PARLIER, Calif. — As labor shortages intensify, growers in California are switching to shorter peach and nectarine trees to eliminate the need for ladders.
University of California scientists have developed “semi-dwarfing” rootstocks in various densities to create “ladderless” orchards, enabling laborers to save time by picking from the ground rather than having to move and position ladders during harvest.
Growers have planted about 1,000 acres of the new rootstocks in the past three years, said Kevin Day, a UC Cooperative Extension farm adviser in Tulare County.
“They’re being planted by small growers and large growers,” Day said. “They just really like this concept.”
Day worked with UC-Davis plant physiology professor Ted DeJong on developing the rootstocks, using a four-acre plot at the Kearney Agricultural Research and Extension Center in Parlier. Their mission was to test whether shorter peach and nectarine trees could reduce labor and insurance costs without sacrificing fruit quality and yield.
Day said he’s seen labor cost savings of between 35 and 40 percent in tests of semi-dwarfing rootstocks so far. Moreover, the use of ladders in conventional orchards is why peach and nectarine growers pay about 40 percent more for workers’ compensation insurance than growers who work with shorter crops such as grapes, the UC has explained.
“Also, what people don’t realize is it takes skill to position a ladder,” Day said, noting a worker needs to be able to pick as much fruit as possible from one spot.
“From a sociological perspective, as labor becomes more scarce, we’re seeing more and more women in crews, and ladders are heavy,” he said. “Women can pick just as fast as men, but moving the ladder takes its toll.”
Conventional peach and nectarine trees grow to about 13 feet tall, requiring the ladders to harvest the fruit. Laborers spend about half their time setting up, climbing and moving the ladders.
Developed by breeders at UC-Davis, the new rootstocks produce trees that grow to 7 or 8 feet tall.
The trial at Kearney is part of a larger experiment on best practices for the fruit trees. The researchers have been comparing yields from a conventional orchard with those of shorter trees that have been minimally pruned, made use of pressure chambers to determine water needs and been treated with compost and nitrogen sprays to minimize nutrient leaching into groundwater.
The scientists found the shorter trees to be actually more productive, as their fruit quality overall is equivalent to that of the top half of larger trees, while lower fruit in conventional trees tends to be light-starved and of poorer quality, Day said.
Day expects more of the shorter trees to be put in as growers change out their orchards.
“Change takes time,” he said.