What’s good for apples ought to be good for cherries.
So, Washington State University researchers are starting a cherry-specific Smart Orchard in the same vein as the apple version.
Smart orchards are commercial fruit blocks that welcome technology companies to test their equipment in real-life conditions and under scientific scrutiny. The Washington apple industry has hosted multiple smart orchard locations since 2020, in partnership with WSU and the Washington Tree Fruit Research Commission. (Blueberries have a couple in the Northwest, too.)
Backers said apples and cherries are different enough to warrant their own tech playgrounds.
“They’re different animals,” said Keith Oliver, manager of Olsen Bros. Ranches, home of the Black Pearl cherry block in Benton City selected for the project, in part because it’s an automation-friendly system featuring a V-trellis and upright fruiting offshoots, or UFO, training.
Oliver said the cherry growers’ goals for vigor, crop load and nutrition diverge from those for apples.
The three-year project will begin in earnest this fall, when a trio of WSU researchers begin receiving the $210,000 federal Specialty Crop Block Grant through the Washington State Department of Agriculture.
For now, graduate student Leslie Vite is getting things started in one row by comparing the data from an array of digital sensors to data gathered through more traditional means, such as physical soil core samples and a pressure chamber. Three days a week, she and intern Jose Pimentel measure fruit growth by dendrometers, photosynthesis by a leaf cuvette and stem water potential with an embedded microtensiometer from FloraPulse, among other sensors. Some of the equipment is not yet commercially available.
Vite considers her work the first steps in helping growers make more efficient use of resources, especially water. Raised in Central California, she has seen farmers go out of business because they didn’t have irrigation, either because of drought, access restrictions or both.
“I know rice growers that shut down operations altogether,” she said.
She recognizes that cherry growers face tough economic times, but she aims to help determine which tools they would find accessible and useful.
“Not all technology works for all a grower needs,” she said.
Big questions
Vite’s work will springboard the researchers into one of their main topics for the Smart Orchard — defining stress in cherries, said Matt Whiting, a WSU tree fruit physiologist. Sometimes data indicates trees should be stressed, but Oliver, the grower who knows the trees, thinks they’re fine.
“Ultimately, that’s the key question that has yet to be answered: What is stress?” said Whiting, the principal investigator on the project. “It is very complex.”
Once fully funded, researchers will use the Smart Orchard for studying water, heat and cold stress; testing overhead cooling; trying out different sensors; and creating a culture of unbiased testing, Whiting said. They’ll also trial optical sensors — from companies such as Vivid Machines, Orchard Robotics or Bloomfield Robotics — that help growers estimate crop volume by counting fruit. Several of those tools were developed in apples, but cherry tree leaves tend to shroud fruit ripening in clusters, making it harder to count.
“It’s really a different question and a really different challenge in cherries,” Whiting said.
None of those companies has signed up yet, but Whiting expects many to do so. He figures the university may have to turn away some firms.
Cherry growers need management tools for rain cracking, bird deterrence and different chemicals than those used for apples, said Bernardita Sallato, a WSU tree fruit extension specialist and a co-PI on the project. She hopes to use crop estimation tools to help manage soil, nutrition and irrigation to optimize fruit quality.
She singled out one sensor that uses a camera to track stem and fruit shrink, a potential way to study the relationship between water and fruit size.
Leaf clips measure relative humidity, temperature and transpiration in the cherry block. (Ross Courtney/Good Fruit Grower)
A dendrometer attached to an upright cherry branch reads daily fluctuation in diameter and overall growth over time. (Ross Courtney/Good Fruit Grower)
An array of plant and soil sensors undergird the cherry orchard canopy, including, from left, an explant tree tag, a 3-foot-deep soil sensor and a FloraPulse irrigation sensor under the foil wrap. (Ross Courtney/Good Fruit Grower)
Vite, left, checks the validity of high-tech sensors against the stem water potential reading from a traditional pressure chamber while Pimentel logs other data in the cherry block. (Ross Courtney/Good Fruit Grower)
The other co-PI on the project is Lav Khot, director of AgWeatherNet at WSU. All three are based at the Irrigated Agriculture Research and Extension Center in Prosser.
Sallato is excited to use drones to monitor cherry mildew and bacterial canker as well. Disease mapping by drone has worked for apple mildew.
Overall, she wants to ensure the tools deliver the useful data the suppliers promise, one of the same goals as the apple Smart Orchard.
“I continue to see myself as a ground truther, basically validating the outcomes at a biological and economical level,” Sallato said.
Oliver expects some of the gadgets that will be tested in the block will help his fellow growers, but he understands that most probably won’t. No one will know which is which until researchers evaluate them in a scientific way, he said.
“Let’s look,” he said. •
