关键词: 秸秆还田, 土壤颗粒, 秸秆颗粒, 运动轨迹, 翻埋运动

Abstract: The process of rice straw and soil burial is an important factor affecting the return of straw to the field. In this paper, based on the previously established simulation model of the interaction between the straw return knife roller, soil, and rice straw, the motion state of soil particles was further studied. When the tillage depth was 20cm, the rotation speed of the cutter shaft was 240r/min, and the unit straw amount was 3.5kg/m2, simulation and indoor experiments were carried out with the straw burial rate and returning depth as the test indicators. The results showed a burial rate of 87.5% and 86.7% and a returning depth of 19.16 cm and 18.68cm, respectively, which validated the simulation and met the requirements of national standards. The simulation results showed that when the calibrated particle 152658 was in contact with the knife roller, it initially moved backward and downward. After reaching the lowest point, it was thrown backward and upward due to the rotation of the knife roller. The movement trajectory was approximately parabolic. The particle then fell back to the ground under the influence of gravity. It collided with other particles and generated fluctuations until it finally came to rest. The soil stress was studied by randomly calibrating the particles. The results showed that when the knife blade first contacts the soil particles, the forces in the X, Y, and Z directions of the particles increased linearly, and the maximum values were 15.61N, 37.2N, and 50.37N, respectively. After the soil particle mass was chopped by the knife blade, the force gradually decreased to 0. Similarly, by calibrating straw particle 45681 and analyzing its movement trajectory, the simulation showed that soil particles initially exhibited a dual effect of promoting and inhibiting the straw velocity. As the soil returned to the surface, the straw was mainly affected by soil friction under the soil layer until the straw velocity dropped to 0. The simulation analysis revealed the working principle of the straw return knife blade for straw burial and returning to the field from a microscopic point of view and provided theoretical support for the optimal design of components.

Key words: straw returning, soil particles, straw particles, movement trajectory, burial movement