山地拖拉机坡地等高线旋耕土壤侵蚀规律研究

针对黄土高原丘陵山区坡地等高线旋耕作业时土壤耕作侵蚀(土壤由坡高侧向坡低侧迁移)严重及其机理不明等问题，通过理论分析、仿真试验、土槽及实地试验相结合的方法，深入开展山地拖拉机坡地旋耕侵蚀规律研究。首先，构建了H245标准型常用旋耕刀在坡地工况下的扰土体积参数方程，完成了旋耕刀坡地扰土过程的经典力学分析，确定了导致坡地旋耕土壤侵蚀的主要影响因素：坡地角、耕作深度、刀轴转速以及旋耕作业速度；然后，基于EDEM离散元仿真软件研究了单把旋耕刀和旋耕机整机的坡地扰土规律，得出土壤颗粒在旋耕刀侧切刃的动态滑切作用下有水平向后运动的行为，浅层土壤颗粒位移最大，深层土壤颗粒位移最小，并且深层靠近旋耕刀回转中心的土壤颗粒位移最大；土壤的侧向位移方向受旋耕刀正切刃朝向的影响；随着旋耕刀的入土，土壤颗粒在垂直方向的位置呈先变深后变浅的趋势。最后，选取旋耕刀轴转速、旋耕作业速度和坡地角作为试验因素，进行了实地旋耕单因素和正交试验，单因素试验得到土壤水平、侧向位移随着上述3个因素变化的规律；正交试验方差分析得到影响土壤侧向位移的主次因素为坡地角、旋耕刀轴转速、旋耕作业速度，影响土壤水平位移的主次因素为旋耕作业速...

Soil Erosion Law of Contour Rotary Tillage of Hillside Tractoron Sloping Land

Aiming at the problem of soil tillage erosion (soil migration from the higher side of the sloping land to the lower side) and its unknown mechanism during the contour rotary tillage operation of the slopes in the hilly and mountainous areas of the Loess Plateau. Through the combination of theoretical analysis, simulation test, soil trough and field test, the research on the erosion mechanism of rotary tillage by hillside tractor on sloping land was carried out in depth. Firstly, the parameter equation of soil disturbing volume of H245 standard rotary blade under sloping conditions was constructed, the classical mechanical analysis of the soil disturbing process of the rotary blade was completed, and the main influencing factors of soil erosion were determined: tillage depth, rotary blade shaft speed and rotary tillage forward speed. Then, based on the EDEM simulation software, the soil disturbance law of a single rotary blade and the whole rotary cultivator was studied, and it was concluded that the soil particles moved backwards under the dynamic sliding action of the side cutting edge of the rotary blade. The displacement of soil particles in the shallow layer was the largest, the displacement in the deep layer was the smallest, and the displacement of soil particles in the deep layer near the rotation center of the rotary blade was the largest. The lateral displacement direction of soil was affected by the direction of the tangential edge of the rotary blade, and the bending angle of the tangential edge largely determined the lateral throwing effect of soil particles. The vertical position of soil particles showed a trend of becoming deeper and then shallower as the rotary blade was immersed in the soil. Finally, the single factor and orthogonal tests of rotary tillage were carried out on the spot with the rotational speed of the rotary tiller shaft, the rotational tillage speed and the slope angle as the test factors. The single factor test obtained the law of soil horizontal and lateral displacement changing with the above three factors. The variance analysis of the orthogonal test showed that the factors affecting the lateral displacement of the soil were the slope angle, the rotational speed of the rotary tiller shaft, the speed of the rotary tillage, and the factors affecting the horizontal displacement of the soil were the speed of the rotary tillage, the slope angle, and the rotational speed of the rotary tiller shaft. The regression equation between the soil lateral displacement, the horizontal displacement and the independent variables was obtained by fitting, and the optimal operating parameters combination of the rotary tiller was determined under the five setting slope angles through parameter optimization. The research result can provide good technical guidance for the high-efficiency and low-erosion operation of the existing rotary cultivator in the sloping tillage area of the Loess Plateau, and it can also provide research ideas for the innovative design of the subsequent rotary cultivator for sloping land.