Codonopsis pilosula is cultivated mainly in sandy soils, especially in the Dingxi area of the Gansu province, northwest China. They are mainly planted in hilly areas, where large machines cannot reach easily. Codonopsis pilosula transplanting has been adopted with a conventional flat planting way, film mulching and seedling outcrops. While its planting requires opening a shallow ditch, short operation cycle, considerable labor intensity and is in large demand, a simulation analysis was performed according to specific tillage resistance, helpful in the optimization design in later stages and the improvement of a domestic ditching plow’s performance. This paper studies the simulation performance of an adjustable trench plough and analyzes the orthogonal test and Design-Expert response surface of the data. EDEM simulation software was used to analyze the traction resistance of the furrow ditching mechanism in the ditching process. The results show that the traction resistance increased from 1751.31 N to 2197.31 N as the simulation working speed increased from 0.9 m/s to 1.5 m/s, 1.25 times higher than the former. It indicates that speed had significant effects on traction resistance. With the increase in working speed, the furrow traction resistance and specific consumed power were increased considerably. Using the stability coefficient of the ditching depth and consistency coefficient of ditching bottom width as test indices, speed and angle of furrowing as impact factors, Box–Behnken orthogonal experiment design method, and establishing test indices and test factors, the regression model between the analysis of the influence of the test index, comprehensive agronomic requirements and MATLAB factor optimization of the experiment, the optimized operation parameter combination was obtained: the forward speed was 0.9 m/s, the angle of ditching was 35° and the stability coefficient of the ditching depth and consistency coefficient of ditch bottom width were 97.57% and 98.03%, respectively. The data after the simulation comparison test can provide a design reference for the domestic small trench operation.

To solve the problems of high temperature and drought in the Xinjiang Turpan area and the low survival rate of melon seedlings transplanted into dry soil, existing transplanters for large plant type young melon seedlings can be mechanized. For non-destructive planting for small plant types, such as Hami melon seedlings, there are still poor transplanting effects, planting point precise pile-soil, and other problems. In this study, a water transplanter for laying pipe and film for Hami melons was designed to mechanize the operation of rotating tillage, laying film and covering soil, transplanting potted seedlings on film, and water injection of the seedling root and planting hole, and soil piling and suppression. In this study, a transplanter was designed by coupling the motion of an earth-covering roller and a duck’s mouth planter and realized the precise mound of soil in the planting hole, solved the difficult problem of the precise mound of soil on the membrane, and at the same time carried out water injection on the root of the melon seedlings, which effectively solved the problem of low survival rate of transplanted seedlings in the arid region of Turpan, Xinjiang, China. Field experiments showed that the survival rate of melon seedlings under drip irrigation for 8 h after transplanting into dry soil exceeded 97%. The efficiency of mechanized operation can reach 1 mu/person/hour, which is more than 8 times higher than manual operation. The operation speed of the machine is 1~1.2 m/s, and the qualified transplanting rate is 93.26%, which meets the requirements of cantaloupe transplanting agronomy. This study provides a new method for dry soil cantaloupe transplanting. This article can also provide a design reference for Hami melon transplanting mechanization in arid areas.

CFD simulation and experiment on the flow field of air-assisted ultra-low-volume sprayers in facilities

Design and experiment on atomizer parameter of impinging low-speed centrifugal atomization sprayer

In view of the lack of accurate contact parameters and the difficulty of measuring contact parameters in the discrete element simulation of mechanized harvesting of highland barley, this study took the wax-ripening highland barley as the object, carried out the discrete element simulation of highland barley stem based on EDEM, and calibrated the discrete element simulation parameters of highland barley stem by response surface optimization. In this paper, Plackett-Burman test was used to screen 8 initial parameters. It was found that the static friction coefficient between highland barley stems, the rolling friction coefficient between highland barley stems, and the rolling friction coefficient between highland barley stems and steel plates have significant effects on the particle angle of repose. Based on the optimal value range of significant factors determined by the steepest ascent test, a second-order regression model of the angle of repose and significant parameters was established and optimized based on the results of Box-Behnken test. The optimal parameter combination of significant parameters was obtained as follows: static friction coefficient between highland barley stems is 0.27, rolling friction coefficient between highland barley stems is 0.07, and rolling friction coefficient between highland barley stems and steel is 0.26. Finally, the simulation results under the optimal parameter combination are compared with the actual test angle of repose. The relative error is 0.52 %. That indicates that the parameters of the simulation calibration are credible, which can provide a reference for the future research on the cleaning device in the mechanized harvesting of highland barley.