A wheel assembly for traversing a path along a ground surface having a layer of soil, the wheel assembly comprising a central support and an airless flexible covering mounted on the central support and having a plurality of rigid sections and a plurality of flexible sections. The outwardly protruding spokes urge the rigid sections into the layer of soil when the rigid sections contact the ground surface. The flexible sections flex inwardly when the flexible sections contact the ground surface so that the rigid sections and the flexible sections cooperatively form a corrugated pattern in the ground surface without urging the soil to side margins of the airless flexible covering, the corrugated pattern having a plurality of valleys formed by the rigid sections and a plurality of peaks formed by the flexible sections.