Abstract:
China has been known as the largest producer of forest and fruit in the world, the same as grain and vegetables. The forestry and fruit industry can gradually dominate the ecological and economic benefits for better living. Therefore, a timely, non-destructive and efficient harvesting of mature fruits has greatly contributed to the subsequent fruit storage, transportation, processing, and sales. Mechanical harvesting has also been one of the most promising operations in the whole process of fruit production. More importantly, fruit mechanical harvesting has been one of the important ways for the forest fruit industry to transform the development mode for cost saving, high efficiency, and competitiveness in the international market. An automatic, intelligent, and unmanned harvesting of forest fruits can be preferred for the better performance of mechanical fruit harvesting, together with the high efficiency and low-loss picking in technical focus. In this review, the research progress was summarized on the mechanical harvesting of forest fruits in recent years, in terms of fruit planting and distribution in China. The planting forms mainly included the small step, steep slope, traditional, gentle slope, high ridge, and wide row dense planting. The reasons were clarified for the bottleneck of mechanical harvesting in the development of the forest fruit industry. The mechanical harvesting of forest fruit was systematically divided into one-time combined fruit picking, and fruit picking after vibration harvesting. Among them, the one-time combined fruit picking was divided into the pneumatic vibration, mechanical vibration (i.e. shaking, and impact type), orchard picking platform, and robot picking, according to the different operation modes of the picking parts. By contrast, the fruit picking after vibration harvesting was divided into the mechanical and pneumatic types, according to the different picking power modes. Then, the research status and development trends were elaborated to combine with the development requirements and application scenarios of the forest fruit industry. Four challenges were reviewed for the mechanical harvesting of forest fruit in China, including the complex working environment, the low level of appropriate mechanization, the limited basic research, and the lacking of Research and Development (R&D) talents. Accordingly, some recommendations were proposed for the mechanized harvesting of forest fruit. National support and R&D investment were the first concern to strengthen the cooperation between agricultural machinery and agronomy, thus promoting the mechanization level of the forest fruit industry. A production-university-research technical personnel training system was highly required to conquer the state-of-the-art technologies in the facilities and equipment during harvesting. It is very necessary to promote the deep integration of agricultural machinery and agronomy under the mode of mechanical harvesting of fruits and vegetables. The main focus can be made to explore the new technical mode with the planting agronomy for the mechanical harvesting of fruits and vegetables. Various agricultural requirements can be comprehensively considered to evaluate the reasonable technical system for better mechanical fruit harvesting with high performance, efficiency, and reliability. In a word, the mechanized operation of forest fruit can be widely expected to serve as the most effective way for cost saving, low labor intensity, but high efficiency during.