Potato combine harvesters often face the challenge of balancing efficient potato–soil separation with minimizing tuber mechanical damage, which significantly affects harvest quality and economic returns. To address this issue, a dual-vibration potato–soil separation conveyor was designed based on agronomic planting parameters and soil physical characteristics. A high-fidelity DEM-MBD coupling simulation model was developed to analyze soil clod breakage behavior and potato collision-induced jumping dynamics, and to identify key operational factors influencing separation performance. The porosity was verified using computer vision combined with CT technology to ensure the model’s fidelity. Single-factor simulations and a central composite design (CCD) response surface experiment were conducted using potato damage rate and soil removal efficiency as evaluation indices. The results showed that the inclination angle α, conveying line speed V_f, and vibration frequency f were the dominant factors affecting separation efficiency and tuber integrity. Multi-objective optimization determined optimal operating parameters of α = 18.51°, V_f = 1.995 km·h⁻¹, and f = 6.22 Hz, under which soil removal efficiency reached 98.43% and the minimum damage rate was 1.60%. Field experiments using a 4U-1000 combine harvester verified the simulation results, with an average soil removal efficiency of 97.8% and an average damage rate of 1.62%. These findings confirm the accuracy of the DEM-MBD simulation model and provide theoretical guidance for optimizing separation devices in large-scale potato harvesting equipment.

Taro (Colocasia esculenta) stems are promising bio-based feedstocks for composite materials, textile fibres and adsorbents; however, a quantitative understanding of how their microstructure governs mechanical behaviour remains lacking, constraining their application. This study conducted mechanical tests and scanning electron microscopy (SEM) tests on stems harvested from different ground elevations. The results show that axial tensile strength (σ_t) and nominal radial compressive stress (σ_c) increase first and then decrease with height above ground. σ_t (2.67 MPa) and σ_c (7.64 MPa) both peak at 50–100 mm above ground level. Furthermore, the ultimate nominal compressive strength (σ_c) is significantly higher than the ultimate tensile strength (σ_t) at all heights above ground. Correlation analysis revealed that cross-sectional area A_c (r = 0.83), fibre bundle area fraction P_c (r = 0.78) and fibre wall thickness T_c (r = 0.77) were significantly positively correlated with σ_t, while A_c (r = 0.62) and T_c (r = 0.70) were positively correlated with σ_c. The tensile and compressive properties are closely associated with three microstructural parameters: cross-sectional area, fibre bundle area fraction, and fibre wall thickness—whereas fibre cell area shows only weak correlations with all mechanical indicators (r < 0.5) and is not a key regulatory factor. The stem cross-section transitions from crescent at the base to near-circular at the apex, with the reduction in bearing area underlying the decline in mechanical properties. These results offer a fundamental basis for tailoring mechanical preprocessing parameters and for selective utilisation of stem segments with distinct mechanical performance, thereby supporting the efficient conversion of this abundant biomass into value added materials.

To address seed contamination, narrow-row mechanized cutting difficulties, and potential damage to maternal plants in muddy paddy fields during hybrid rice seed production, a walk-behind self-propelled hybrid rice male parent pulverizing and cutting machine was designed. The machine primarily consists of three key structures: a key cutting device, a gravity-free crop dividing device, and a crawler walking mechanism. The cutting device features an innovative mechanism where main-shaft rotation drives flail blades into inertial autorotation, while a stopper bar physically constrains their maximum swing amplitude to guarantee a 500 mm working width. Crucially, the gravity-free crop dividing device safely pushes aside adjacent maternal plants to effectively prevent accidental mechanical injury. A flexible plant model and a kinematic model were established using DEM software EDEM 2024. A three-factor, three-level orthogonal experiment indicated that the primary order of influence on the male parent cutting rate is forward speed > flail-blade rotational speed > blade arrangement. The optimal simulation parameters were a 0.4 m/s forward speed, a 1700 r/min blade rotational speed, and a straight–curved blade arrangement, yielding a simulated cutting rate of 97.60%. Furthermore, field tests demonstrated that under these optimal parameters, influenced by complex paddy conditions and natural plant lodging, the actual average cutting rate was 91.39%. The machine exhibited excellent passability and pulverizing performance, thoroughly satisfying the requirements of agronomic and agricultural machinery integration.

To address seed contamination, narrow-row mechanized cutting difficulties, and potential damage to maternal plants in muddy paddy fields during hybrid rice seed production, a walk-behind self-propelled hybrid rice male parent pulverizing and cutting machine was designed. The machine primarily consists of three key structures: a key cutting device, a gravity-free crop dividing device, and a crawler walking mechanism. The cutting device features an innovative mechanism where main-shaft rotation drives flail blades into inertial autorotation, while a stopper bar physically constrains their maximum swing amplitude to guarantee a 500 mm working width. Crucially, the gravity-free crop dividing device safely pushes aside adjacent maternal plants to effectively prevent accidental mechanical injury. A flexible plant model and a kinematic model were established using DEM software EDEM. A three-factor, three-level orthogonal experiment indicated the primary order of influence on the male parent cutting rate is: forward speed > flail blade rotational speed > blade arrangement. The optimal simulation parameters were a 0.4 m/s forward speed, a 1700 r/min blade rotational speed, and a straight-curved blade arrangement, yielding a simulated cutting rate of 97.60%. Furthermore, field tests demonstrated that under these optimal parameters, influenced by complex paddy conditions and natural plant lodging, the actual average cutting rate was 91.39%. The machine exhibited excellent passability and pulverizing performance, thoroughly satisfying the requirements of agronomic and agricultural machinery integration.