EFFECT OF CULTIVAR AND VIBRATION CHARACTERISTICS ON MECHANICAL HARVESTING OF OLIVES

To increase the yield of mechanical harvesting of olives, a counter-rotating trunk shaker (Model "Sgrullino" CIDIBI - Foligno) was used. Two methods of vibration, multidirectional and orbital and their combinations, were tested using two different frequencies (21 Hz an 27 Hz). In this way, greater variability of vibration was obtained in an attempt to affect the part of the crown otherwise not influenced by the action of the shaker. The trial was carried out on medium-sized plants of the cultivars ‘Ascolana tenera’, ‘Santa Caterina’, ‘Itrana’ and ‘Moraiolo’, characterized, respectively by the following detachment force/fruit weight ratios: 127.7, 182.9, 496.3, and 498.2. The use of different frequencies of vibration caused no significant differences in yield. There were no significant differences between the two single modules of vibration. They both gave yields of about 95% of the total production for ‘Ascolana tenera’, 80% for 'Santa Caterina' and 75% for 'Itrana' and 'Moraiolo' with small-sized fruits. Instead using the two modules in sequence, regardless of order, yield increases of 3–4% for ‘Ascolana tenera’, 15% for ‘Santa Caterina’, 11% for ‘Itrana’ and 10% for ‘Moraiolo’ were obtained. The combined system gave a consistent increase in yield, halving the quantity of olives left on the tree with use of the single modules.