To correct the working state of a throwing component and achieve an ideal narrow, far, and uniform material projectile flow for a side-throwing device for organic fertilizer with inclined opposing discs, a systematic optimization of the auxiliary mechanisms (baffle, upper deflector, and side deflector) was performed. Starting from a basic analysis of the working principles of each side-throwing device component, theoretical modeling and MATLAB numerical calculations were used to determine the departure angle providing the farthest fertilizer distance, as well as the maximum and minimum throwing angles required to achieve a target distance of 10 m. These calculations informed the optimization and configuration of the basic structures of each auxiliary mechanism component. The impact of the baffle on fertilizer movement was analyzed, leading to an optimization of the baffle’s height and its horizontal position in relation to the main throwing disc, guiding the design of the discharge port structure. Combining the theoretical analysis results, the surface of the upper deflector was fitted, and a side deflector was added to assist in limiting the scattering angle of the projectile flow. An EDEM simulation showed that the optimized auxiliary mechanisms worked well together, resulting in a narrower discharge width, a more concentrated projectile flow, and improved uniformity in spreading. Prototype testing confirmed that from the side projection angle between the spreading direction and vertically upward, the projectile flow angle domain was adjusted from 18°-45° to 23°-32°. With the optimization of other auxiliary mechanisms, the coefficient of variation in spreading uniformity decreased from 25.95% to 19.21%, the effective throwing distance increased from 10.1 to 11.2 m, and the scattering angle decreased from 12° to 4°, effectively enhancing the performance of the side-throwing device.

To effectively obtain the downforce of the gauge wheels in real time, mechanical models of the interaction among the ground, gauge wheels, gauge wheel arms, and depth adjustment lever were constructed. A measuring method was proposed for monitoring the downforce through a two-dimensional radial sensing device, and a corresponding prototype was designed. Through simulation analysis of the sensing device with ANSYS, a 45° angle was determined to exist between the strain gauge axis and the sensing device axis, and the Wheatstone bridging circuit of R1+R3−R5−R7 (R stands for resistance strain gauge, different figures represent the strain gauge number) and R2+R4−R6−R8 was adopted. According to performance and calibration tests for the sensing device, the maximum interaction effect between the X and Y axes was 2.52%, and the output signal was stable and consistent. The standard error of the slope of the fitting equation of the downforce calculation model is 0.008. According to the field test, the average downforce of the gauge wheels was 1148, 1017, 843, and 713 N, at different sowing speeds of 6, 8, 10, and 12 km/h, respectively. The coefficients of variation were 0.40, 0.41, 0.62, and 0.71, respectively. The results indicate that the downforce fluctuation of the gauge wheels became more severe with increasing planting speed. Both the strain simulation analysis and field test verified that the measurement method is accurate and reliable, the performance of the sensing device is stable, the measurement method and sensing device meet the application requirements and lay a foundation for the research of accurate and stable control of downforce of no-till planter.