Study the effects of mouldboard plough surface design parameters on straw burying rate in a specific soil layer: DEM simulation and experimental validation

• A discrete element interaction model of the soil–straw–plough surface was calibrated and established. • The effects of mouldboard surface structural parameters on the motion characteristics of maize straw were investigated. • By adjusting the geometric parameters of the plough surface, the force balance was optimized, achieving precise distribution of straw at the target depth. • Plough surface parameters were optimized by DEM and validated in soil bin tests. Straw return is an effective measure for ensuring food security and promoting sustainable development. However, during the return process, issues persist where straw fails to reach an appropriate decomposition depth, resulting in low utilization rates. For this reason, this paper has designed a plough surface that facilitates the decomposition of straw. A single-factor experiment was conducted using the guide curve opening l , the maximum generatrix angle α , and the tangent angle between the ends of the guide curve ω , with the overall straw burying rate and straw burying rate in the 100–200 mm soil layer as response indicators, to analyse their effects on the indicators and straw motion path. The optimal parameters were determined from the Box-Behnken central composite optimization experiment as l = 318.13 mm, α = 54.925°, and ω = 114° Soil bin tests showed that the optimized plough surface achieved the overall straw burying rate of 89.93 % and the straw burying rate in the 100–200 mm soil layer of 42.8 %, representing improvements of 2.26 % and 8.24 %, respectively, compared with the conventional mouldboard surface. This result also validates the effectiveness of simulation experiments. This paper provides insights for promoting straw return measures and offers new research methodologies for developing precision straw return machinery.