An agricultural implement with ground-engaging implements tracks in a direction down slope when pulled by a traction vehicle over uneven, or sloped, terrain. The implement's path from the track of the vehicle depends upon, among other things, the slope of the terrain. To compensate for this tendency to drift down slope away from the pulling vehicle's track, the implement frame is provide with controllable forward and aft pivoting wing sections to which the ground engaging implements are attached. Using a GPS receiver, precise positioning information is used to position the wing sections so that the ground engaging members are directed up slope to move the implement's track upwardly in correcting its track, with the wing sections then automatically re -positioned when the implements are on the proper track.