Krueger, William H

Ferguson, Louise

Cutter, Stan :

Isern, Antonio :

Establishing and Training Manzanillo Table Olives For Mechanical Harvest William H . Krueger , Louise Ferguson , Stan Cutter and Antonio Isern University of California Cooperative Extension Table olives in California are hand harvested . The cost of hand harvest can be as much as 50 percent of the gross . From 1997 to 2000 , the California Olive Committee ( COC ) , the table olive marketing order , sponsored the development of a mechanical harvester for table olives . Prototype machines were developed which had vibrating rods which engaged the tree canopy , resulting in a canopy shake . Although these machines looked promising , they had two major drawbacks : 1 . ) Efficiency of harvest - when the picking head came into close proximity of the fruit , it was removed . However , leading and trailing canopy edges and inside fruit proved to be problematic because it was difficult to get the head close to fruit located in these positions . Fruit removal was often disappointing . 2 . ) Fruit damage - The fruit can be damaged in the removal process . While this damage may appear similar to what may occur with hand harvest , the bruises are generally deeper and more severe . One of the major table olive processors quit accepting mechanically harvested fruit due to concerns related to fruit damage . This temporarily stopped progress toward mechanical harvest with this machinery . A continued and increasing need for mechanical harvest has rekindled interest . The COC resumed funding for mechanical harvest research in 2006 and expanded that support in 2007 . The focus of the research has been on improvement of the previously developed machinery to increase removal and reduce damage and the development of loosening agents to facilitate mechanical harvest . If a tree canopy could be developed in which all of the fruit was accessible to the picking head , a much improved harvest efficiency with reduced force and , therefore , reduced fruit damage should be attainable . The ideal tree and orchard configuration would appear to be a close spaced hedgerow system which would present a flat fruiting wall to the harvester with no leading or trailing edge and no inside fruit . A thin fruiting canopy approximately 6 feet in width and approximately 12 to 15 feet high would be appear to be ideal for maximum machine efficiency . With a narrow tree canopy and tree height such as this , narrower row spacing will be necessary to achieve maximum yields . This type of tree architecture should also be more adaptable to other types of mechanical harvesters including existing trunk type shakers and other types of machinery which could be developed . Objectives : The objectives of this work are to : 1 . ) Develop a narrow canopy hedgerow to facilitate mechanical harvest . 2 . ) Evaluate and demonstrate the feasibility of a high density hedgerow developed specifically for mechanical harvest . 3 . ) Compare different training methods for developing a narrow canopy hedgerow . Methods : In the spring of 2000 , Manzanillo variety table olives were planted on 2 acres at the Nickelâ??s Estate in Arbuckle with a north - south row orientation and a tree spacing of 12 feet in the row and 18 feet between rows ( 202 trees per acre ) . The selected training treatments included â?? conventional â?쳌 and three Espalier treatments . The conventional training consists of thinning out fruit wood and opening up the center of the tree . The trees will eventually have 3 to 5 primary scaffolds . With the Espalier treatments , permanent limbs are being trained parallel to the row in a narrow plane with flexible temporary fruiting wood extending approximately three feet out into the row on either side . Large stiff limbs extending into the tree row are positioned into the permanent limb plane or are removed . The Espalier treatments are : Free Standing - where pruning alone is used to conform the trees to the system , trellised woven - where potentially permanent limbs are woven between three wires spaced at 4 , 7 and 10 feet and trellised tied - where potentially permanent limbs are tied to the wires . The treatments are arranged in a randomized complete block design and consist of blocks of three rows of either seven or eight trees . There are four replications of each treatment . Harvest data is being collected from the center row of each treatment . The olives were harvested , weighed and 10 to 12 lb . samples were submitted to Musco Olives for commercial grading . The sample results were used to assign a value to the production . Originally 6 trees of the Sevillano variety were strategically placed in the planting to provide for cross pollination for the partially self incompatible Manzanillo . Due to disappointing growth of these trees , cross pollination was inadequate . Even though there was a good bloom , the fruit set for 2003 was disappointing and did not warrant harvest . During the summer of 2003 , the center row of the planting was top worked to Sevillano to provide for adequate cross pollination . During bloom in the spring of 2004 and 2005 , the block was artificially cross - pollinated using Sevillano pollen . The grafted pollinators developed well and artificial pollinization was discontinued in 2006 . In the spring of 2007 , about two weeks after full bloom , all of the plots were chemically thinned with Napthalene Acetic Acid ( NAA ) . Because the crop appeared light at pruning time in May , the tied Espalier treatment was not pruned . Results : Yields for 2007 were very good and ranged from 6.07 tons per acre for the woven Espalier to 7.51 for the tied Espalier with no statistically significant differences between treatments . Value per ton for the tied Espalier was significantly less than the other two treatments ( Table1 ) . There were no significant differences in value per acre . Through the seventh year , the cumulative yields are very similar for all of the treatments . Table 1 . Nickel's Hedgerow Olive Harvest , 2004 - 07 Treatment 2004 2005 2006 2007 Cum . Yield Tons / A Tons / A Tons / A Tons / A $ / Ton $ / Acre Tons / A Conventional 4.09 1.75 2.81 6.39 $ 1,037 A $ 6,600 15.04 Free Standing Espalier 3.66 1.51 2.26 6.40 $ 1,037 A $ 6,636 13.81 Espalier , Trellised , Woven 4.21 1.68 2.28 6.07 $ 1,011 A $ 6,153 14.24 Espalier , Trellised , Tied 3.58 3.45 1.76 7.51 $ 868 B $ 6,438 16.30 NS NS NS NS NS Numbers followed by different letters are significantly different at the 5 % level using Fischer's test . Discussion : Unlike the previous year , there was no correlation between proximity to the pollinizer row and yield , indicating that pollination ( a combination of self and cross ) was adequate in 2007 . Fruit values were not different for any of the treatments which were pruned in 2007 . The higher yield and smaller value per ton ( fruit size ) for the tied Espalier was , almost certainly , due to this treatment not being pruned in 2007 . Cumulative yields for all treatments are very similar through the first seven years and would be considered good for this area . To date the results indicate that olives trees can be grown and maintained in a narrow canopy hedgerow configuration with no reduction in yield or fruit value . A comprehensive project aimed at developing mechanical harvest for table olives is currently underway . This project is being headed by Louise Ferguson , UCCE Olive Specialist , and includes collaboration with a University of Florida researcher , UC Davis Department of Agricultural Engineering and Plant Sciences , UCCE Farm Advisors , California State University researchers at Fresno and Chico , farmers and equipment manufacturers and mechanical harvesters . Research is being conducted in the southern producing region ( San Joaquin Valley ) and the northern producing region ( Sacramento Valley ) . The planting at Nickels is playing an increasingly important role in this effort . Because we collect our yield data from only the center row of the three row plots , we have been able to use the other trees for other things to support this effort . These have included following changes in fruit retention forces from mid season through harvest , testing fruit loosening agents to facilitate harvest and antioxidant treatments to reduce fruit damage . A field meeting was held in October at the end of the table olive harvest season to show the planting and to demonstrate 3 different types of trunk shake harvesters . The meeting was attended by about 40 interested growers and industry personnel . As the effort to develop mechanical harvest for table olives continues , the planting at the Nickels Estate is positioned to play a critical role . Because it is an established planting it will continue to offer opportunities for research in support of the mechanical harvest project . We will be able to test new developments in machinery as it becomes available . We will continue to follow the development and production of the established treatments .