Design and experiment of the soil-covering and soil-compacting device for seedling raising and sowing of trough type panax notoginseng

In order to improve the seedling quality of Panax notoginseng, combined with the special agronomic requirements of Panax notoginseng, a sharp angle roller soil-covering and soil-compacting device integrating the functions of soil-covering and soil-compacting was designed. Based on the theoretical analysis of seed ditch conditions, soil-covering process and soil-compacting process, the structure of soil-covering and soil-compacting device was designed. Through theoretical analysis and calculation, the diameter and length of soil-covering and soil-compacting wheel were 20 cm and 10.7-14.1 cm, respectively, the sharp angle and height range were 45°-105° and 0.8-1.6 cm respectively, and the spring stiffness was 38.54 N/mm; Using the discrete element method to simulate the soil-covering and soil-compacting process, it was obtained that when the sharp angle range was 60°-90°, the sharp angle height range was 0.8-1.2 cm, and the soil-covering effect was better; Taking the forward speed, ballast pressure, sharp angle and sharp angle height of the planter as the test factors, and taking the soil-covering thickness, grain spacing and soil compactness as the indexes, the four factor and three-level Box-Behnken Design test was carried out. The response surface test analysis method was used to establish the regression equation between the factors and indexes, and determine the best parameter combination: the forward speed was 6.5 m/min, the ballast pressure was 360.5 N, the sharp angle was 67°, and the sharp angle height was 1 cm, at this time, the soil-covering thickness was 0.64 cm, the grain spacing was 5.03 cm, and the soil compactness was 321.77 kPa. According to the soil trough test, the design of soil-covering and soil-compacting device met the agronomic requirements of plant spacing, soil-compactness and soil-covering thickness during seedling sowing of Panax notoginseng. The research results can provide a reference for the design of Panax notoginseng seedling planter integrating pressing hole (ditching), sowing, soil-covering and soil-compacting.