Investigation of the effect of shaking amplitude and frequency levels on pistachio nut or cluster detachment.
2004
Loghavi, Mohammad | Taj Abadipoor, Ali | Rahimi, Hosien
The aim of the present research was to determine the most suitable shaking frequency and amplitude for pistachio nut or cluster detachment with imparting the lowest damage to branch or tree. A tractor mounted limb shaker was used to conduct the present study. The shaker was mounted on a tractor by tree point-hitch linkages and received its power from the tractor power- take-off shaft. The rotating power was transmitted to shaker flywheel through a V-belt drive system and a mechanical clutch, where it was converted to an oscillating motion by a slider-crank mechanism. The resulted motion was transmitted to tree limb through a telescoping boom and a special clamping device. A4 x 4 factorial experiment with a completely randomized desigh in three replications was used to investigate the effects of shaking amplitude and frequency levels on pistachio nut or cluster detachment of Ohadi and Kaleghoochi varieties. Four levels of shaking frequencies used for Ohadi variety were 5, 7.5, 10 and 12.5 Hz. and for Kaleghoochi variety were 7.5, 10, 12.5 and 15 Hz. Four levels of shaking amplitude used for Ohadi variety were 20, 40, 60 and 80 mm and for Kaleghoochi variety were 40, 60, 80 and 100 mm. Experiments were conducted in two different orchards in two different regions. Test on Ohadi variety was conducted in the first year in Kerman and test on Kaleghoochi variety was conducted in the second year in Sirjan. Analysis of variance and mean comparison by Duncan’s multiple range tests showed that the effects of shaking amplitude and frequency on nut and cluster detachment in Ohadi and Kaleghoochi varieties were significant. It was found that in Ohadi variety, at 12.5 Hz frequency and 60-mm amplitude, the most effective nut detachment with minimum damage occurred. Also at 12.5 Hz frequency and 80 mm amplitude, the highest percent of cluster detachment with the lowest damage occurred and in Kaleghoochi variety, at 15 Hz frequency and 60 mm amplitude. Highest percent of nut detachment was obtained and at 80 mm amplitude and 15 Hz frequency, highest cluster removal was observed. The average F ratio (the ratio of statical tensile force required for removing nut to its weight) and average V ratio (the ratio of vertical statical force required for removing cluster to its weight) were determined as 1.8 and 19.6 for Ohadi variety and 2.94 and 22.7 for Kaleghoochi variety, respectively. Finally, The results of this study indicated that vibratory harvesting could be efficiently used in Iranian pistachio orchard. Key Words: Shaking amplitude, Frequency levels, Cluster detachment, Pistachio harvesting, Nut detachment.
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