As the complex terrain in hilly areas is not conducive to corn mid-tillage precision fertilization, a corn-overlapped strip fertilizer spreader was designed without an external power source. By configuring a passive overlapping spreading method with a three-branch split chamber structure, the uniform spreading of fertilizer in strips was achieved. A horizontal and vertical movement model of fertilizer spreading was developed to determine the angle of the fertilizer extending tube, the width of fattening small plates, and the height of the fertilizer spread as the main factors affecting the fertilizer distribution pattern. The single-factor ternary orthogonal rotational combination response surface simulation test was carried out with pendulum angle, width, and height as test factors and the transversal fertilizer uniformity coefficient and longitudinal fertilizer uniformity coefficient as test indicators. The test results showed that the pendulum angle, height, and width had significant effects (p < 0.05) on the transversal fertilizer uniformity coefficient, and the pendulum angle and width had a considerable impact (p < 0.05) on the longitudinal fertilizer uniformity coefficient. In the optimal combination of parameters, swing angle 52°, height 400 mm, and width 50 mm operation, the coefficients of uniformity of both the transversal fertilizer uniformity coefficient and longitudinal fertilizer uniformity coefficient were less than 0.15%. A verification test was carried out under the optimal combination of parameters for the simulation tests with the simulation conditions as the standard. The test results were consistent with the simulation results within the error range. The deviation values of the transversal fertilizer uniformity coefficient and longitudinal fertilizer uniformity coefficient were 8.11% and 9.01%, respectively. The corn-overlapped strip fertilizer spreader was able to complete the fertilizer spreading operation smoothly. This study provides evidence for further optimizing the performance of the corn mid-tillage fertilizer applicator.

Precision fertilizer application technology is necessary to improve fertilizer utilization efficiency in agricultural production. To achieve precision fertilizer application and solve problems in production practice that contain the structure problem of the traditional mechanical fertilization systems, and the fertilizer discharger is blocked and can not achieve uniform fertilization because the fertilizer contains caking fertilizer in response to the characteristics of conventional fertilizers containing caking fertilizers, innovative design and system experimental simulation studies were carried out. A gap squeeze gear-type fertilizer dis-charger was designed, and fertilizer caking crushing was achieved by configuring the gear gap squeezing method. Combined with engineering practice, two mixed fertilizers (granular fertilizer with caking fertilizer) were constructed and blended by using BPM (Hertz Mindlin with bonding) discrete element, the fertilizer discharger was used as the object of study to simulate and experimentally investigate the process of crushing and discharging of mixed fertilizer and the process of uniform discharging of mixed fertilizer. The simulation test model of the separation device with vibration screen of the caking fertilizer and granular fertilizer after fertilizing was established to study the crushing rate of the caking fertilizer, and the simulation model with collection plate of the uniformity of the mixed fertilizer discharge was based on to explore the uniformity of the mixed fertilizer. The L₉ (₃⁴) orthogonal test was carried out under the conditions with the number of teeth, pressure angle, and fertilization gap as test factors and the fertilizer crushing rate and fertilizer uniformity coefficient as test indicators. The test results showed that the number of teeth and pressure angle had significant effects (0.01 < P < 0.05) on the crushing fertilizer rate and fertilizer uniformity, and the fertilization gap had no significant impact (P༞0.05) on the crushing fertilizer rate and fertilizer uniformity. In the optimal combination of parameters, the number of teeth 6, pres-sure angle 15 °, fertilization gap 6mm operation, the coefficient of uniformity of crushing fertilizer rate and fertilizer uniformity were 74.89% and 17.21%, respectively. The bench test results compared with the outer groove wheeled fertilizer drainer showed that the optimized gap squeeze gear type fertilizer discharger has higher fertilizer crushing quality at different speeds, and the fertilizer crushing rate and uniformity were79.69% and 18.56%, respectively, within the error range. The simulation results are in general agreement. This study provides evidence for fertilizer discharger structure design and enhances the effect of fertilizer discharger crushing.