An agricultural implement for clearing and tilling soil to be planted includes a residue-clearing sub-assembly including a first rotatable coulter wheel and at least one toothed wheel mounted for rotation about an axis located rearwardly of the axis of rotation of the first coulter wheel of forward portion of the toothed wheel overlaps a rear portion of the first coulter wheel. A tillage sub-assembly includes second and third coulter wheels that are offset from each other both laterally and fore and aft, and are mounted for rotation about axes of rotation that are located rearwardly of the axes of rotation of the toothed wheels. A depth control device is mounted for rotation about an axis of rotation located rearwardly of the axis of rotation of the rearmost of the second and third coulter wheels. A common frame carries the residue-clearing sub-assembly, the tillage sub-assembly, and the depth control device so that all of the axes of rotation are fixed relative to each other. An adjustable linkage is attached to the frame for allowing flotation of the unit on a contour.