In light of the agricultural development in China, more attention has been paid to the studies about precision agriculture. The environmental factors such as temperature-humidity and soil humidity are the key influencing factors on crop growth, therefore, how to rapidly and accurately acquire the environmental information of crop growth and learn about their real-time growing environment is of vital importance. The wireless sensor networks (WSN) can make real-time environmental information acquisition as well as communication and processing of network environmental data. Based on this, the RSSI range-based positioning method was optimized in this paper in order to greatly improve its precision. To be specific, in this study, the particle swarm optimization (PSO) algorithm was firstly applied in the hybrid mutation strategy to make more accurate node positioning and significantly improve the evolutionary performance by enlarging the hunting zone; besides, through the use of WSN, the influencing parameters on crop growth such as soil humidity, and temperature-humidity etc. would be monitored; finally, to realize the precise location and derive the unseeded nodes, GPS was applied for accurate positioning, and the intelligence algorithm was adopted to determine the coordinate position of unknown nodes. At last, the actual field test indicates that the designed monitoring system in this paper satisfies the requirements for precise measurement, playing a positive role in promoting the development of precision agriculture.

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. Key words: Panax notoginseng, trough type, seedling raising and sowing, soil-covering and soil-compacting, EDEM, test DOI: 10.25165/j.ijabe.20231605.7606 Citation: Yang W C, Pu W, Xu L L, Tian Z Y, Zhao J, Zhang Y J, et al. Design and experiment of the soil-covering and soil-compacting device for seedling raising and sowing of trough type panax notoginseng. Int J Agric & Biol Eng, 2023; 16(5): 113–122.

This study is aimed to solve the parameter shortage during discrete element method (DEM) simulation in mechanized deseeding of fresh Rhizoma polygonati, and to calibrate DEM simulation parameters of fresh R. polygonati using physical measurement and simulation trials. First, the physical properties of fresh R. polygonati from picking to 15 days of stacking, and the contact parameters between fresh R. polygonati and different materials along with the prolonging of stacking days were measured through physical experiments. Based on the physical test results, the parameters significantly affecting the repose angle of fresh R. polygonati were screened out via Plackett-Burman test. The collision recovery coefficient, static friction coefficient, and rolling friction coefficient between fresh R. polygonati fruits all significantly affected the repose angle of fresh R. polygonati. On basis of Plackett-Burman test, a steepest ascent test was designed to further clarify the ranges of the significant parameters. Targeting at the actual repose angle of fresh R. olygonati (27.23°), we conducted Box-Behnken test and obtained the optimal parameter combination for DEM simulation of fresh R. polygonati. Verification tests showed the relative errors between the simulated values and measured values of repose angle in fresh R. polygonati were less than 3%, which proves the DEM simulation parameters are reliable.