Objective  To explore the influences of hole size of the nest hole wheel seed-metering and the adaptability of Panax notoginseng seeds on seed-filling performance, determine the relationships between P. notoginseng seeds of different grades and the adaptability shapes of seed-metering devices.

Method  We divided P. notoginsengseeds into four levels, and designed four different types of nest hole sizes. Using the discrete element software EDEM, we simulated the seed-filling process of graded seeds in seed-metering device with different size of nest hole. The seed filling performances of different grade seeds in seed-metering devices with different sizes were analysed, and the adaptability size of seed-metering device for the graded seeds was obtained. The experimental verification was carried out.

Result  P. notoginseng seeds of all levels have their suitable nest hole wheels. The 5.0−5.5 and 6.5−70 mm grading sections of seeds have the suitable hole sizes of 7.5 and 8.5 mm respectively, and both of 5.5−6.0 and 6.0−6.5 mm grading sections seeds match the hole size of 8.0 mm. When seeds of all gardes are filled in the adaptive seed-metering devices, the qualified indexes are more than 95.83%, the miss-seeding indexes are lower than 2.00% and the redundant-seeding indexes are 2.17%. The linear relationship between the long axis size of seed (l) and aperture (L), and the relationship between the height axis size of seed (h) and hole depth (H) are all established, which areL=0.58l+4.28and H=0.75h+3.96, respectively.

Conclusion  The seed-filling performance fully meets the agronomic requirements ofP. notoginseng seeding, which provides a theoretical basis for the design of nest hole size of the nest hole wheel seeding device.