microclimate.”

Similarly, the motes could help to improve water management by triggering irrigation on an as-needed basis.

A significant barrier to the motes’ use is price. The sensors used in the Intel trial produced by San Jose, California-based Crossbow Technology, Inc., retail for close to $150 a piece. At 20 to 30 motes an acre for a basic network, the cost quickly rises.

Bowen looks forward to testing a cheaper model of Crossbow’s mote, due out this year, but she is also engaged in research with sensors from a Kelowna company that retail for about $50 apiece. They’re not wireless, but the cheaper cost is attractive.

Growers looking for a system they can deploy with relative ease will be hard-pressed, however. Though the technology is attractive, it hasn’t yet reached the point where it’s widely available.

“The potential is there but I think there needs to be more off-the-shelf stuff for people to use,” Bowen said.