In order to investigate the mechanism of interaction between a vertical rotary tiller and the soil to obtain the best structural and operational parameters of the tool, improve the operational quality of the rotary tiller, achieve the effect of soil breaking and leveling to meet the agronomic requirements of tillage, a series of simulation tests was conducted through the design of 3D models of rotary tillers with different structural forms and the building of discrete element models of the action between the rotary tiller and the soil. The virtual simulation of different operating parameters and structural parameters of vertical rotary tiller was carried out by EDEM, and the effects of operating parameters, tool bending angle, and cutter installation number on the operating effect were analyzed. The parameter combination with the best operating effect was obtained through orthogonal test analysis and verified by soil trough test. A soil tank test showed that, with the optimal combination of operating and structural parameters, the average soil breaking rate of the vertical rotary tiller was 81.3%, which meets the agronomic requirements of tillage operation, and the actual power consumption was 6% higher than the simulation value, which was sufficiently close to verify the validity of the simulation. This study can lay a foundation for optimization research on the vertical miniature rotary tiller.

In view of the problems that the fuselage inclines and the driving straightness is difficult to guarantee due to the sinking and sliding of the wheels when the high-clearance plant protection machine is working in the paddy field, this paper takes high-clearance wheels as the research object, based on the paddy field driving environment, establishes a prediction model of the wheel subsidence through derivation, and explores the influence of different wheel parameters on the subsidence characteristics through experiments, so as to improve the chassis trafficability. At the same time, using the test data under different wheel parameters, the prediction model of the settlement of the working chassis with high clearance is correspondingly modified. Finally, the paddy field trafficability of the working chassis is compared and analyzed based on different tire parameters. The results show that when the wheel slip rate is 0.5, the traction force of the solid tire is 37% higher than that of the pneumatic tire; when the height of the wheel spike increases, the traction force increases, and the settlement decreases obviously; proper increase of the wheel diameter can improve the passing performance of the chassis; with the increase of the tire width, the angle of soil penetration decreases while the tire is driving, and the angle of the slope climbing increases; and when the load changes, the driving coefficient is proportional to the traction coefficient, and the tire resistance coefficient is inversely proportional to the traction coefficient. Through the research on the settlement mechanism of the high-clearance operation chassis and the analysis of the paddy field trafficability, the stability of the high-clearance plant protection machine in the paddy field has been improved, providing a platform and guarantee for subsequent precision operation.

This study aimed to design a counter-rotating dual-axis spiral ditcher to address the problems of the lack of ditching models, low ditching quality, and high power consumption in ditching operations in hilly and mountainous orchards. By establishing a discrete element simulation model of the interaction between the dual-spiral cutter and the soil, we analyzed the effects of different operating parameters on the ditching performance and power consumption to explore the mechanism of the interaction between the soil-engaging components and the soil; meanwhile, according to the simulation data, we took the forward speed, cutter speed, and ditching depth as the experimental influencing factors, and we took the ditching qualification rate and power consumption as the experimental indicators. Then, through a three-factor and three-level orthogonal experimental analysis, we obtained the optimal parameter combination. Based on the optimized simulation results, a prototype ditcher was fabricated, and the results of a soil trough test showed that the ditcher had a stable ditching performance, an average ditching qualification rate of 91.4%, an average soil crushing rate of 72%, and a ditching adjustment structure that could adjust the ditching depth and width within the ranges of 15–25 cm and 10–20 cm, respectively. The optimized ditcher had high efficiency, stability, and energy savings during its operation, and it was able to meet the agronomic requirements for ditching operations. This study provides a design basis and technical support for dual-spiral trial ditching operations.

Crop cultivation in solar greenhouses is affected by issues such as low levels of automation in spraying machinery, inefficient spraying, and a lack of suitable spraying equipment for vertically cultivated crops, all of which are in urgent need of resolution. To address these problems, this paper proposes a suspended-rail automatic variable-distance targeted spray system. The rated working speed of the spray system is 0.3 m/s, and the rated working pressure is 0.3 MPa. This system achieves precise spraying of crops at varying heights by dynamically adjusting the position of the spray nozzle. To ensure accuracy in spraying, the system employs a laser ranging sensor for real-time measurement of crop positions and spraying distances. Combined with a parameter processing scheme, the system generates control signals to adjust the operation of the electric push rod and electromagnetic valve, thereby dynamically adjusting the spraying distance and timing. Using vertically cultivated potted peppers as experimental subjects, this study compares the performance of fixed- and variable-distance spraying modes. The results indicate that, compared to the fixed-distance mode, the automatic variable-distance mode increases pesticide adherence by 16.65% and reduces pesticide usage by 29.58%. The proposed suspended-rail automatic variable-distance targeted spray system offers an effective technical solution for the precise spraying of vertically cultivated crops in solar greenhouses and thus contributes to improved pesticide utilization efficiency, reduced pesticide residue, and lower environmental pollution.

The input of exogenous organic matter could affect the transformation of soil carbon (C) and nitrogen (N), and their C- and N-priming effects (CPE and NPE) play a key role in the balance of soil C and N. However, little is known about how the interaction effect between straw and straw biochar regulates CPE and NPE. Therefore, we conducted a 90-day incubation experiment, which included five treatments: no straw and straw biochar (CK), 1.5% straw (S), 0.53% straw biochar (B), 1.5% straw + 0.53% straw biochar (SB), and 1.5% straw + 1.06% straw biochar (SB1). Our findings revealed that cumulative soil CO₂ emissions were increased by 95.52–216.53% through the short-term input of exogenous organic matter input; however, this trend gradually weakened with decreasing dissolved organic C (DOC) content. The cumulative NPE generated by the addition of exogenous organic matter was much smaller than the cumulative CPE. Under the B and S treatments, the cumulative CPE and NPE were negative throughout the entire incubation period. The SB treatment remarkably boosted the microbial biomass nitrogen (MBN) content; however, the SB1 treatment was more effective in inhibiting soil C and N mineralization processes than SB treatment. Moreover, the cumulative CPE and NPE were mainly regulated by N. We conclude that the combination of straw and straw biochar preferentially stimulated soil C mineralization, but that this effect decreased with time, which may be due to the consumption of labile DOC caused by the initial positive CPE, while soil N mineralization had a lag effect.

Today, the post-harvest root stubble treatment of kale in Hunan mostly uses manual pulling and centralized treatments, which are inefficient and labor-intensive. In this study, to realize the direct mechanical crushing of kale root stubble and return it to the field after harvesting, we established an accurate simulation model of kale root stubble by creating a model of the root stubble of kale and calibrating the parameters of the simulation. This study took Jingfeng No. 1 kale stubble as the research object and used EDEM2021.2 simulation software to study the parameters of the kale stubble-crushing simulation model. The peak shear force of the sheared kale root stubble was used as the test data, and the most significant factors affecting the shear force were screened out through the Plackett–Burman test for the Design-Expert design. In addition, the steepest climb test and Box–Behnken test were used to accurately assess the factor data to obtain the best simulation value, which was 861.02 N. The relative error between the simulated and measured values was 0.61%. Finally, an accurate simulation stubble model was established by combining the best simulation parameters with the measured stubble length and diameter. This model provides a theoretical basis and technical support for more in-depth research on stubble simulation and mechanized stubble return.