Design, Prototype Development, and Operating Parameter Optimization of a PTO Driven Pneumatic Safflower (Carthamus tinctorius L.) Floret Harvester

A vacuum-assisted, field-type safflower floret harvester was designed, prototyped, and evaluated under both bench and field conditions. The system was developed specifically for the selective harvesting of safflower florets and is not intended for seed harvesting, which is typically performed using combine harvesters. The system consists of a centrifugal fan, cyclone separator, hydraulic drive unit, and a three-head picking mechanism. Bench tests quantified pressure, air velocity, and torque at critical system points. Field experiments were conducted using a 3 × 3 factorial design with working widths of 0.17, 0.15, and 0.12 m and forward speeds of 0.70, 1.08, and 1.80 km h⁻¹. Measured air velocities confirmed effective material capture, ranging from 46–72 m s⁻¹ at the fan outlet, 30–61 m s⁻¹ at the top head, and 9–13 m s⁻¹ at the cyclone inlet. The highest field and product capacities (0.369 da h⁻¹ and 3.69 kg h⁻¹) were obtained at 0.17 m and 0.15 m working widths combined with 1.80 km h⁻¹ forward speed. The highest yield (7.37 kg da⁻¹) with the lowest loss (26.13%) occurred at 0.15 m working width and 0.70 km h⁻¹ forward speed. The most favorable fuel consumption and impurity ratios were achieved at a working width of 0.17 m and a forward speed of 1.80 km h⁻¹ (9.57 L da⁻¹ and 11.79%, respectively). Analysis of variance revealed the significant effects (P<0.01) of working width, forward speed, and their interaction on performance parameters. An operation at 0.15 m working width and 0.70 km h⁻¹ forward speed, with PTO ≈ 350 rpm, was identified as optimal for quality-oriented harvesting, whereas 0.17 m working width and 1.80 km h⁻¹ forward speed at PTO 350–450 rpm was suitable for throughput-oriented operation. During an eight-hour shift with a single operator, the system can achieve up to 30 kg of output, substantially exceeding the output of manual or backpack harvesting methods. The principal contribution of this study is the development and field validation of a tractor-mounted pneumatic harvesting system optimized for safflower floret collection, providing a scalable mechanization alternative while maintaining acceptable impurity and loss levels. Performance was strongly influenced by header geometry and forward speed. Scalability may be further enhanced through multi-head configurations and automated header positioning. These findings demonstrate that the presented engineering framework contributes to the development of field-scale pneumatic harvesting systems for lightweight specialty crops with similar aerodynamic and mechanical characteristics.