1·So small tractors fitted with iron wheel with lugs can improve tractive and appendiculate performance of tractor in dry land.
表明小型轮式拖拉机叶轮与胶轮并装可提高旱地作业，特别是重负荷作业时的牵引附着性能。
2·For several decades, a lot of research work have been done by many scholars and experts to improve tractors tractive and appendiculate performance and many achievements have been obtained.
近几十年来，国内外许多学者、专家对如何提高拖拉机的牵引附着性能作了大量的工作，取得了较好的效果。