Design and Experiment of Profiling Furrow-Ridge Terrain by Cane Leaf-Chopping and Returning Machine

Conventional straw-returning machines were incompatible with ridge cultivation terrain and unevenly distributed materials, resulting in substandard operations such as insufficient leaf fragmentation, damage to ratoon stumps, and high cutting energy consumption. In this regard, this paper proposes a novel profiling configuration of chopping and returning machine to adapt to the coverage characteristics of cane leaves in furrow-ridge terrain. The leaves piled at furrow sole are intensively collected and fed into the whirling space by the flexible hook teeth assembly, and are cooperatively broken by the unequal-length swing blades densely arranged along the double helix. Based on the measured topographic trends and dynamic analysis of the leaf-shredding process, experimental factors affecting profiling cutting and picking capabilities of the main components were determined. Further, using chopping qualification rate (CQR) and fragmentation degree (CFD) as indicators, field trails were conducted through a response surface method to test the comprehensive crushing performance of the machine. After multi-objective optimization, the optimal structural and operating parameters were determined as: blade length gradient of 1.57 cm, teeth spacing of 6.84 cm and feed speed of 3.2 km/h. With such adaptive configurations, CQR and CFD reached 81.14% and 0.101, respectively, which were significantly improved by 60.50% and 47.99% compared to those of conventional machines. Crushed leaves appeared to be more thoroughly mixed with the soil and more evenly spread in the field. Meanwhile, the traction resistance tended to be stable, with an effective RSM 45.85% lower than the value of higher-level blade gradient, indicating a better overall fit with the irregular terrain. This study can provide a reference for the development of leaf-chopping and returning machines suitable for ridge-type crops.