Hot air balloons drifting in multicolored splashes against a blue heaven are a common sight in the Napa Valley. But lately, more than balloons have been taking to the wine country skies.
A few pioneers are experimenting with unmanned aerial vehicles, better known as drones, exploring their potential for such agricultural chores as monitoring, irrigation and crop spraying.
Drones make sense for wine country, especially on the steep slopes associated with high-end wines, says Steve Markofski, spokesman for Yamaha Motor Corp. USA, which has been testing its RMAX remote-controlled helicopter for spray applications with the University of California, Davis.
Tractors may be defeated by the narrow rows and hilly terrain, but a drone can skim over the rows no problem. They also don't tamp down on the earth like tractor tires, a problem that can starve roots of oxygen among other things.
Once strictly a military machine, drones have been slowly moving into civilian life. Civil rights groups have raised concerns over possible invasions of privacy, especially in the context of law enforcement use, but the Napa Valley test flights, limited to private property, didn't encounter opposition.
Yamaha, which has used its RMAX drones for agriculture spraying in Japan for over 15 years, isn't the only company interested in viticulture. A Canadian company, PrecisionHawk, has modified a drone to resemble a hawk, initially using it to scare away grape-eating birds from vineyards in the Niagara wine region. They later realized they also could collect useful data on things like insect populations and diseased vines during the flights.
The RMAX is 9 feet long, weighs 220 pounds and runs on a two-cylinder engine. It's navigated by a radio controller much like a large-scale hobby helicopter and has an on-board GPS system to assist in flight accuracy. It even sports an attitude control system to compensate for wind and keep the aircraft stable. The RMAX also is fitted with two tanks and three spray nozzles for applying pesticides and nutrients.
Economically, the RMAX compares well with trying to get a tractor up hills or resorting to workers carrying backpack sprayers. Drones also could make it easier to deal with problems affecting only a portion of a vineyard, says Markofski. When a problem is detected, it would be easier and faster to deploy a drone to spot treat the problem areas instead of having to treat the entire vineyard with a tractor, he says.
The RMAX also goes about 10 times faster than a tractor, even though it's flying quite slowly at 12 mph while spraying.
But before the concept of vineyard drones takes off, grape growers will have to be won over.
"It's going to take time," Markofski acknowledges.
Daniel Bosch, viticulture manager at Robert Mondavi Winery, where some of the Yamaha-UC David aeronautical research was carried out, is interested in the potential of drones, though he's far from swept off his feet.
Using the drone to fly along vineyard rows to get an idea of different levels of ripeness didn't save that much time since it took a while to watch the videos, he said. Using the drone to go up in the air and take a panoramic shot worked better. On the other hand, there's potential to use drones to map vineyard temperatures more accurately than airplanes, since it can fly close to the vine canopy.
The most interesting use to Bosch would be if the entire process could be automated, such as drones programmed to fly, complete a task, then return with the information.
Markofski doesn't expect drones to replace tractors, but he thinks they will prove to be the better choice in certain situations.