Chemical control using pesticides remains an essential component of crop pest and disease management, while precision pesticide application is a core element for achieving sustainable agriculture. Precision spraying technology-integrating UAV-based detection, real-time pesticide mixing, and adaptive variable-rate spraying-provides a critical pathway for sustainable crop protection by establishing a "perception-decision-execution" closed-loop framework.While previous reviews have predominantly focused on compartmentalized analyses of individual technologies (e.g., sensing or actuation), this study establishes a unified Perception-Decision-Execution (PDE) framework to, for the first time, quantitatively assess the synergistic interactions and systemic Bottlenecks across all three layers.This paper systematically reviews 168 core publications from 2013 to 2024, proposing for the first time and quantitatively assessing the synergistic effects of technologies within this closed-loop framework. The findings reveal that: (1) UAV-deep learning systems achieve pest identification accuracy rates of 89-94%, but this significantly declines to 60-70% under strong light or occlusion conditions; (2) Real-time mixing systems attain a mixing homogeneity coefficient (γ) > 85% for liquid pesticides, while for suspension concentrates (SCs), γ decreases to 70-75% due to particle sedimentation effects; (3) PWM-based variable-rate spraying reduces pesticide usage by 30-50% and off-target drift by > 30%, though sensor errors can cause positioning deviations of 0.3-0.8 m. Despite considerable promise, this integrated technology faces challenges in large-scale applications, including perception degradation under environmental disturbances, limitations in algorithm generalization, poor pesticide formulation adaptability in mixing, and system coordination issues. To overcome these barriers, this review proposes interdisciplinary solutions: (i) Deploying lightweight edge devices and pruned neural networks to address decision-making delays and enhance real-time responsiveness; (ii) Optimizing mixer structures (e.g., helical baffle angles) based on computational fluid dynamics (CFD) simulations to reduce dead zones and improve mixing homogeneity for SCs; (iii) Integrating multi-sensor technology for drift compensation to enhance UAV spraying stability. By integrating and optimizing these key technologies, the closed-loop framework holds significant potential to markedly improve pesticide utilization efficiency, minimize environmental impact, and offer a practical framework for achieving on-demand application, thereby advancing sustainable smart agriculture.

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.