A robotic weeding-hilling system for ridge-cultivated tobacco: Preserving industrial leaf quality through integrated root zone management

The economic value of industrial tobacco ( Nicotiana tabacum L.) depends on both leaf structural integrity and chemical consistency. Consequently, minimizing mechanical injury during cultivation is critical for maintaining premium industrial grades. Current robotic weeding technologies are optimized for efficiency but often neglect vital agronomic requirements. Notably, they lack mechanisms to safeguard fragile basal leaves and provide mandatory hilling-a process crucial for root-zone management and the preservation of industrial leaf quality. To bridge this gap, we propose an agronomy-centric robotics paradigm that transcends simple weed suppression. We developed a precision system featuring an oscillating end-effector that generates a diamond-shaped kinematic trajectory, enabling concurrent intra-row to weed shearing and active root-zone reconstruction. The system utilizes a YOLOv8-based RGB-D vision module to enforce a dynamic 3D protection zone. Field trials validated that at an optimal forward speed of 0.24 m/s, the robot achieved an 85.53% weeding rate while restricting crop injury to 1.86%-well below the critical industrial damage threshold. Furthermore, by minimizing mechanical injury, this precision approach preserves the morphological integrity of the crop base. This structural preservation minimizes immediate physical trauma and creates a favorable mechanical soil environment, which has the potential to facilitate root-zone management and support subsequent crop development. Our cost-benefit analysis indicates that for high-value industrial crops, the financial premium preserved through minimizing mechanical leaf injury provides a favorable trade-off against this relatively slow operational speed. This study establishes that agronomy-integrated robotics can serve as an important quality-control instrument, providing a chemical-free pathway to satisfy stringent international market grades and residue standards.