Bridging manual labour and mechanisation: Enhancing blueberry harvesting efficiency for New Zealand’s fresh market

Abstract

This thesis addresses the challenges of fresh market blueberry harvesting in New Zealand, where rising global demand and labour shortages put pressure on traditional handharvesting methods. Although hand-picking remains the industry norm, it is labourintensive and costly. With global blueberry consumption projected to grow, developing efficient and sustainable harvesting methods is critical, particularly for local growers. The core objective of this research was to develop a human-assisted mechanical harvesting system tailored for tunnel-grown fresh market blueberries. This system utilises lightweight, battery-powered handheld reciprocating shakers and multi-level soft surface catchers designed to reduce harvest damage, minimise ground loss, and improve fruit quality and yield. Performance assessments compared this system to traditional hand harvesting regarding post-harvest quality and harvest rate in field trials across two seasons. The field trials yielded valuable findings. In Field Trial 1.0, the Catcher V1.0 showed promising results, achieving a harvest efficiency of up to 83.7%, slightly less than the 89.3% efficiency of hand-harvesting into buckets. In Field Trial 2.0, the optimised Shaker V2.0 had a harvest rate of 81.3 berries/min, outperforming traditional hand-harvesting into a bucket (71.8 berries/min) and hand-harvesting into Catcher V3.0 (80.3 berries/min). Notably, Catcher V3.0 caused the least berry damage (0.9%), confirming the benefits of its soft surface design. For the Masena cultivar, optimal shaker settings were identified at 899 RPM and a shaking duration of 1.08 seconds, achieving a projected harvest performance score of 81.76%, with detachment accuracy of 93.21% and detachment efficiency of 96.53%. Future research should focus on larger-scale trials, long-term economic analysis, and developing methods to assess bloom retention. The integration of machine vision could further enhance this system, enabling fully automated harvesting, even during nighttime operations. These innovations have the potential to improve efficiency and sustainability for New Zealand’s blueberry industry.