# Applications of Water Jet Cutting Technology in Agricultural Engineering: A Review
## 4 Conclusions and Recommendations  
As a non-contact and cold processing method, water jet cutting technology can cut various agricultural materials without heat generation, sharpening and cleaning blades, and cross-contamination. Nowadays, relevant reviews have been carried out on six agricultural materials (i.e., vegetables, fruits, meats, woods, stems, and soils) for completing different cutting operations, improving cutting ability, or controlling post-cutting influences. To achieve specific purposes and products, water jet cutting technology is used for harvesting, slicing, peeling, trimming, and injecting. Adjusting the water jet cutting parameters and jet media properly can deepen the cutting depth, decrease the kerf width, or reduce the surface roughness, so as to obtain a better cutting ability. Similarly, some phenomena and questions after cutting, including brownish cut edges of vegetables, microbial counts, and the loss of raw materials, are controlled by adjusting relevant parameters. Moreover, the research focus of water jet cutting of each material in agricultural engineering is different. Specifically, cutting parameters are optimized by cutting experiments to control the browning of vegetable cuts for good quality. Meanwhile, harmless disin-fectants can be mixed into the working fluid of liquid jet cutting to prevent the bacterial infection of vegetables. When harvesting vegetables or fruits in the field, it is necessary to keep them clean. To improve work efficiency, the post-harvest processing of fruits adopts water jet technology equipped with intelligent control methods. Adding abrasives or liquids to working fluids can cut bone and larger sections of meat and reducing meat loss (or kerf width) needs AWJ cutting or pre-cooling. As for wood cutting, abrasives are required for better surface qualities of a smaller surface roughness value and kerf width. Cutting stems and soils needs mobile machines working in the field. Besides, anti-blocking and jet weeding require that stems are cut off, and the cutting depth of soil is vital to jet fertilization. Therefore, water jet cutting technology has become an important approach to cutting agricultural materials. However, the research on water jet technology is still in its infancy with high costs and needs further development of deepening mechanism research, optimizing agricultural machinery, and adopting intelligent control. First, simulate jet generation processes, cutting processes, and microscopic damages under different parameters to deepen the research on the cutting mechanism of agricultural materials. Meanwhile, the optimal cutting parameters of simulation experiments can provide a reference for practical operations and reduce research and development costs. Second, optimize agricultural machinery to reduce water consumption and jet pressure. Recycling water from horizontal jet harvesting machines allows for smaller volume tanks. Adding abrasives achieves the same cutting effect under low pressure, but further research is needed for additional effects on the field environments. Third, adopt intelligent control methods to improve work efficiency and reduce labor costs. Some technologies (i.e., machine vision, image processing, robotics, sensors, etc.) should combine with water jet cutting technology to realize real-time monitoring of cutting effects and automatic adjustment of cutting parameters. **Author Contributions:** Conceptualization, D.C. and H.L. ; writing--original draft preparation, D.C.; writing--review and editing, J.H., Q.W., C.L., H.H., X.C. and C.W. ; funding acquisition, H.L. All authors have read and agreed to the published version of the manuscript. **Funding:** This research was funded by China Agriculture Research System of MOF and MARA (Grant No. CARS-03); Chinese Universities Scientific Fund (Grant No. 2021 TC011). **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** Not applicable.