Design, simulation and experimental study on elliptical-groove spiral intermittent precision fertilization device for maize intermittent banding fertilization

To meet the matching fertilization requirement under the unequal-spacing triangular planting pattern of corn, an unequal-spacing intermittent banding segmented fertilization device was de-signed. To make the fertilizer discharged by the fertilizer distributor satisfy agronomic standards and guarantee intra-strip fertilizer uniformity and stable intermittent banding spacing, in-depth research on the fertilizer discharging device was carried out. An incomplete gear intermittent transmission mechanism was adopted to convert continuous rotation into intermittent rotation, driving the elliptical spiral groove to rotate intermittently and realizing intermittent fertilizer dis-charge instead of continuous output, so as to achieve segmented fertilizer distribution. This paper focuses on the design and parameter optimization of an elliptical-groove spiral intermittent fertilizer distributor. By adjusting the groove shape and setting a deflection angle, fertilizer can smoothly enter and exit the discharge groove; optimizing the helix angle reduces the fluctuation of fertilizer flow at the groove ridge and improves intra-strip uniformity. Periodic start-stop movement realized by incomplete gear transmission enables intermittent fertilizer cutting-off. A three-factor five-level quadratic general rotary composite design test was conducted, taking elliptical groove deflection angle, helix angle and effective working length as test factors, and intra-segment uniformity fluctuation coefficient and segment spacing variation coefficient as response indexes to solve for the optimal parameter combination. Test results show that the elliptical groove deflection angle and effective working length exert an extremely significant effect on segment spacing variation coefficient ( P < 0.01). The elliptical groove deflection angle, helix angle and effective working length all have extremely significant influences on intra-segment fertilizer discharge uniformity fluctuation coefficient. The optimal structural parameter combination is determined as follows: elliptical groove deflection angle of 2.61°, helix angle of 79.15°, and maximum effective working length of 70 mm. A prototype fertilizer distributor was manufactured with the optimized parameters for bench tests. Bench test results demonstrate that the average intra-strip uniformity fluctuation coefficient reaches 16.90%, and the segment spacing variation coefficient is 9.74%. The relative errors compared with simulation results are only 28.68% and 19.54%, respectively. The simulation data show a consistent trend with the bench test measurements. The developed elliptical-groove spiral intermittent fertilizer distributor can accurately perform periodic fertilizer cutting-off, which provides references for structural design and parameter matching of intermittent fertilization equipment.