Abstract
Mechanical harvest is one promising method to mitigate the labor pressure in fresh-market tree fruit industries. Due to the difficulty in adopting fully mechanical harvesting technologies in most of the current existing canopy architectures, this study aimed to evaluate the feasibility of a mechanical-assist shake-and-catch system to harvest sweet cherries in a large range of commercial orchards. Field evaluation was conducted on four cherry varieties from nine orchards with three canopy architectures. Time distribution in each procedure, and the harvest rate defined as the amount of fruit harvested by a shake-and-catch team (two operators) or a skilled picker in a minute, were analyzed to determine the key factors in efficient harvesting. Time distribution study showed that shaking time accounted for less than 30% of entire operation time, while more than 50% of time was spent on relocation of the shake-and-catch system. Results showed that cherry trees with small pedicel fruit retention force, small canopy size and heavy fruit load had higher harvest rate for mechanical harvesting. The harvest rate could be potentially increased as high as 13.9 times if only the shaking time was considered, which indicated the substantial influence of the processes of catching fruit, relocating fruit catcher and moving ladders. The test results also indicated that the tree architecture had substantial influence on fruit removal efficiency, fruit catching rate, and fruit damage rate.
