三七育苗播种覆土镇压装置的研究设计与试验

Design and experiment of soil covering and compacting device for Panax notoginseng seedling sowing

【目的】为提高三七育苗品质,针对槽式三七育苗播种行株距小、播深浅的特殊农艺要求,设计一种集覆土、镇压功能为一体的密集型种沟覆土镇压装置。【方法】在田间试验确定三七出苗率高、种苗品级最佳的基质紧实度范围的基础上,对镇压辊与土壤接触进行动力学分析,确定覆土镇压装置相关参数;借助离散元法对覆土镇压过程进行仿真分析;以开沟深度、播种机前进速度为试验因素,以覆土厚度及一致性为试验指标进行土槽试验,验证覆土镇压装置相关结构参数是否满足要求。【结果】由田间试验得到基质紧实度范围为200~400 kPa。覆土镇压装置结构参数为:镇压轮直径150 mm、弹簧最大刚度140.5 N/mm。由仿真分析得到覆土厚度为9.77~11.40 mm,粒距偏移量为0.07~6.23 mm,行距偏移量为0.03~1.43 mm。土槽试验结果表明,最优工作参数为:开沟深度为25 mm、播种机前进速度为0.16 m/s,此时覆土厚度均值为11 mm、覆土厚度一致性为85.15%,覆土镇压后基质紧实度为300~360 kPa。【结论】由仿真分析和土槽试验可知,覆土镇压装置设计满足三七育苗播种时基质紧实度和覆土厚度的农艺要求,研究结果可为三七覆土镇压装置设计提供参考。

【Objective】Aiming at the special agronomy of small row spacing and shallow sowing depth of slot type Panax notoginseng seedling,a compact soil covering and compacting device for seed ditch was designed to improve the quality of P.notoginseng seedlings.【Method】On the basis of the field experiment to determine the range of matrix compactness with high emergence rate and the best seedling grade of P.notoginseng,the dynamic analysis of the contact between roller and soil was carried out to determine the relevant parameters of the soil covering and compacting device.The process of soil covering and compacting was simulated and analyzed using discrete element method.Taking ditching depth and forward speed of the planter as test factors,the covering soil thickness and consistency as the test indexes,soil trough test was carried out to verify whether the relevant structural parameters of soil covering and compacting device met the requirements.【Result】The results of field experiment showed that the range of substrate compactness was 200 to 400 kPa.The structural parameters of the soil covering and compacting device were as follows:The diameter of the pressing wheel was 150 mm,and the maximum spring stiffness was 140.5 N/mm.The simulation results showed that the soil covering thickness was 9.77 to 11.40 mm,the offset of grain spacing was 0.07 to 6.23 mm,and the offset of row spacing was 0.03 to 1.43 mm.The results of soil trough test showed that the optimal working parameters were as following:The trench depth was 25 mm,the forward speed of planter was 0.16 m/s,the average covering thickness was 11 mm,the consistency of soil covering thickness was 85.15%,and the compactness of substrate after compaction was 300 to 360 kPa.【Conclusion】According to the simulation analysis and soil trough test,the design of the soil covering and compacting device can meet the agronomic requirements of substrate compactness and covering soil thickness for P.notoginseng seedlings.The research results can provide references for the design of soil covering and compacting device of P.notoginseng.