Abstract: A harvesting machine includes at least one drum rotatable about an upright axis and open at the bottom, an effective skirt secured to a lower part of the drum, including a first skirt substantially in the shape of a hollow truncated cone, and a second skirt secured to the first skirt and extending therebelow, so that only the second skirt makes operative contact with the ground, at least near the front of the harvesting machine as defined by the forward direction of its movement.