Effects of Trunk Shaker Duration and Repetitions on Removal Efficiency for the Harvesting of Oil Olives

Trunk shakers are primarily used for the mechanical harvesting of olives for oil in traditional orchards. At present, these machines cannot be adjusted according to the maturation conditions of the fruit throughout the harvest season. For this reason, it is common practice to lengthen the shaking times and repeat the shaking process in an attempt to remove the greatest amount of fruit. However, these practices may reduce the useful life of the equipment and increase the risk of damage to the tree trunk. This study considers three periods during the harvesting season, as well as the application of one continuous vibration or two, short-duration, consecutive vibrations. The measurement of fruit maturity and an analysis of the images of the removal process showed the importance of shaking time and the number of vibration repetitions on fruit removal. During the initial and middle periods of the harvesting season, the use of two consecutive vibrations (10+10 s) removed more fruit than one continuous vibration (20 s). Nevertheless, repeating the vibrations during the end harvesting period was not effective in increasing the removal efficiency. At the start of the harvesting season, an average shaking time of 13.3 s was needed to achieve removal of 90% of the fruit susceptible to collection by shaking. This time decreased by 2.1 s at the end of the harvesting season.