Design and test of the separate and combined double row wide strip seed guiding device for wheat

Aiming at the problem that mechanized strip sowing of wheat in rice stubble fields can be constrained to the coupling effect of clay-heavy soil and straw return to the field. The seed guide device can be blocked to cause the breakage. In this study, a double-row wide strip seed introduction device was designed to combine with the spherical collision seed part, in order to evenly divide the falling population left and right during introduction. The broadband introduction of the diverted population was also carried out with the help of beveled bottom plate slope. The mechanical model of wheat seeding and introduction was established using particle kinematics. A systematic investigation was implemented to clarify the influencing mechanism of the spherical collision seed part diameter and beveled bottom plate slope on the uniformity of seed introduction. EDEM software was then used to optimize the key structural parameters of the wheat seed introduction device. Among them, the spherical collision seed part diameter and beveled bottom plate slope were taken as the test factors. The evaluation indexes were taken as the coefficient of variation of each row seeding quantity consistency and coefficient of variation of transverse uniformity in row. The test data was obtained to combine the univariate and quadratic orthogonal rotation. Design-Expert software was also selected to perform the regression analysis on experimental data. The regression equation was established between the test factors and indicators. The results show that the spherical collision seed part diameter posed a significant coefficient of variation of each row seeding quantity consistency, whereas, the beveled bottom plate slope was some impact on the coefficient of variation of transverse uniformity in row. The optimal structural parameters were achieved in the seed guiding device spherical collision seed part diameter of 40mm, and the beveled bottom plate slope of 10°. The beveled bottom plate guide device was evaluated under optimal structural parameters. Three types (flat plate,curved bottom plate,wavy plate) of seed guide devices were selected to compare under the three sowing amounts. The simulation results show that the coefficient of variation of each row seeding quantity consistency and coefficient of variation of transverse uniformity in row were ranked in the descending order: flat plate,curved bottom plate,wavy plate,beveled bottom plate. The optimal coefficient of variation of each row seeding quantity consistency was 2.92% of the beveled bottom plate-type seed guiding device. The coefficient of variation of transverse uniformity was 14.19% in the row. The bench and field tests were combined to further verify the smallest coefficient of variation of each row seeding quantity consistency and coefficient of variation of transverse uniformity in row of the beveled bottom plate seed guiding device. Specifically, the mean coefficient of variation of each row seeding quantity consistency was 2.31%, whereas, the mean coefficient of variation of transverse uniformity in row was 14.21%. The field experimental results showed that coefficient of variation of each row seeding quantity consistency decreased by at least 2.73 percentage points, and the coefficient of variation of transverse uniformity in row decreased by at least 10.61 percentage points, compared with the other three types of seed guide devices. The error was not more than 5% between the actual and the simulation. Therefore, it was reliable for the optimized structural parameters of the split-citation combined wide strip guide device using the discrete element method. At the same time, the national technical specifications were fully met for the quality evaluation of seeders and the agronomic requirements for field seeding. The findings can provide a strong reference for the optimal design of wheat wide strip seed introduction device under a rice stubble clay loam environment.