Innovative progress in the mechanical harvest of California table olives

The Issue

The economic sustainability and consequent longevity of California’s historic black ripe table olive industry is challenged by the cost of hand-harvest, which is often 50 to 75 percent of gross return. Hand-harvest costs are volatile due to dynamics in annual and regional crop load and labor supply, and are influenced by competition between growers and producers of other commodities. Reliance on hand-harvest in concert with weather-related crop failures has led to Tulare County olive acreage shrinking by 20 percent over the past decade. Multi-generational families of olive growers either left agriculture or diversified to other crops, forcing processors to import olives, often of a lower quality, to maintain inventory. Development of a mechanical harvesting method offers hope for long-term industry sustainability.

What Has ANR Done?

The California Olive Committee funded efforts between UC researchers and University of Cordoba, Spain researchers and industry stakeholders to develop mechanical harvesters. Karen Klonsky, UCCE specialist in the Department of Agricultural and Resource Economics at UC Davis, estimates that 80 percent fruit removal is necessary for economic feasibility of mechanical harvest. In 2006, Louise Ferguson, UCCE specialist in the Department of Plant Sciences at UC Davis, formed a team of engineers, horticulturists and farm advisors to develop and test mechanical harvesters. A trunk shaker, originally used for pistachio, and a prototype canopy-contact harvester, developed for jatropha, have been modified for use on olive. Trunk shaker technology may be more applicable to olive trees with a smooth trunk, upright growth habit, and short scaffolds, whereas canopy-contact harvesters may be better suited for hedgerow plantings managed with mechanical pruning. The research team found that the mechanical harvesters achieved near 80 percent fruit removal efficiency, and panels of sensory and consumer analysts are unable to detect a difference between mechanically harvested and hand-harvested olives.

The Payoff

Mechanical trunk shaker implemented in 2012 harvest.

UC research showed trunk shaking technology is feasible for table olive harvest and inspired fabricators to continue improving upon the technology. The trunk shaking technology was first implemented commercially in the 2012 season in Sacramento Valley table olives.

Clientele Testimonial

“If it had not been for the specific commitment of Dr. Louise Ferguson to mechanical harvesting and the olive industry, we would still be stuck with technology and viewpoints from the 1950s and 60s and would therefore be no closer to solving what I believe to be the most significant issue we face as an industry,” said grower Dennis Burreson.


Supporting Unit: Agricultural & Resource Economics

UCCE, Plant Sciences, Agricultural and Resource Economics, Biological and Agricultural Engineering, Food Science and Technology
Elizabeth Fichtner, UC Cooperative Extension advisor, Tulare County,