The seed covering system comprises a support structure (39) which is fixed to the seeder. An arm (40) is connected to the support structure by a pivot (41). A carrying structure (42) extending transverse to the forward working direction (20) is connected to the arms by a second pivot (43). Seed covering tools (44) are fixed to the carrying structure. A first adjustment member (85) enables adjusting of the angle of inclination of the covering tools. A second adjuster (130) enables bringing together or distancing the covering tools from the support structure. The assembly of arms, carrying structure and covering tools is retractable by sliding in the forward direction so as to reduce the obstruction during transportation. Each support structure has two webs (46,46') extending parallel to the forward direction which form a cover (47) between which corresponding arm extends. Each support structure has a roller with a horizontal axis perpendicular to the forward direction , on which the corresponding arm slides during retraction or positioning of the covering system.
