Two-Stage Spraying with Leaf-Turning Mechanism for Enhanced Coverage and Reduced Chemical Use

Spraying agricultural chemicals is vital for maintaining crop yield and quality; however, it comes with its own set of challenges such as spray drift and rising costs. Despite advancements in autonomous vehicles that reduce the reliance on manual labor, issues related to pesticide spray volume and spray drift persist in robotic application systems. Hence, efficient spraying technology is essential for the uniform application of pesticides, especially in hedge-trained crops where dense canopies limit access to abaxial surfaces. Although conventional air-assisted spraying systems enhance coverage through high-velocity airflow and spray pressure, there is a practical limit to the spray volume reduction as insufficient spray volume can reduce penetration into dense and complex canopies. In this study, we propose a novel tractor-mounted two-stage spraying system with a leaf-turning mechanism designed for hedge-trained crops, targeting both adaxial and abaxial surfaces. Experiments were conducted under controlled laboratory conditions and real vineyard conditions, and the results showed that the proposed spraying system used only 60% of the spray volume compared with a conventional air-assisted spraying system, while achieving equivalent coverage on adaxial surfaces and a 6% improvement in coverage on abaxial surfaces. These findings suggest that the proposed spraying system can reduce spray drift while maintaining or improving spraying performance, primarily due to the reduced spray volume, minimized air–pesticide-droplet interactions, lower operating pressure, and limited air assistance range.