基于离散元的肥料流重构玉米分层施肥装置设计与试验

Design and Experiment of Corn Layer Fertilization Device with Fertilizer Flow Reconstruction Based on Discrete Element Method

摘要:

为了提高玉米分层施肥的比例分肥精度以及肥层间覆土的稳定性，设计了一种肥料流重构的分层施肥装置，利用离散元法确定了圆弧散肥板半径的最佳值为20 mm，并进行了肥料流重构与未重构的对比试验，试验结果表明：经过肥料流重构后的作业效果较优，且对7∶3和8∶2两种比例分肥有较好的稳定性。通过对分层施肥开沟运动学分析，确定开沟器入土角、浅层肥口的横向距离和机具作业速度为分层施肥效果的影响因素，建立了各因素与深、浅层肥深度变异系数的回归模型，并采用响应面法分析了各因素交互作用对试验指标的影响，运用多目标优化设计方法获得分层施肥装置的最佳作业参数：入土角为39°、横向距离为174 mm、作业速度为4.3 km/h，根据优化结果加工分层施肥装置并进行田间试验，试验结果表明：深层肥深度变异系数为4.78%，浅层肥深度变异系数为6.41%，分层施肥作业稳定性可靠。

Abstract:

To enhance the accuracy of proportional fertilizer distribution for corn layered fertilization and the stability of soil coverage between layers, a layered fertilizer flow reconstruction apparatus was developed. The optimal diameter of the circular bulk fertilizer disc was determined to be 20 mm by using the discrete element method. Subsequently, a comparative test was carried out between fertilizer flow reconstruction and non-reconstruction. The results demonstrated that after fertilizer flow reconstruction, the operational efficiency was improved, and the stability of both 7∶3 and 8∶2 ratio fertilizers was enhanced. By conducting kinematic analysis of ditching for layered fertilization, it was established that the trencher’s angle, the lateral distance of the shallow fertilizer opening, and the machine’s operating speed were key factors influencing the efficacy of layered fertilization. A regression model was formulated to correlate the variation coefficient of each factor with the depth of deep and shallow fertilizers. The impact of the interaction of each factor on the test index was then analyzed by using the response surface method. By using the multi-objective optimization design method, the optimum operation parameter insertion angle of the layered fertilizer applicator was 39°, the transverse spacing was 174 mm, and the operation speed was 4.3 km/h. Based on the optimized parameters, the layered fertilization device was manufactured, and field tests were conducted. The results revealed that the variation coefficient of deep fertilizer depth was 4.78%, while that of shallow fertilizer was 6.41%. The stratified fertilization operation exhibited stability and reliability. The research result can offer a theoretical and methodological foundation for the design of layered fertilization devices.