Abstract:  At present, the process of biochar return to the field is complicated, laborious and time‑consuming. In order to achieve the integration of trenching, biochar distribution, and soil covering for biochar return to the field, the key components for the biochar distribution system on the biochar return machine are designed, such as a trenching shovel and a biochar distributor. A simulation model of the key components is established by using the discrete element software Rocky to simulate the process of biochar return to field. The variability coefficient of biochar distribution  is taken as the experimental index, the exit distance, the diameter of the conduit and the angle of the deflector blade as experimental factors, the Design-Expert software is utilized to design a single‑factor experiment and a three‑factor, three‑level response surface experiment, the optimal working parameter combination is obtained through the analysis of response surface plots and parameter optimization modules, the outlet distance is 65.20 mm, the conduit diameter is 25.30 mm, and the baffle angle is 30°. The experimental results indicate that the variability coefficient of biochar distribution of the key components designed in this paper is 28.622% under the optimal working parameters, and the trenching, biochar distribution and soil covering process can be completed in one pass,  which can provide a reference for the technology of biochar return to field.

Key words:  biochar return to field, Rocky program, discrete element simulation, response surface test, parameters optimization

摘要： 当前生物炭还田过程烦琐，费时费力，为实现生物炭还田开沟—排炭—覆土一体化技术，设计适用于生物炭还田机上的排炭系统关键部件——开沟还田铲和排炭器。通过离散元软件洛基（Rocky）建立关键部件的仿真模型，模拟生物炭还田的工作过程。以炭量均匀性变异系数作为试验指标，出口距离、导管直径和挡板夹角为试验因素，运用Design-Expert软件设计单因素试验和三因素三水平响应面试验，通过分析响应面图和参数优化模块得到最优工作参数组合：出口距离65.20 mm、导管直径25.30 mm和挡板夹角30°。试验结果表明，在最优工作参数下，生物炭还田关键部件的炭量均匀性变异系数为28.622%，能一次性完成开沟、排炭还田、覆土工作，可为生物炭还田技术提供参考。

关键词: 生物炭还田, 洛基程序, 离散元仿真, 响应面试验, 参数优化