Corn whole plastic film mulching on double ridges has been the main production mode of maize planting in arid regions of Northwest China in recent years. An effective technical way can be widely used to stabilize the corn yield. Among them, the vertical roller-type corn harvest header can greatly contribute to the simultaneous harvesting of corn ears and stalks. Specifically, the clamping and conveying device can effectively shorten the length of the harvest header. The vertical roller group can reduce the impact force between ears and picking rollers, even the picking loss. The stalks can also be cut in a centralized way. However, the current integrated device of clamping and conveying is often scratched on the surface of the plant stem by the sharp chain teeth, resulting in more broken stems on the harvest header. In this study, the clamping and conveying device was designed for the vertical roll-type header of the corn combine harvester, in order to achieve the smooth clamping and conveying of maize plants without damaging the stalks. The clamping and conveying channel were adaptively adjusted with the plant stem thickness, in order to improve the clamping stability with the low rate of broken stems in the clamping and conveying device of the vertical roll-type corn header. The device was composed of the reel chain and clamping and conveying mechanism. The reel chain mechanism was for the orderly feeding of individual maize plants, and the reciprocating cutter to complete the cutting of plant roots. The clamping and conveying mechanism was used to realize the effective clamping and conveying of cut plants on the vertical roll-type corn header. In addition, a fold line path of the clamping and conveying channel was formed under the joint action of large and small chain clamping pulleys, as well as the bilateral clamping and conveying chains. The clamping and conveying channel clearance was adjusted, when the stalk passed through the channel, according to the stalk diameter under the tensioning mechanism of the bilateral clamping and conveying chains. There was a more reasonable clamping force on the clamping and conveying mechanism, and a more reliable clamping and conveying, compared with the integral chain structure. An optimal combination was also achieved in the process of the toggle-feed in, grip-cutting, and grip-conveying, where the effective reel section chain length of the reel chain mechanism was 500 mm, the length of the clamping and conveying channel was 1 100 mm, the maximum clamping and conveying capacity of the harvest header was 3, and the vertical distance between the grip rails was 40 mm. Furthermore, the clamping and conveying channel between the two-reel chain was adjusted to 16～40 mm under the grip rail chain clamping pulley and the tension device. The response surface method (RSM) was used to analyze the effects of the forward speed of the harvest, the rotating speed of the drive sprocket, the angle of the harvest header, and the feeding angle of the plant on the operation performance of the clamping and conveying device. The test results showed that the total ear loss rate was 0.83%, and the broken stem rate was 0.12% when the forward speed of the harvest was 2.8 m/s, the rotating speed of the drive sprocket was 1 210 r/min, the angle of the harvest header was 18°, and the feeding angle of the plant was 60°. The total ear loss rate and the broken stem rate were reduced from 2.80% to 0.83% (30%), and from 0.98% to 0.12% (12%), respectively. This finding can provide the theoretical basis and technical reference for the high quality and low damage of vertical roll-type corn harvesting.

Potato planting area and the total output have been ranked first in the world in recent years. Since the potato can serve as a growth crop under the soil, the harvest process is complex, large labor intensity, time consuming, and high labor costs. Potato harvest mode is still dominated by manual and semi-mechanized harvesting. Mechanized harvest is one of the key links in potato mechanized production. The low rate of mechanization harvest has been the short board for the potato harvest equipment in the field of agricultural machinery at present. The current situation has restricted the development of the Chinese potato industry. This review aims to summarize the planting characteristics, distribution, and mechanized harvest status of potatoes in the main production areas. At the same time, the key technologies of potato mechanization harvest were also reviewed at home and abroad. For example, the potato efficient ridge-like vine killing, potato digging device, potato low-loss and high-efficiency separation, multi-functional walking chassis, as well as human-computer interaction. The potato digging device was elaborated in the drag reduction and soil breaking, bionic digging, vibration digging, anti-blocking and depth limiting, as well as automatic ridge finding technology. The key technologies of potato low loss and high-efficiency separation were described in detail, including potato soil separation, potato vine separation, potato stone separation, flexible protection, and low position container. A summary was also provided for the structure and technical characteristics of typically small and medium-sized potato diggers, potato picking machines, as well as small-, medium-, and large-sized combined harvesting machines. A systematic analysis was made of the potato mechanization harvest. 1) It was difficult to complete the matching of machines and tools, particularly in various planting modes, complex terrain, and wide planting areas in the small plots in the hilly and mountainous areas. 2) There was a large proportion of small-scale planting areas, the high cost of purchasing harvesting equipment, and the weak ability of farmers to resist risks, leading to insufficient purchasing power for harvesting equipment. 3) Some potatoes in vegetable harvest accounted for a large proportion of China, with high requirements on the quality of the mechanized harvest. Farmers shared low trust in the harvesting equipment, and most of them used manual harvesting. 4) There was no perfect leasing service system for agricultural machinery, resulting in the low utilization rate of mechanized harvesting equipment. 5) The low separation effect and high impurity rate were found in the domestic combined harvesting machinery under the condition of large damage and sticky heavy soil. 6) Much attention can be expected to pay agricultural machinery research and development and support. Therefore, the mechanized potato harvest can be the trend of joint development in the step and combined harvest. In addition, the future directions prospected for the low loss and high-efficiency separation device, the breakthroughs in the weak technology, deep integration of agricultural machinery and agronomy in the agricultural machinery service system, together with the national policy support. The finding can also provide a strong reference for the development and research of mechanized potato harvesting technology in China.

