COMPARISON OF TWO SUBSOILER DESIGNS USING THE DISCRETE ELEMENT METHOD (DEM)

Subsoiling is an essential tillage practice for loosening soil and enhancing water infiltration. In this study, a discrete element model was developed and validated to simulate soil-tool interactions. The validated model was then used to evaluate two design alternatives of subsoiling tool: a non-winged tool (NW) and a winged tool (WW). The performance indicators used for the evaluation included draft force and soil disturbance area at different rake angles (ranging from 23.0 degrees to 40.5 degrees) and working depths (ranging from 225 to 350 mm) at a constant travel speed of 0.8 m s(-1). The results showed that the WW tool required more than twice the draft force and disturbed more than twice the soil area when compared to the NW tool, regardless of rake angle and working depth. The draft force of the NW tool had no variation over the range of rake angles tested, whereas the WW tool had the lowest draft force at 26.5 degrees. The soil disturbance area did not show any particular trend for both design alternatives at the rake angles studied. With the increase in working depth, the soil disturbance area of the WW tool decreased; however, no change was observed for the NW tool. Considering both draft force and soil disturbance area, both the NW and WW tools should be operated at the shallowest possible depth, and the recommended rake angle was 33.5 degrees for the NW tool and 33.5 degrees to 40.5 degrees for the WW tool.