关键词: 毛乌素沙地, 飞播植被, 现状, 评价

Abstract: Among the plant species used for air-seeding on the moving sands in Mu Us Sandy Land, Hedysarum laeve, with the fast root growth during sapling period and effective propagation from subterraneous root, can rapidly expand the colonizing range and makes sand surface fixed. Artemisia sphaerocephala has higher sapling density and can stabilize sand surface in certain period, thus creates a stable growth site for other species. Hedysarum scoparium, a pioneer plant on psammosere in desert zone, can adapt the ecological environment of moving sands. But because of its sparse growth habit, it is always scattered in seeding areas with lower density. As for its inferior ability of sand stabilization it is not an ideal air-seeding species.On the basis of the dune developed degrees, the seeding areas in Mu Us Sandy Land can be divided into 4 categories. In gentle dune areas with dune height below 5 meters and dune density between 0.6 and 0.7 and barchan dunes as the dominant dune shape, the air-seeding plants can rapidly occupy the whole seeding area and the moving dunes can be totally fixed after seeding. When dune height is 5~10 meters and dune density from 0.7 to 0.8 and barchan chain is the main dune shape or it co-exists with check dunes, following seeding the saplings firstly colonize the bottomlands and the middle and lower parts of dunes, and then gradually extend the range, the whole seeding area can finally be occupied by plants except very few higher dunes. When dune height is over 10 meters and dune density over 0.8, and check dune is dominant dune shape, the saplings can only colonize the bottomlands and the lower part of dunes, and it is very hard for air-seeding plants to expand their colonizing range due to the harsh existing condition; this kind of seeding area can reach semi-fixed level at most after air-seeding. The fourth kind of air-seeding areas is partial flimsy sand covered loess, occasionally dune developed with lower density, generally below 0.5. This kind of seeding areas has also very good seeding effects.