In view of the problems in operation process of fixed rake-type residual recycling component, such as poor individual profiling effect in film picking, easy clogging of the compound of films, soil and maize stubbles, high power consumption in film picking, and strong disturbance to seedbed soil, in this study, an operation model of intermittent film-picking on full-film mulched double ditches was proposed and an intermittent film picking component was designed. The DEM-MBD coupled algorithm was adopted for numerical simulation on the operation process of the intermittent film-picking component on full-film mulched double ditches, and a comparative analysis was carried out on the seedbed disturbance effect and resistance variation characteristics in film-picking by fixed and intermittent film-picking components. By taking the forward speed in film-picking, cam arrangement angle of the film-picking component and rotating speed of the cam shaft as independent variables, film-picking rate as the response value, a mathematical model between test factors and the film-picking rate was established, to explore the influence order of the factors on film-picking rate, and the optimal working parameters of the intermittent film-picking component were obtained as follows: the forward speed in film-picking was 2 km/h, cam arrangement angle was 180°, rotating speed of the cam shaft was 120 r/min. Under the optimal parameter combination, the average film-picking rate of the simulation test was 96.1%. Field test showed that, the average film-picking rate of the intermittent film-picking component was 95.6%, and 0.5% higher than that of the simulation test. The working condition of the sample machine was basically consistent with the simulation process, and can accurately represent the operation mechanism of intermittent film-picking on full-film mulched double ditches, showing that the established discrete element simulation model and its parameters were accurate and reasonable.

Flax has been one of the most essential oilseed and cash crops in the northern and northwestern hilly regions of China. Flax stems are fiber-abundant and have high nutritional value in their seeds. Mechanical harvesting of flax can rely primarily on segmented picking with combined harvesting at present. However, the entanglement of flax stem during harvesting has emerged as a significant bottleneck, severely impacting harvesting efficiency and industrial development. The power and space layout of a combined harvester are limited in the hilly areas, due to the high cellulose content of flax stems, strong toughness, intertwining capsules, and fruits during maturity. The stems can be easily entangled in the conveyor churn during harvesting. Low mobility cannot fully meet the large-scale production in recent years. This study aims to investigate the influence of the key components of the header in the common grain combine harvester (T₁ model) on the motion attitude of the flax plant. A discrete element flexible model of the flax plant was constructed using MBD-DEM co-simulation technology. A systematic analysis was also made to clarify the tangling mechanism of the header in the common combine harvester. An anti-entanglement plate device was proposed to solve the tangling of the header in order. The key components of the header (T₂ model) were optimized to determine the motion behavior of the flax plant. The anti-entanglement mechanism of the flax header was also clarified after optimization. Finally, a field test was carried out for the verification. The simulation results indicate that there was a greater variation in the average X-axis velocity of the flax plant before 0.6 s, compared with the T₁ model only. Once the flax segments entered into the high-speed movement, the average X-axis velocity minimally changed on the different segments until 0.6 to 0.85 s. The flax segments were turned into a relatively stable movement after 0.85 s. At the same time, the plants accumulated at the spiral blade, accompanied by their rotational motion and the propulsion provided by the spiral blade, leading to the entanglement of the flax stem. Before 0.45 s, minimal variation was observed in the Z-axis velocity of the flax plant segments in the T₁ model. But after that, these velocities tended to change significantly within a narrow range. Specifically, the X-axis velocity of the flax plant segments was accelerated in the T₂ model from 0.64 to 0.77 s. While the flax segments experienced high-speed movement from 0.77 to 1.5 s. An anti-entanglement plate was added to the header to significantly adjust the X-axis velocity. There was a minimal variation in the Z-axis velocity of the flax plant segments in the T₂model before 0.55 s. But after that, these velocities tended to change significantly. Field verification demonstrates that the T₁ model shared a total loss rate of 3.32%, an impurity rate of 3.57%, four instances of winding, and an efficiency of 0.14 hm²/h; The T₂ model presented a total loss rate of 2.29%, an impurity rate of 3.39%, no instances of winding, and an efficiency of 0.23 hm²/h, indicating a 39.13% improvement in the operational efficiency over the T₁ model. The operational performance of the T₂ model fully met the requirement of the flax harvesting. The finding can also provide valuable insights for the design and testing of flax combine harvesters.

The application of plastic mulch in the arid regions of northwest China has demonstrated significant advantages, making roller-type hole sowing on mulch a key agricultural trend. In order to enhance the performance of a roller-type corn finger planter equipped with finger pickups. This study analyzed the motion patterns of corn seeds within the device and investigated the effects of control cam parameters, including pickup section, vibration section, pickup stroke angle, and torsion spring force, on seed-metering performance. Using DEM-MBD coupling technology, single-factor experiments and second-order orthogonal rotational combination simulation experiments were conducted. The optimal parameter is that pickup section stroke angle is 78.98°, vibration section stroke angle is 20.07°, and a normal force is 2.99 N, which was validated through bench tests, achieving a seed-metering qualification rate of 93.86%, a missed seeding rate of 3.19%, and a reseeding rate of 2.95%. These results met the standards and agronomic requirements, demonstrating the effectiveness of the proposed optimization method. It provides a foundation for improving the precision and reliability of roller-type corn seed-metering devices.