A tillage implement has gang assemblies of rotatable tillage tools that can be angle-adjusted from the seat of the towing tractor using hydraulic actuators. The tillage tools may comprise generally flat, wavy coulter blades or the like so that the machine may be set up for vertical tillage with the coulters aligned at a zero degree angle with the path of travel of the implement or for residue management operations with the coulters maintained at an oblique angle of up to ten degrees relative to the path of travel. A six degree angle is preferred for the residue management position. A master-slave hydraulic flow arrangement for the actuators assures simultaneous actuation, while mechanical synchronizing apparatus between the two front gang assemblies on the center frame section of the machine assures synchronized movement of those assemblies. Mechanical motion-transmitting mechanism transmits the hydraulically powered adjusting movement of the front gang assemblies to the rear gang assemblies.