The seeder (1) has a chassis (4) resting on ground by wheels (5) and carrying grain implantation elements (7). The wheels are equipped in a work zone of an exterior implantation element (13). A bulged disk (18) is inclined with respect to a vertical direction and is freely rotated in an oblique position with respect to a forward direction during operation. The disk is arranged behind one of the wheels such that the disk is partially extended above the corresponding wheel. The disk is rotatably mounted on an arm (19), where the arm is directly or indirectly suspended with the chassis.
