Shake-and-Catch Harvesting for Fresh Market Apples in Trellis-Trained Trees

Abstract

Currently, fresh market apples are picked manually around the globe, which has become a challenge due to the decreasing availability of labor and the high associated cost. To reduce harvest cost and dependence on human labor, researchers and growers have been seeking mechanical solutions for decades. However, the high rate of harvest-induced fruit damage has been an obstacle to commercializing these technologies. To achieve a desirable level of fruit quality with mechanical harvesting, a new shake-and-catch system with two catching buffers for reducing fruit impact was developed and evaluated in this study. The system provides localized harvesting by shaking targeted tree limbs and catching the detached fruits directly under the limbs. To test the performance of the catching device, a series of laboratory tests was conducted using an impact recording device. The results showed that the impact force of falling fruit and the number of impacts decreased dramatically when using a catching surface with buffers compared to using a catching surface without buffers. A harvesting test was performed with ‘Jazz‘ apple trees trained to vertical fruiting wall architecture. The system achieved fruit removal efficiencies of 84%, 86%, and 92% for shaking frequencies of 15, 20, and 25 Hz, respectively. The corresponding collection efficiencies were 99%, 98%, and 93%. The system achieved the highest quality grade (Extra Fancy) for 85% of the harvested fruits when the limb was shaken at 15 Hz and fruits were collected using a catching surface tilted at an angle of 25°. With this level of performance of the prototype system, this study showed that the developed shake-and-catch system offers a promising solution for mechanical harvesting of ‘Jazz‘ apples, with potential extension to other apple varieties grown in modern fruiting wall architectures.