Olive picker, Olive harvester -tractor mounted pneumatic and hydraulic shaker, vibrator

Picking olives in California is usually done by hand or with vibrating rakes. More extensive machine picking will probably be common soon. Expect 3 tons per acre yield from mature trees or 80 pounds per tree. For hobby farmers get your friends to do it in return for some free olive oil or pay farm labor. A good laborer can harvest 200 - 500 pounds of olives a day depending on variety, terrain, tree size, etc. Expect harvest to account for 45-65% of the total production cost for olives or $200 to $300 per ton. Machine picking requires forethought as the trees must be the right variety, must be planted with proper spacing and must be pruned appropriately.

Korvan harvester

Sacramento: U.C. extension specialist Louise Ferguson moderated an excellent morning session at the California League of Food Processors Expo February 5th 2002. Below are synopses of two presentations.

Testing of mechanical harvesters

She started out the session with her field test of the Korvan 5000, Agrite and Olipicker olive harvesters. Again, many of the assumptions were oriented toward �black ripe� canning olives, Manzanillo being the dominant variety. Louise and U.C. have been involved for years with this project. Picking labor has been increasingly expensive and difficult to obtain and is the largest cost growers face. The Agrite is a self propelled picker while the Olipicker is a tractor mounted articulated arm with oscillating head similar to the Olivary. Much of her subsequent remarks centered around the Korvan, a self-propelled platform with multiple rotating heads with long plastic fingers and a catch frame and conveyor system. It takes one operator driving, keeping the catch frame skirts in contact with the trunk and another operating the rotating picking heads on swing arms. The machine moves at 1/2 MPH and can pick a tree in about 60 seconds. This works out to harvesting .4 acre per hour. Machine operators are paid $13/hr and a helper is around $9/hr. Korvan cost is around $200K. The machine is being sold as cost effective for olive orchards of greater than 180 acres.

Mechanical picking involves several different operations. The first is fruit removal. The Korvan removed 66% of the fruit in the trials. The fruit that was removed tended to be more mature and larger. Canners want minimal bruising during this step and the Korvan is fairly kind to the olive. A spokesman for Bell Carter, one of the largest canners in California, reported that last year mechanically harvested olives brought in to their inspection station 5 hours after harvesting had a damage rate of 35%. 2/3 of damaged olives were only minimally damaged, 1/3 had moderate to severe bruising or cuts. (Hand harvested fruit has a much lower damage rate). This could be minimized by brining the olives in the field but cannery representatives in the audience noted that doing so would prohibitively double transportation costs.

The second step is catching the olive. Earlier versions of the Korvan had problems catching the olives but the manufacturer reported that now only about 10% or less miss the catch frame and are lost to the ground. This could be minimized by buying left and right hand versions of the machine to run in tandem down the rows or by pulling a catch frame with a tractor on the other side of the tree.

The olives must then be collected and conveyed to a cleaner, in this case a powerful fan, and dumped into orchard boxes. The Korvan will be built to order this year. It is anticipated that contract pickers will buy the machine as is done in the almond, walnut and grape businesses.

Economic Model of Mechanical Harvesting

Karen Klonsky then took the results of the field test and extrapolated an economic model for mechanical harvesting. Contract harvesting was priced at $250/acre plus $150/ton. Other assumptions: Because the mechanical harvester preferentially removes riper, larger olives, culls would be 2.3% with the harvester, 3.7% with hand picking. The harvester would remove 66% of the olives, hand labor would remove 95%. Mechanical harvesting would be followed by hand harvesting to remove unpicked fruit. Price received would be $720/ton for mechanically harvested olives, $708 for hand picked olives. Hand harvesting would cost $260 per ton.

Karen concluded that mechanical harvest costs per ton were lower than hand harvest costs but removal rate is lower. At 3 tons of olive yield per acre the cost for mechanical and hand picking is about the same. With higher yield per acre the cost of mechanical picking would seem to decrease. Although close, at all yields per acre hand harvesting gave higher revenues per acre than mechanical harvesting. As efficiency of mechanical harvesting increases and cost of hand harvesting increases, mechanical harvesting will become more attractive.

Although mechanical hedging and topping of olive trees gives the machine a nicer working surface, Louise Ferguson cautioned that in her experience it drastically decreased yields. More research must be done in optimizing existing trees for mechanical harvesting.