The forage harvester is mounted with a front-mounted implement such as a pick-up or a corn head, and chopping blades (29) arranged in the cutting-drum (1). The feed-rolls (2,2,3,3) are hydrostatically driven in the upstream direction of crop flow direction (30), using a hydraulic motor (13). The mechanical drive of the cutting-drum is coupled with a hydraulic pump (12) which is used as a hydrostatic pressure source of the hydraulic motor for driving the feed-rolls and as a hydraulic motor for reversing the cutting-drum. An independent claim is included for operating apparatus of forage harvester of agricultural crops.
