## 5 Conclusions  
1. Combined with the characteristics of sandy orchards cultivation in South Xinjiang. A ditching organic fertilizer fertilization device was designed, the relevant parameters of the ditching blade were set, and the kinematic analysis of the ditching blade and the motion analysis of soil particles under the action of the fairing were carried out, the theoretical soil throwing model of the test setup was obtained. It can be seen from the soil throwing distance model that the throwing distance of soil particles is related to the rotating speed of the cutter wheel, the position of the cutter wheel blade, and the soil particles in the z-axis direction. In addition, the velocity before collision is also affected by the dip angle \(\alpha\) of the fairing. Thus, the throwing distance is also related to the dip angle of the fairing. This throwing distance model does not take into account the change of sandy soil particles' speed due to their deformation caused by collision. 2. Discrete element simulation was carried out on the ditching device by EDEM simulation software, and the action mechanism between soil particles, ditching blade and fairing was obtained in simulating ditching operation. Make it clear that the trenching process. The movement of soil particles in the deflector hood under the action of the blade, the conclusion is consistent with the results of the theoretical analysis. When opening the trench, some of the soil continued to move in a circle with the cutter head, and some was thrown out of the ditch; meanwhile, it can be seen that as soon as one blade crossed the soil and continued the trenching, another blade came into contact with the soil, indicating that there was overlapping soil cutting section between adjacent ditching blades, a large number of soil began to move in a circle with the cutter head. When it was lifted to a certain height, some soil particles were thrown out of the cutter head and collided with the fairing, and then were thrown out. Furthermore, due to low viscosity and fineness of sandy soil, not all soil will collide against the fairing. Therefore, some soil will still escape from the seams of fairing. 3. Cutter speed, ditching depth and the inclination of curved surface on the throwing distance and the stability of ditch depth were obtained through soil trough test. For the stability of ditch depth, the ditch depth was smaller than the cutter wheel speed and the inclination angle. Ditching depth also has the greatest influence on the stability of ditch depth. The order of the influence of each factor on the soil throwing distance is ditching depth > inclination of curved surface > cutter speed, and the order of the influence on the stability of the ditch depth is ditching depth > cutter speed > inclination of curved surface. At a certain ditching depth, the influence of both inclination of curved surface and cutter speed on the throwing distance and the stability of ditching depth increased first and then decreased, and the influence of cutter speed was greater than that of the inclination of curved surface. For the soil throwing distance, it has the greatest influence on the soil throwing distance. It further shows that the ditching depth has the most important influence on the soil throwing distance and the stability of the ditch depth of the trenching equipment. The quadratic orthogonal regression rotation combination experiment method was designed. The device test was carried out by taking cutter speed, ditching depth and inclination angle of the fairing surface as the influencing factors, and the throwing distance and the stability of ditch depth as the test indexes, to obtain the optimized working parameters.