A soil cultivating apparatus including a tractor towing a row cultivator by means of a three-point linkage. The row cultivator includes a fixed portion and a moveable portion having soil scarifying tools. The movable portion is laterally moveable relative to the fixed portion by means of linkages and is effected by a hydraulic actuator under control of tool bar control systems which is able to determine the position of the moveable portion relative to the fixed portion by means of a sensor. Mounted upon the moveable potion is a DGPS antenna GPS receiver that forms part of the control system. The control system has a microprocessor which operatively executes a stored program. The microprocessor receives data from an intra-rig sensor and from the GPS receiver specifying the absolute coordinate of the movable portion relative to the earth. On the basis of the data received and in accordance with the instructions in the program, the microprocessor generates a series of lateral motion commands which controls the hydraulic actuator. An operator of the system may enter coordinates defining a desired line of the movable portion by means of a data entry device. Command prompts and other feedback to the operator are displayed by means of a screen.