Provided is a combination of a tractor and a implement drawn by the tractor by way of a draw bar, supported on the ground by wheels, the implement having a processing element interacting with a field. A controller is connected to a first actuator disposed for adjusting the angle between the draw bar and the implement, and to a second actuator disposed for adjusting the angle of the wheels of the implement about the vertical axis. The controller can be operated for actuating the two actuators in such a manner that the longitudinal axis of the processing element is always oriented at least nearly orthogonal to a target line.
