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The gas–solid flow of mixed seeds of oat and vetch in the air-blowing venturi tube was simulated numerically by means of a coupling approach of the discrete element method (DEM) and computational fluid dynamics (CFD). In the gas–solid coupling model, EDEM software was used to depict the discrete particle phase, and ANSYS Fluent software was used to describe the continuous gas phase. The effects of the seed entry angle and inlet air velocity on the uniformity of mixed seed supply were studied and analyzed from the angle of airflow field variation and mixed seeds movement characteristics. The simulation results showed that the seeding angle has a great influence on the seed movement in the tube and affects the pressure and velocity gradient of the airflow field. If the seed insertion angle is too large, the number of collisions between the seed and the tube wall will increase, and the phenomenon of seeds retention and disordered jumping will occur. The inlet air velocity mainly affects the outlet air velocity and seed velocity and has little effect on the change in airfield. With the increase in inlet air velocity, the greater the velocity and force of the seeds, the closer the mixed seeds collide with the wall to the outlet pipe. At high inlet airflow velocity, there is a great disparity in the movement speed between the seeds, resulting in uneven spacing between the seeds. The results showed that under the conditions of 60° seed entry angle and 35~40 m/s inlet air velocity, the airflow field distribution in the tube was uniform and the seed movement was continuous and uniform.

Background: Astragalus membranaceus seeds have dormant properties that not only limit germination but also negatively affect the growth of seedlings. We investigated the enhancing effect of cold plasma treatment on seed germination and the positive effect on seedling growth of Astragalus membranaceus by treating its seeds with cold plasma at different power levels. Method: The Astragalus membranaceus seeds were treated with cold plasma at power levels of 40, 60, 80, 100, 120, 140, 160, 180, 200, 220 and 240 W for 15 seconds with helium gas and seeds without any treatment were used as control. Results: The Astragalus membranaceus seeds were treated with cold plasma, which not only improved seed germination, but also had a positive effect on seedling growth, with the best results for the 80 W power cold plasma treatment. The 80 W power cold plasma treatment increased the germination rate, germination index and vigor index of Astragalus membranaceus seeds by 26.8%, 12.4% and 39.8%, respectively; increased root length, CAT activity and SOD activity of Astragalus membranaceus seedlings by 24.5%, 99.7% and 7.1%, respectively and decreased the relative conductivity and MDA content of Astragalus membranaceus seedlings by 6.6% and 17.6%, respectively; compared with that of the control group.

： Agriculture occupies an important position in our national economy and raising the level of agricultural mechanization of agricultural production can reduce labor intensity. Research and development of agricultural robot at home and abroad are to further improve the agricultural production efficiency and automation level. According to the difference of agricultural robot and traditional industrial robots, the paper summarizes the agricultural robot‘s special aspects, which include working object, working environment, action and operator etc. Further study summarized the main results of the present study of agricultural robot at home and abroad. According to the structural characteristics of agricultural robot, the robots are divided into a series of walking robot and manipulator robot. On the basis of this research, this paper further puts forward the key technology in the development process of agricultural robot , which mainly comprises a machine vision and image processing technology , target detection and location technology , autonomous navigation and path planning technology , information fusion technology and intelligent control technology. In the mean time, the key technology research decides the development direction of agricultural robot. Basing on the lack of agricultural robot in the present research, this paper further puts forward the bottleneck which needs to break through in the future development process of agricultural robot, mainly including intelligent recognition and positioning, the robot's versatility, structure optimization design. These aspects make agricultural robot in domestic applications more widely, improve the efficiency of agricultural production and promote the development of agriculture in our country..