Design Optimisation and Anti-Adhesion Mechanism Analysis of a Zonally Coupled Biomimetic Plough Surface in a Maize-Root–Loessal-Soil Environment

Residual maize roots alter soil adhesion and tillage resistance in wet loessal soil. A zoned, coupled biomimetic plough surface was developed by combining a shark shield-scale-inspired serrated structure (SSS) on the ploughshare with an antlion-inspired spherical convex hull structure (SCH) on the mouldboard. A coupled soil–root–plough DEM model incorporated Hertz–Mindlin with JKR and bonding contact models and a flexible root model. A Box–Behnken design optimized SCH height, lateral spacing, and longitudinal spacing using soil adhesion mass and tillage resistance as responses. Both regression models were highly significant (p < 0.0001), with R2 values of 0.9873 and 0.9861, respectively. The selected dimensions were 14, 17, and 14 mm. In the DEM surface-configuration comparison, the coupled structure reduced simulated adhesion mass by 69.30% relative to the smooth baseline, with the SCH providing the dominant anti-adhesion contribution. In a separate simulated root-condition comparison, the biomimetic surface reduced adhesion mass by 49.89% in root-free soil and 56.96% in root-containing soil relative to the corresponding smooth-surface treatments. For the same surface configuration, root inclusion reduced adhesion but increased tillage resistance. The optimized design increased the simulated soil-disturbance cross-sectional area by 5.3% and the number of broken interparticle bonds from 5.32 × 105 to 6.03 × 105. Soil-bin experiments at a soil water content of 16 ± 1% and a tillage depth of 250 mm measured reductions of 59.80% in adhesion mass and 12.20% in mean tillage resistance relative to the smooth surface.