Table olive harvest befuddles machines

Tim Hearden/Capital Press University of California Cooperative Extension olive specialist Louise Ferguson (right) talks with UC-Davis Olive Center executive director Dan Flynn during a break in an olive seminar April 18 in Corning, Calif.

Methods improve but still fall short of growers' needs


Capital Press

CORNING, Calif. -- University of California researchers are still trying to perfect a way for table olive growers to use mechanical pruning and harvesting to shave costs.

However, finding an efficient way to get the olives from the trees to bins unblemished is still a challenge, said Louise Ferguson, an olive specialist for the University of California Cooperative Extension.

Mechanical harvests have long been seen as a ray of hope for California's struggling table olive industry, as hiring hand labor represents as much as half a grower's annual cost, Ferguson said.

But the trunk shakers and canopy harvesters the university has been using have only achieved an efficiency rate of between 64 and 68 percent, she said. A grower would need to capture at least 80 percent by machine for it to be economically viable, she said.

However, researchers continue to collect data on different tree-training methods and different harvesting machinery, and Ferguson believes they have made great progress.

"After six years and about $1 million support from the California Olive Committee, we think we have things pretty well under control," she told about 100 growers during a workshop here April 18. "Most of you should start lowering your trees ... and I think you should start experimenting with mechanical harvests."

Lance Taylor, who grows table olives in Willows, Calif., is eager to start using the new technology. But not quite yet.

"I don't think they've got the efficiency down yet," Taylor said. "It seems like they've got everything else down, but getting it off the tree is the biggest thing."

Mechanical harvesters have been used successfully by the olive oil industry, for which fruit damage is not an issue. The table olive industry has been trying for more than a decade to develop a similar method, first investing $3 million between 1997 and 2001 to develop a machine that ultimately caused too much fruit damage to be viable.

In 2006, the industry again began funding mechanical harvesting development, as new plantings in narrow canopy hedgerow systems are better suited for both canopy shaking and trunk shaking. UC-Davis experts have estimated that hand-picking costs about $400 per ton, or about $2,000 an acre with a yield of 5 tons per acre, compared to about $400 an acre for mechanical harvests.

Since then, the researchers have been tinkering with the method, including the strength at which the trees can be shaken to remove fruit without damaging the tree. They found padding for the trunk clamps to avoid damage that could kill the tree, and a canopy contact harvester caused less than 1 percent major damage to branches, Ferguson said.

Taste tests have shown that most consumers can't tell a difference between handpicked and mechanically harvested table olives. In University of California trials, trained sensory panels and random consumers could easily differentiate between fresh and stored olives, but they couldn't distinguish between olives picked by a contact canopy head and those picked by hand when it came to aroma, appearance and taste, Ferguson said.


University of California-Davis Olive Center:

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