Rotary tillage, ridging, and mulching are commonly used cultivation methods for crops such as chili peppers, tomatoes, and strawberries in the arid regions of Northwest China. An integrated machine for rotary tillage, ridging, and mulching was designed by considering the growth characteristics of pepper root systems and the agronomic requirements of ridge beds. The structural parameters and their value ranges for key components such as the rotary tillage device and the ridging device were determined. By introducing the Bonding contact parameter, the soil cohesion between soil particles during the process of rotary tillage and ridging can be simulated. A coupled simulation model using the Discrete Element Method (DEM) and Multibody Dynamics (MBD) is established. The experimental factors selected were rotary tillage depth, ridging roller speed, and machine forward speed. The evaluation indexes were the traction resistance of the stemming roller and the soil compactness of the ridges. A response surface Box–Behnken Design test was carried out to obtain the best working parameters of the rotary tillage and ridging process for chili pepper cultivation as follows: the rotary tillage depth was 176 mm, the ridging roller speed was 283.71 r/min, and the machine forward speed was 0.55 m/s. Field experiments with optimal parameters showed that the ridge top width was 549.2 mm, the ridge bottom width was 750.5 mm, the ridge height was 222.9 mm, the ridge spacing was 1173.1 mm, the surface smoothness of the ridge was 12.3 mm, the width of soil covering the film edge was 76.3 mm, the stability coefficients of the ridge size parameters were all above 91.73%, and the soil compactness after operation was 60.82 KPa. All indicators meet the requirements for the rotary tillage and ridging cultivation of chili peppers in arid regions, providing reference for the design of rotary tillage and ridging mulching implements and the development of sustainable agriculture.
Wood-plastic composites are being widely used more and more, and the bonding strength between fillers and matrix is an important factor affecting the properties of wood-plastic composites. In this study, rapeseed straw and rapeseed stalk were pretreated with sodium hydroxide and then filled with polyvinyl chloride matrix to prepare composites. The chemical composition, thermal stability, microstructure, physical properties, mechanical properties, and abrasive wear resistance of the composites were characterized, and the effects of different concentrations of alkaline treatment on rapeseed straw composite and rapeseed stalk composite were revealed. The results show that alkaline treatment has no significant effect on the chemical composition of the composites but has an obvious effect on other properties. Among them, after 1% alkaline treatment, rapeseed straw composite has the highest hardness, thermal stability, and impact strength, rapeseed stalk composite has the highest impact strength and bending strength. After 3% alkaline treatment, rapeseed straw composite has more wear resistance, rapeseed stalk composite has the highest density, the highest tensile strength, and more wear resistance. The rapeseed straw composite with 5% alkaline treatment has the highest density, and the rapeseed stalk composite with 7% alkaline treatment has the highest thermal stability. The hardness of rapeseed stalk composite and the tensile strength and bending strength of rapeseed straw composite decreased with the increase of alkaline treatment concentration.