Abstract
The objective of this research was to enhance the precision of seed placement in the John Deere pneumatic planter by improving the design of its seed delivery system within the seeding section. The upgraded seeding section incorporated several key components: an upper and lower seed sensor, a seed retarder composed of a perforated cylinder with holes, upper and lower narrowing nozzles, a cylindrical shutter with a rigidly mounted curved toothed rack, and a servo drive with a gear wheel. These modifications aimed to improve seed distribution uniformity and optimise planting accuracy. Numerical simulations of the seed retarder, conducted using the Simcenter Star-CCM+ software package, allowed for the visualisation of both seed movement and airflow dynamics within the working area of the retarder. Regression equations of the second order were formulated based on numerical simulations and data processing in the Wolfram Cloud software package. These equations, refined by removing insignificant coefficients in accordance with the Student’s t-test, described the dependencies of key parameters: the air velocity at the seed retarder’s outlet (Vaout), the seed velocity at the outlet (Vpout), and the seed rate change coefficient (η) as functions of the inlet air velocity (Vain) and the ratio of the outlet area to the inlet area (ε). According to agronomic standards, the permissible seed rate deviation should not exceed 1%. Comparative numerical simulations were performed for both the standard and modified designs of the John Deere 90 Series pneumatic seeder’s seeding section. The results indicated that the improved design yielded superior performance, ensuring more uniform seed placement. The spacing between seeds in the modified version ranged from 0.0404 m to 0.0493 m, with a coefficient of variation of 0.223, corresponding to an average spacing of 0.0448 ± 0.004 m. These findings confirmed that the enhanced seeding section meets the required precision standards for optimal seeding accuracy, leading to improved crop establishment and yield potential. The research results can be used for further optimisation of pneumatic seeders to improve seeding accuracy and reduce yield losses