Development of Stalk Cleaning Device of Maize High-speed No-tillage Seeder on Seeding Belts

Conservation tillage is a modern agricultural technology with stalk returning and no-tillage seeding as the core, which improves soil physical and chemical properties, protects soil fertility and increases crop yields by reducing soil disturbance and increasing stalk coverage. In Northeast China, with the improvement of the level of agricultural mechanization, long-term high-intensity tillage and stalk burning have caused the decline of soil organic matter content and serious erosion, so it is necessary to carry out conservation tillage in this area. At the same time, with the popularization of high-speed seeding technology in the world, the existing no-tillage seeder anti-blocking device is difficult to meet the demand of high-speed no-tillage seeding in Northeast China. In this study, based on the agronomic mode of double-row planting of large ridges widely used in Northeast China, a combined seeding belt stalk cleaning device suitable for high-speed no-tillage seeding operation was designed, which was composed of a pair of drive discs and stalk cleaning teeth. The disc blade curve is a kind of normalized curve variable parameter logarithmic spiral, which analyzes the dynamic sliding cutting characteristics under the curve operation through the dynamic sliding cutting principle, and intercepts the curve, which has the characteristic that the dynamic sliding cutting angle is stable at 22.5°, and the number of curve of the disc is further determined to be 18 by the method of kinematic analysis. The two sides of each disc are respectively provided with the stalk cleaning teeth, and the stalk in and outside the ridge is cleaned respectively in the operation process, and the structural parameters, spatial parameters and operation parameters of the stalk cleaning teeth are determined by the method of parameter analysis. In order to clarify the interaction mechanism between the device and the stalk under high-speed operation, the simulation experiment was carried out by using the discrete element method, and the ridge soil model was established by using the Hertz-Mindlin with Bonding model, and the maize stalk flexible body with lengths of 130mm, 150mm and 170mm was designed, respectively. Through the positioning and laying of stalk at different angles, the stalk cleaning effect under different declination angles of the device was analyzed, and the range of deflection angles was determined to be 30～75°. On this basis, a ridge soil model with a stalk covering amount of 1.66kg/m² was constructed, and the quadratic regression rotation orthogonal experiment was carried out based on the factors of operation speed, inner declination angle and outer declination angle, the data were processed and analyzed by Design-Expert software, and the optimal parameters of the device were obtained: the deflection angle of the inner stalk cleaning teeth was 45.3° and the deflection angle of the outer stalk cleaning teeth was 75.0°. According to this parameter, the average working power is 7.653kW, the stalk cleaning rate is 95.00%, and the errors are 3.06% and 1.35%, respectively. In order to verify the performance of the device under different stalk covering amounts, the stalk covering amounts of 2.06kg/m², 1.59kg/m² and 0.87kg/m² were selected to carry out field experiments, which respectively correspond to small, medium and large stalk covering, and the results of field experiments showed that: At the operating speed of 3.0m/s, when the stalk covering amount is 2.06kg/m², the stalk cleaning rate of the anti-blocking device is 86.7%, and the average operating power is 10.460kW. When the stalk covering amount is 1.59kg/m², the stalk cleaning rate of the anti-blocking device is 92.2%, and the average operating power is 9.024kW. When the stalk covering amount is 0.87kg/m², the stalk cleaning rate of the anti-blocking device is 96.1%, and the average operating power is 8.219kW, which is ideal for the operating performance of the device. The device meets the needs of no-tillage seeding operations under different stalk covering rates in Northeast China, and can provide a theoretical and technical reference for the research and development of anti-blocking devices under high-speed operation.