Key Technologies of Plug Tray Seedling Transplanters in Protected Agriculture: A Review

Abstract

The process of plug tray seedling transplanting is a crucial step in protected agriculture production. Due to issues such as high labor intensity, poor consistency of work quality, and low efficiency, the application of automated transplanting machines has provided a solution to these issues. For the diversity of transplanting operations, various mechanical structures and technological applications have been developed for automated transplanting equipment. Therefore, this paper provides systematic research of current studies on the key transplanter technologies. Firstly, through an analysis of the types of transplanting operations, the technical requirements of automated transplanting equipment for different operation types are elucidated. Subsequently, the key technologies applied in transplanting machines are discussed from the perspectives of substrate physical characteristics, end effectors, integration of multiple end effectors, vision systems, and transplanting path planning. Moreover, an analysis is conducted on the advantages, disadvantages, and application scenarios of different research methods for each key technology. Lastly, the existing problems and technical difficulties of the transplanting machine are summarized, and future research directions are discussed. This analysis provides a valuable reference for further research and development in the field of transplanting machines for plug tray seedlings.

Modeling the Mechanical Properties of Root–Substrate Interaction with a Transplanter Using Artificial Neural Networks

“…Currently, researchers focus on the following three aspects: (i) the characteristics of the substrate block itself, including compressive properties, creep properties, tensile properties, etc. [23]; (ii) the adhesiveness between the substrate and tray cell wall, such as the bonding force between the root system and pore wall and the influence of substrate moisture content on the success rate of seedling picking; and (iii) the interaction process between the substrate and the transplanting manipulator, involving factors such as the friction coefficient between the substrate and the seedling needle, and the broken pattern of the substrate caused by the steel needle [24]. These methods require the use of mechanical instruments and sensors, etc.…”

Research on a Vibrationally Tuned Directional Seed Supply Method Based on ADAMS-EDEM Coupling and the Optimization of System Parameters

“…Seedling transplanting is the main mode of the efficient cultivation of vegetable crops such as dried peppers and processed tomatoes. Compared to the live field model, it has the advantages of protection from natural disasters, high growth intensity, improved crop quality, and higher yields [1][2][3][4].…”

Design, Integration, and Experiment of Transplanting Robot for Early Plug Tray Seedling in a Plant Factory

“…However, the development of plant factories is constrained by drawbacks such as high energy consumption [9,10], high per-unit area costs [11], and limited space, which is not conducive to the installation of large-scale automated equipment [10]. Moreover, the suboptimal quality of the seeds, imprecise seeding within the plug trays, unfavorable temperature and humidity conditions, and insufficient nutritional provision, along with the presence of plant diseases and pests, collectively contribute to a suboptimal germination rate ranging between 80% and 95% [12,13] for seedlings cultivated in plug trays [14] and subsequently lead to yield losses in both the per-unit energy consumption and per-unit area. This, in turn, exacerbates the operational costs of plant factories.…”