Discrete element simulations and experiments of soil disturbance as affected by the tine spacing of subsoiler

Tine spacing is a key parameter for the design of a subsoiler and has a significant effect on soil disturbance, which is a critical performance indicator of subsoiling. In this study, a subsoiling model was developed using the discrete element method (DEM). A subsoiling experiment was also conducted in a field with a loamy clay soil to serve the model development and model validations. In both the simulation and experiment, two V-shaped subsoiling tines were investigated at five different tine spacings (300, 350, 400, 450, and 500 mm), a constant working speed (0.83 m s−1) and a constant working depth (300 mm). The results showed that the 400 mm tine spacing resulted in the highest particle forces in the middle and deep soil layers. The height of the unloosened soil between two adjacent subsoilers increased as tine spacing increased. When the tine spacing was varied from 300 to 500 mm, the undisturbed soil height was changed from 100 to 226 mm in the experiment, and from 79 to 170 mm in the modelling. When the tine spacing was 400 mm, the number of soil particles disturbed in the shallow soil layer accounted for 45.6% of the total soil particles disturbed, which was the least among all the tine spacings. Considering the characteristics of soil disturbance, the tine spacing of 400 mm appeared to outperform the other spacings.