Abstract: A support frame is provided for support from the three point hitch of a tractor and rotatably journals an elongated horizontal roll for rotation about an axis extending transversely of the support frame. The support frame includes opposite side ground skid portions and the roll has its lower periphery elevated slightly above the under surfaces of the ground skid portions. Although other structure may be provided for driving the roll, a forwardly directed swing arm is pivotally supported from the support frame at its rear end and rotatably journals a ground engageable drive wheel at its forward end. The roll is journalled for rotation about an axis coinciding with the axis of oscillation of the support arm and the drive wheel is drivingly coupled to the roll for rotating the latter in a direction opposite to the direction of rotation of the drive wheel and at a peripheral speed which is at least substantially equal to the peripheral speed of the ground wheel.