A harvesting system for collecting crop grain crop residue in a single pass with a baler towed by a combine harvester is provided. The system includes a hydraulic system that hydraulically interconnects the combine harvester with the baler, allowing the engine of the combine harvester to hydraulically power systems and components of both the combine harvester and the baler. The hydraulic system may include a combine hydraulic system and a baler hydraulic system which may be hydraulically connected through multiple interconnections for hydraulically powering different functions of the baler using hydraulic pressure that is generated at the combine harvester. A first combine-to-baler hydraulic interconnection may transfer hydraulic power from a combine primary baler drive hydraulic circuit to a baler drive hydraulic circuit. A second combine-to-baler hydraulic interconnection may transfer hydraulic power from a combine spreader hydraulic circuit to a baler conveyor and/or auxiliary hydraulic.