The effect of various edge-curve types of plain-straight blades for strip tillage seeding on torque and soil disturbance using DEM

Abstract

Strip tillage seeders have shown great advantages in seedbed preparation and residue handling in no and minimum tillage seeding. However, soil disturbance and torque requirements need to be further reduced. To address this issue, the simulation in this study used the discrete element method (DEM) to examine the effect of different edge-curve geometries on torque requirements and soil disturbance characteristics. Herein, the edge-curve geometries include three types of plain-straight blades (Archimedean spiral, logarithmic spiral, and sinusoidal-exponential spiral blades) with four slide-cutting angles of edge-curve tip (30°, 40°, 50°, and 60°). The model particle (i.e., ball-ball) stiffness kn was calibrated through a soil bin test, and the optimum value was 6 × 103 N/m. The results showed that the blade rotation angle varied with respect to the slide-cutting angle of the edge-curve tip when the soil cutting started and the peak value occurred: the larger the slide-cutting angle was, the earlier the soil cutting began and the peak value appeared. Among the three edge-curve types, the Archimedean spiral blade (which had the largest average slide-cutting angle) obtained the highest average torque and the largest number of soil particles thrown upward, whereas the sinusoidal-exponential spiral blade (which had the smallest average slide-cutting angle) obtained the lowest values in both metrics. As the slide-cutting angle of the edge-curve tip increased, the average torque requirement decreased and fewer soil particles were thrown upward, indicating that a larger slide-cutting angle was preferred when less soil disturbance was desired.