1. A method of reducing a large mass of crop material including the steps of: engaging an upstanding crop mass from beneath the latter with a horizontally moving conveying force to advance the mass in the direction of movement of said conveying force; continuing said advancement of the mass using said conveying force only as the mass is progressively delivered into the mechanism for shredding the same; passing said mass over a standby source of swingable lifting force on the way to said mechanism; and after shredding most of the original mass using said conveying force only, restraining the remaining portion of the upstanding mass against tipover and feeding the same into the mechanism using said swingable lifting force only.