Sunshine helps apples ripen and brings on their classic red color, but sun and heat can quickly become too much of a good thing apples can indeed get sunburn. Researchers at Washington State University are testing a high-tech approach to prevent the burn and save water and energy.
While apple tree leaves can soak up sunshine, fruit doesn’t dissipate heat as well. Sunburn can happen in as little as 10 minutes and unaddressed, sunburn can ruin as much as half of growers’ crops.
“Sunburn management is a major issue for apple growers, and it’s getting worse because of higher summer temperatures,” said Lav Khot, associate professor and precision agriculture scientist.
Most Northwest apple growers use overhead sprinklers to cool orchard canopies on hot days. But trees soak up that extra water and use it to grow shoots and leaves, changing their internal chemistry.
“That means less nutrients for the fruit, so disorders come through again,” Khot said. “It costs a lot of water, a lot of energy, and affects fruit quality and food safety—bacteria can breed in wet canopies.”
In a project jointly funded by the U.S. Department of Agriculture’s National Institute of Food and Agriculture and the National Science Foundation, Khot’s team is developing a sensor-based orchard system that can sense fruit surface temperature and fine-tune delivery of cool water for evaporative cooling.
News.wsu.edu reports how using infrared cameras and miniaturized weather stations, the prototype activates overhead sprinklers just when they’re needed, minimizing the negatives of spray cooling.
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