The long-edge characteristics of narrow elongated suction holes in air suction seed metering devices guide the alignment of multiple seeds during multiple-seed adsorption. This feature offers advantages in applications requiring seed singulation. However, research on the application of narrow elongated suction holes in air suction seed metering devices is still limited. To explore the applicability of such suction holes in seeding operations, we conducted single-factor experiments and Box–Behnken experiments. The single-factor experiments, based on computational fluid dynamics (CFD) simulations, analyzed the effects of suction hole width, length, vacuum pressure, and particle diameter on the suction force acting on a single spherical particle as it moved from the suction hole center to the outer region near the seed metering disk wall. Additionally, the Box–Behnken experiments were conducted using a dynamic–static combined adsorption measurement test platform, establishing a regression equation with suction hole width, particle diameter, and vacuum pressure as the experimental factors and the critical suction hole length for dual-particle adsorption as the response variable. The single-factor experiments indicated that suction hole width, length, vacuum pressure, and particle diameter significantly influenced the near-wall adsorption capacity of the suction hole. Analysis of the dual-particle adsorption experiments revealed that when the narrow elongated suction hole was in a vertical position, the lower particle in the adsorbed pair was more likely to detach. The critical adsorption characteristics of the narrow elongated suction hole enable dual-particle deduplication while ensuring continuous single-particle capture, thereby facilitating precision seeding.

An understanding of the biomechanical properties of radish petioles is critical for the rational design of harvesting machinery and the optimization of the harvesting process. At present, research on the biomechanical properties of radish petioles is relatively scarce, and there is a lack of bonding parameters for the discrete element simulation model of radish petioles. To address these challenges, this study explores the impact of varying petiole parts, moisture content, and tissue structure on their mechanical properties through histological analysis and torsional testing. Subsequently, a discrete element simulation model for radish petioles, suitable for mechanized harvesting processes, was developed based on the BondingV2 model. The model’s bonding parameters were optimized through Plackett-Burman and central composite experiments. The experimental results indicate that the torsional modulus of the radish petiole is significantly influenced by moisture content and tissue structure, with the highest torsional modulus observed at the petiole’s distal end, exhibiting optimal mechanical performance at intermediate moisture levels. The petiole’s distal end exhibited the following properties: unit area normal stiffness coefficient is 2×10⁹ N/m², unit area shear stiffness coefficient (3.12×10⁹ N/m²), normal strength (1.5×10¹¹ Pa), shear strength (7.5×10¹⁰ Pa), and Bonded Disk Scale (1.17). The simulation results of axial tension, torsional bending, three-point bending, and field tests exhibited errors of 4.46%, 8.8%, 0.41%, and 2.1%, respectively, when compared to the corresponding physical test results, thereby validating the reliability of the bonding parameters calibrated for the distal petiole of radish at the optimal moisture content. The findings of this study provide a theoretical foundation and technical support for the optimization of mechanized harvesting equipment for radishes.

The adsorption performance of maize seeds in air-suction seed metering devices directly affects the operational quality of maize seeders. The suction holes on the seed metering disc play a crucial role in determining the device’s ability to adsorb maize seeds and serve as a key design parameter for air-suction seed metering systems. Existing research has primarily focused on seed posture control and suction force models for standard particles, while experimental studies on the actual adsorption performance of maize seeds remain scarce. To further investigate the adsorption characteristics of maize seeds under different suction hole geometries, this study employed a self-developed adsorption force measurement platform to conduct experiments on maize seeds in various adsorption postures. The resulting force–displacement curves reveal the variation of adsorption force as seeds detach from the suction holes. To assess the applicability of conventional suction force calculation models, computational fluid dynamics (CFD) simulations were performed to analyze the adsorption mechanism of standard particles. The simulation results indicate significant limitations in commonly used suction force estimation methods. For instance, in experiments evaluating the effect of equivalent adsorption area, the relative error between the suction force estimated by the traditional pressure-based method for triangular holes and the actual measured force reached 40.82%. Similarly, the relative error between the force estimated by the airflow drag method for square suction holes and the actual measured force under the same conditions was 17.14%. Therefore, when evaluating actual seed adsorption, it is essential to comprehensively consider factors such as suction hole geometry, blocked suction area, seed shape, vacuum pressure, and the overlap depth between the seed boundary and the suction hole, all of which significantly influence the adsorption effect.

This study addresses the agricultural requirement for flexible adjustment of planting spacing in seed breeding corn, designing an active rotating in-film hole-forming mechanism driven by an independent motor. The mechanism allows flexible regulation of planting spacing by adjusting the motor speed. The study first optimized the structure of the hole-forming device, selecting a rhombic duckbill as its core component and analyzing its motion trajectory and hole-forming shape. Single-factor experiments were conducted to determine the structural parameter ranges affecting film hole length. Using discrete element and multibody dynamics co-simulation, experiments were carried out with duckbill number, duckbill bottom width, and duckbill bottom height as experimental factors, and film hole length as the response variable, employing a three-factor, three-level orthogonal experimental method. Simulation results indicated that the factors influencing film hole length, in descending order of impact, were duckbill number, duckbill bottom height, and duckbill bottom width. The optimized best structural parameters were: 9 duckbills, bottom height of 351 mm, and bottom width of 22 mm, ensuring film hole length control within the range of 25–40 mm, meeting planting requirements, preventing weed growth, and ensuring a seed growth environment. Furrow testing validated the adaptability and planting performance of the mechanism under different spacing conditions, providing a theoretical basis and practical reference for the promotion of small-scale breeding and the sowing technology on the film for field seed production.