Abstract:

: The mechanized sowing operation of corn breeding can improve test accuracy and efficiency and speed up the test process. In view of the problems of low flexibility, high price, and poor sowing quality of the current seeder in corn breeding experiments, the critical components of a hand-pushing corn plot precision planter were optimized. Through the analysis of the relative motion between corn seed and the hole seed-metering wheel, the hole diameter range and hole depth range of the hole seed-metering wheel were determined as 13~19 mm and 6~12 mm, respectively. The chamber structure was optimized to improve the seed filling performance under the condition of a small number of seeds. The angle range between the connecting plate and the horizontal line (ACP) and the angle range between the back plate and the horizontal line (ABP) were 35~55° and 40~70°, respectively. EDEM was used to simulate the seeding circumstances of hole seed-metering wheel with different holes sizes. The optimal combination of hole diameter and depth under different seeds’ sizes and the appropriate angle combination of ACP and ABP were obtained through the orthogonal test. The results of the simulation experiment showed that the optimal hole diameter–depth combinations of the small, medium, and large corn seeds were 13–8, 15–10, and 17–8 mm, respectively. The angle ACP and the angle ABP were, respectively, 45°and 70°. The soil bin test was carried out to further verify the actual seeding effect and the influence of the rotating speed of hole seed-metering wheel on seeding. The results showed that when the rotating speed of hole seed-metering wheel was less than 16.0 r/min, the qualified seeding rates and the double seeds rates of the small, medium, and large corn seeds were higher than 90% and 85%, respectively. The missing seeding rates were 0%. The variation coefficients of plant spacing were less than 5%, indicating good stability of plant spacing, which met the design requirements. The study results can provide a theoretical reference for the optimization design of maize breeding equipment in a plot.

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