侧深施肥直斜偏置式免耕播种开沟器设计与试验

采用侧深施肥技术，施肥铲作业后播种带两侧土壤高度不一致，易加剧播种机横向偏摆，进而导致播种深度均匀性和播种横向一致性较差。为解决上述问题，该研究设计了一种直斜偏置式免耕播种开沟器。该开沟器主要由切土斜刃、挡土定位板、偏置推土板等组成，作业时滑切土壤并将其推移至肥沟一侧拓宽种沟，避免种子落至肥沟后位置过深，提高播种质量。通过离散元仿真试验，以前进阻力、肥沟回土深度、种沟回土深度为试验指标进行二因素五水平正交旋转组合试验，得到斜刃滑切角为37°、偏置角为15°时开沟器作业性能最好。在最优参数下与双圆盘式、尖角式开沟器进行田间作业性能对比试验，相对于双圆盘式和尖角式开沟器，直斜偏置式开沟器播种深度变异系数分别降低41.12%、19.41%；播种横向变异系数分别降低39.00%、28.41%；前进阻力分别降低7.26%、28.20%；作业后肥沟与种沟回土深度分别提高9.47%、13.68%和33.33%、7.14%。试验结果表明，该开沟器可以减小前进阻力，增加肥沟与种沟回土，提高播种深度均匀性和播种横向一致性，可为播种开沟器的设计提供参考。

Design and experiment of the straight oblique offset no-tillage sowing furrow opener with side deep fertilization

No-tillage sowing can effectively alleviate the spring drought for the high corn yield in northeast China. Side-deep fertilization can also avoid seed burning for the fertilizer supply in the middle and late periods of crops. Once the side deep fertilization is applied into no-tillage sowing, the soil height on both sides of the sowing belt can be inconsistent after the fertilizer shovel operation, leading to aggravating the lateral deflection of the seeder under the uneven distribution of surface straw stubble.It is very necessary to improve the sowing depth uniformity and lateral consistency. In this study, the straight-oblique offset furrow opener was designed to reduce the resistance to the increase in the soil backfill during no-tillage sowing, in order to improve the sowing depth uniformity and lateral consistency. The furrow opener was mainly composed of a cutting oblique edge, a retaining positioning plate, and an offset bulldozing plate. The soil was cut and pushed into the side of the fertilizer furrow to widen the seed furrow during the operation. The seeds falling was avoided after the fertilizer furrow for better sowing quality. Firstly, the force analysis was implemented on the offset bulldozing plate of the furrow opener. Among them, the horizontal force balance analysis of the side deep fertilizer shovel and the sowing furrow opener was also made to design the structure of the furrow opener. The height of the retaining positioning plate and the offset bulldozing plate of the furrow opener was determined to be 160 mm, and the bottom edge spacing between the retaining positioning plate and the offset bulldozing plate was 30 mm equal to the short side width of the shovel handle, the insertion gap angle was 8°, and the inclination angle was 10.6°. Secondly, the soil disturbance was analyzed before and after the operation of the straight-oblique offset furrow opener. The straight-oblique offset furrow opener increased the soil backfill of the fertilizer furrow and seed furrow. Finally, the sliding cutting of cutting oblique edge was clarified in the motion analysis of soil particles on the offset bulldozing plate. The structural parameters of the operation performance of the furrow opener were the oblique edge sliding angle and the offset angle. A discrete element simulation model of soil-stubble-straw was established using EDEM. The three-dimensional models of stubble cutter, fertilizer shovel, and furrow opener were imported into EDEM for simulation experiments. The structural parameters of the furrow opener were optimized by a two-factor and five-level orthogonal rotation combination experiment with forward resistance, the backfill depth of the fertilizer furrow and the backfill depth of the seed furrow as experiment indexes. The optimal combination of parameters was achieved in the oblique edge sliding angle of 37° and the offset angle of 15°. A field experiment was conducted with the double disc and sharp-angle furrow openers under optimal parameters. The sowing depth variation coefficient of straight-oblique offset furrow openers was 41.12% and 19.41% lower than those of double disc and sharp angle furrow openers, respectively. The sowing lateral variation coefficients decreased by 39.00% and 28.41%, respectively. The forward resistance was reduced by 7.26% and 28.20%, respectively. The backfill depth of the fertilizer furrow increased by 9.47% and 13.68%, respectively after optimization. The backfill depth of seed furrow increased by 33.33% and 7.14% respectively. The furrow opener reduced the forward resistance, while improving the soil backfill of the fertilizer furrow and seed furrow for the sowing depth uniformity and sowing lateral consistency. The finding can provide a strong reference for the design of the seeding furrow opener.