In the cotton fields in Xinjiang, residual film is present in the soil for a long period of time, leading to a decrease in the tensile strength of the residual film and increasing the difficulty of recycling. Existing technologies for residual film recovery focus on mechanical properties and ignore the dragging and tearing of residual film by cotton stubble. The effect of cotton straw–root stubble on residual film recovery can only be better determined by appropriate machine operating parameters, which are essential to improving residual film recovery. Through analyses of the pickup device, key parameters were identified, and a model was built by combining the FEM and SPH algorithms to simulate the interaction of nail teeth, residual film, soil and root stubble. The simulation revealed the force change law of residual film in root stubble-containing soil and the influence of root stubble. By simulating the changes in the characteristics of the residual film during the process, the optimum operating parameters for the nail teeth were determined: a forward speed of 1849.57 mm/s, a rotational speed of 5.5 r/s and a soil penetration angle of 30°. Under these optimized conditions, the maximum shear strain, pickup height (maximum deformation) and average peak stress of the residual film were 1293, 363.81 mm and 3.42 MPa, respectively. Subsequently, field trials were conducted to verify the change in the impact of the nail teeth at the optimized speed on the recovery of residual film in plots containing root stubble. The results demonstrated that when the root stubble height was 5–8 cm, the residual film averaged a recovery rate of 89.59%, with a dragging rate of only 4.10% at crossings. In contrast, 8–14 cm stubble plots showed an 82.86% average recovery and an 11.91% dragging rate. In plots with a root stubble height of 5–8 cm, compared with plots with a root stubble height of 8–14 cm, the recovery rate increased by 6.73%, and the dragging rate of residual film on root stubble decreased by 7.81%. The percentage of entangled residual film out of the total unrecovered film was 30.10% lower in the 5–8 cm stubble plots than in the 8–14 cm stubble plots. It was confirmed that the effect of cotton root stubble on residual film recovery could be reduced under appropriate machine operating parameters. This provides strong support and a theoretical and practical basis for future research on the correlation between root stubble and residual film and how to improve the residual film recovery rate.

To address the problems of excessive transportation width, limited operational flexibility, and insufficient adaptability to uneven seedbed conditions of wide-width cotton film-mulching seeders, this study designed a horizontal-folding cotton wide-width film-mulching seeder. The overall structure and operating principle of the machine are described, and the results of theoretical analyses conducted on the key components, including the folding frame, parallel four-bar profiling mechanism, and hydraulic system, to determine their critical structural parameters are reported. The static and modal characteristics of the folding frame under road transportation conditions were investigated using the finite element analysis method. Under the fully loaded condition, the maximum stress of the folding frame was 102.52 MPa, and the maximum deformation was 1.7857 mm. The first six natural frequencies of the folding frame ranged from 15.734 to 39.681 Hz. The modal analysis results indicate that the natural frequencies of the folding frame are separated from the main excitation frequencies considered in this study, suggesting a low resonance risk under the investigated operating conditions. An ANSYS–ADAMS rigid–flexible coupled model of the folding frame was established to analyze its dynamic behavior during field operation. The location of the maximum loading point of the folding frame and the stress variation curves of the rocker arm during operation were obtained. The maximum load at the hinged joint between the driving rocker arm and the suspension frame was 4.27 × 10⁴ N, while the maximum loads at the middle position of the driving rocker arm and the hinged joint between the driving rocker arm and the auxiliary frame were 2.78 × 10⁴ N and 1.48 × 10⁴ N, respectively. Using a multi-channel strain signal acquisition system, the stress variations at critical points of the folding frame under field deployment operation conditions were experimentally measured. The finite element analysis results were compared with the experimental measurements. The results showed that under both road transportation and field operation conditions, the stress variation trends obtained from the experimental measurements were consistent with those from the finite element analysis, verifying the reliability of the folding frame. Field test results indicated that the folding cotton wide-width film-mulching seeder achieved a missing-hole rate of 2.28%, a single-seed rate of 95.7%, a qualified hole spacing rate of 97.12%, a damage rate of 0.11%, a qualified rate of seeding depth beneath the plastic film of 95.86%, a longitudinal elongation rate of the plastic film of 5.17%, a qualified rate of light-exposure surface width of 91.64%, a plastic film light-exposure surface flattening rate of 98.88%, a qualified rate of soil-covering thickness at the film edge of 95.94%, and a qualified rate of soil-covering width at the film edge of 97.74%. All measured performance indicators met the requirements of relevant national and industrial standards.