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UBC Theses and Dissertations

A study of mechanization alternatives in fruit harvesting Yomchinda, Vitawas


Fruit-growers in the lower mainland of British Columbia are facing a potential labor shortage for hand harvesting of fruit. Prices paid to hand picking labor have increased by more than 100 percent in the last three years. These factors have prompted interest in mechanical harvesting methods. The purpose of this research was to investigate the feasibility of introducing mechanical harvesting methods in raspberry production and to determine optimum machine parameters. A review of methods used for determining the optimum size of agricultural equipment was conducted and the methods were summarized. Due to the nature of small fruit production some commonly used methods were not applicable and modifications were necessary. A fruit yield function and a timeliness function were developed for Willamette raspberries. The fruit yield function based on actual yield data, was used for determining the potential income from a raspberry plantation. The timeliness function, based on the reduction of fruit quality due to variations in the length of the interval between subsequent harvests, was used to determine a suitable charge for untimeliness at any part of the harvest season. An optimum fruit removal efficiency for mechanical harvesting of Willamette raspberries was determined by assessing the loss in potential income due to the removal of green fruit and the production of over mature fruit. This was based on published results of mechanical harvesting trials. Results indicated that the mechanical harvesting of raspberries could be potentially much more profitable than hand harvesting. A machine with a fruit removal efficiency of 80 percent and with an operating speed of 1.5 miles per hour, or greater, appeared to be optimum. At operating speeds above 1.5 miles per hour, the cost of mechanical harvesting was not significantly influenced by the purchase price of the harvester. The cost of untimely operation was large. Extending the interval between subsequent harvests by one day resulted in an annual profit reduction of approximately 200 dollars per acre.

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