Wine is fine, but motes can make it better.
Intel Research and Agriculture and Agri-Food Canada – Canada's version of the U.S. Department of Agriculture – are using a wireless sensor network to measure air temperatures across a 50-acre vineyard in southern British Columbia.
Working on a hillside overlooking Lake Okanagan, the owners of King Family Farms will use the temperature sensors to help protect their crops from frost damage. After analyzing long-term data from the sensors, they'll also be able to harvest grapes more productively, and cut their use of pesticides and fungicides.
Each palm-size sensor, called a mote, consists of a sensor board, a radio processor and two AA batteries. Hanging from trellises as close as 20 feet apart, the motes form an efficient, low-power wireless network that connects to a PC in the vineyard manager's office.
Radio signals hop from one mote to the next until they reach the manager's PC. The software running on the network's open-source operating system, TinyOS, selects the best transmission routes for the motes to use.
"The shortest physical distances, or the fewest hops, don't always make the best paths," said Anind Dey, senior researcher at the Intel Research Lab at the University of California at Berkeley. "We've developed algorithms that instead determine which paths will have the least signal loss, for example."
Scientists at the UC Berkeley lab designed the motes, which are also being used at a vineyard in Dundee, Oregon, and a wildlife habitat on Great Duck Island, in Maine. Crossbow Technology out of San Jose, California, sells commercial versions of the same motes.
The temperature motes will help King Farms target specific plants for frost-control measures, such as misting the plants with water.
"Water here is a community resource that is becoming increasingly scarce," said Don King, who co-owns the vineyard with his brother, Rod. "The system will help us avoid overwatering."
The motes will also help King get a better night's rest. Until now, he's been fighting frost the old-fashioned way: by patrolling the vineyard at night with a lantern and a portable thermometer. "I used to grab a sleeping bag and sleep out in the cold spots with a thermometer and an alarm," he said. "It was really pretty primitive."
Even very small farms have numerous hot and cold spots, which require different amounts of water. "Cold air runs down a hillside like a river," said Pat Bowen, a plant pathologist for AAFC, Canada's agriculture department. Parts of a farm's topography can hold on to cold air longer than others, causing pockets of frost damage that affect vines' productivity for years.
But cold isn't always bad for grapes. Arctic blasts from the Canadian Northwest produce grapes with a sweeter, more concentrated juice, which winemakers use to produce icewine, one of King Family Farms' specialties.
Cumulative temperature data from the motes will tell King which plants will yield the best icewine. It will also help King choose the best moment to pick his grapes – a process known as precision harvesting. A plant's total number of high- and low-temperature days determines whether its fruit will make a better Pinot Noir, Chardonnay or other wine.
"At best, viticulturists have used average temperatures over broad areas to make that calculation," said Intel researcher Richard Beckwith. "This makes those numbers much more accurate."
The scientists at King Family Farms hope to add additional motes that measure light, humidity and other factors that affect plant growth and disease resistance.
AAFC's Pat Bowen wants to use the data to map the farm's tiny subclimates, called mesoclimates. The map will depict planting zones similar to those shown in seed catalogs, "but on a much smaller, and much more precise scale," Bowen said.
Don King, meanwhile, said he is excited about what the motes will tell him about his land. But he is still waiting for them to build software that allows him to view and crunch the data on his PC.
"Scientists are good at coming up (with) so much bloody data. Making it useful is going to be the hard part."
