Existing plot seeders have several problems, e.g., seeding uniformity is poor, the breakage rate is higher, and so on. The design of a cone-grid format seed-metering device can both meet the experimental area's seeding-operation requirements and the plant-to-row seeding requirements. We clarified the overall structure, working principle, and technical parameters of a novel seed-metering device. The gap-adjustment range of the seed-distributing mechanism was determined by analyzing the force on buckwheat seeds. A kinematic simulation using Simulink clarified that the seed-metering control mechanism is capable of realizing precise seed-discharge control. In this experiment, we used the layout of seed gaps, seed displacement, and the rotation rate as influencing factors, respectively. We determined the sowing uniformity coefficient of variation and the broken rate as indicators of the orthogonal experiment. The test results were then subjected to modeling analysis and optimization using Design-Expert12 software to determine the optimal operating parameters. Subsequently, validation experiments were conducted. The results show that the optimal configuration of parameters consisted of a layout seed gap of 13.42 mm, a seed displacement of 17.67 g, and a rotation rate of 15.59 min-1. Under these optimal conditions, the coefficient of variation for sowing uniformity was measured at 14.56%, while the broken rate was 0.39%. The test results meet the technical requirements of buckwheat seed experimental-area sowing and plant-to-row sowing; for further research on buckwheat experimental-area breeding, this study provides a reference.
