小麦分引组合式双行宽条带导种装置设计与试验

针对稻茬田小麦机械化带状播种时受黏重土壤与秸秆还田耦合作用制约存在导种装置壅堵导致断条的问题，该研究设计了一种分引组合式双行宽条带导种装置，导种过程中利用球面弹籽部件对下落种群左右均匀分种、借助坡度斜面对分流种群宽带引种。运用质点运动学理论建立了小麦分种、引种过程的力学模型，明确了球面弹籽部件直径和斜面坡度对导种均匀性有影响。运用EDEM软件对小麦导种装置关键结构参数进行优化设计，以球面弹籽部件直径和斜面坡度为试验因素，以各行排量一致性变异系数和行内横向均匀度变异系数为评价指标，通过单因素和二次正交旋转组合试验获取相关试验数据，应用Design-Expert软件对试验数据进行回归分析，建立了试验因素与试验指标之间的回归方程。结果表明，球面弹籽部件直径对各行排量一致性影响显著（P＜0.05），斜面坡度对行内横向均匀度有极显著影响（ P＜0.01 ），斜面底板导种装置最优结构参数为球面弹籽部件直径40 mm、斜面坡度10°。并与市场上已有的波浪底板、弧面底板、平面底板3种型式导种装置进行3种播量下的仿真对比试验。仿真试验结果表明，各播量下的各行排量一致性变异系数和行内横向均匀度变异系数由大到小均为平面底板、弧面底板、波浪底板和斜面底板型导种装置，在播量450 kg/hm²下，斜面底板型导种装置播种效果最佳，各行排量一致性变异系数为2.92%，行内横向均匀度变异系数为14.19%。台架与田间对比试验表明，斜面底板型导种装置的各行排量一致性变异系数和行内横向均匀度变异系数均最小，此时各行排量一致性变异系数均不大于4.0%，行内横向均匀度变异系数均不大于16%；田间对比试验中，在播量450 kg/hm²下，斜面底板型导种装置较其他3种导种装置各行排量一致性变异系数最低下降了2.73个百分比，行内横向均匀度变异系数最低下降了10.61个百分点。试验结果与仿真结果误差不超过5%，表明装置结构参数优化结果可靠，满足国家播种机质量评价技术规范及大田播种农艺要求。研究结果可为稻茬黏壤土环境下小麦宽条带导种装置优化设计提供参考。

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 coefficient of variation of each row seeding quantity consistency was not more than 4.0%, whereas, the coefficient of variation of transverse uniformity in row was not more than 16%. 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.