Authors

Abstract

To meet the agronomic requirements for multiple-seed-per-hill sowing of millet, broomcorn millet, and rapeseed under plastic-film mulching in Northwest China, an air-suction precision seed metering device was designed and evaluated through theoretical analysis and bench testing. The device integrates seed agitation, suction, staged cleaning, conveying, unloading, and placement, and is equipped with ten hill-forming units with a hill spacing of 16 cm. The airflow field and seed motion during operation were theoretically analyzed, and seed trajectories were captured using a 300 fps high-speed imaging system at an operating speed of 3 km/h. By adjusting the inlet negative pressure and suction-hole diameter, the preliminary stable operating ranges were determined. The results showed that the observed processes of seed agitation, adsorption, cleaning, unloading, and detachment were consistent with the proposed seed-motion model. The stable negative-pressure ranges were 0.61–3.54 kPa for millet, 0.83–4.15 kPa for broomcorn millet, and 0.74–3.59 kPa for rapeseed, while the corresponding suction-hole diameter ranges were 0.6–1.2 mm, 0.8–1.4 mm, and 0.7–1.2 mm, respectively. In 1000-hill bench tests, the qualified rates reached 90.6%, 92.7%, and 91.6% for millet, broomcorn millet, and rapeseed, respectively. These results demonstrate the feasibility of the proposed device and provide a basis for further optimization and field validation.

Abstract in Chinese

为满足中国西北地区谷子、糜子和油菜籽覆膜播种条件下一穴多粒播种的农艺要求，设计了一种气吸式精密排种器，通过理论分析并用台架试验对其进行了验证。该装置集搅种、吸种、清种、运种、卸种和投种于一体，周向布置10个成穴单元，穴距为16 cm。对其作业过程中的气场分布和种子运动进行了理论分析，并利用300 fps高速摄像系统在3km/h作业速度下对种子运动轨迹进行了观测。通过调节吸气口负压和吸孔直径，确定了排种器的初步稳定作业参数范围。结果表明，观测到的搅种、吸附、清种、卸种和脱离过程与所建立的种子运动分析结果基本一致。谷子、糜子和油菜籽对应的稳定负压范围分别为0.61–3.54 kPa、0.83–4.15 kPa和0.74–3.59 kPa，相应的吸孔直径范围分别为0.6–1.2 mm、0.8–1.4 mm和0.7–1.2 mm。在1000穴台架试验中，谷子、糜子和油菜籽的合格率分别达到90.6%、92.7%和91.6%。结果表明，该排种器具有良好的应用可行性，并可为后续优化设计和田间试验提供依据。