a frame extending over a width in an X-axis direction, a length in a Y-axis direction, and a height in a z-axis direction;

a plurality of support wheels rotatably coupled with the frame and configured to support the frame above an underlying ground surface in at least a first state of adjustment of the towable tool apparatus; and

a plurality of ground-working discs each including a concave face surface extending radially outward from an axis of rotation and each being rotatably coupled with a respective rigid shank, each rigid shank being received in a respective receptacle of the frame and retained therein by a respective fastener such that each concave face surface of a first set of the ground-working discs is oriented in a first forward-facing direction offset from the Y-axis direction and each concave face surface of a second set of the ground-working discs is oriented in a second forward-facing direction offset from the Y-axis direction, the first forward-facing direction being different than the second forward-facing direction;

wherein the towable tool apparatus has a mass of between 350 kg and 550 kg, the plurality of ground-working discs consists of six discs.