A control member (12), manually activatable by a switch, is connected between the fertilizing machine (2) and the fertilizer distribution linkage (4). A steering angle sensor detects the steering angle of the machine or its wheels (5). An on-board computer (11), mounted to a tractor (1), receives the detected steering angle and operates the control member, which in turn makes the linkage horizontal and perpendicular to the machine driving direction. A hitch bar (6) tows the machine to the back of the tractor.
