Abstract: Agriophyllum squarrosum, Artemisia sphaerocephala and Artemisia ordosica are the dominant plant species at different stages of vegetation succession in the southern Tengger Desert. A fieldpot experiment was conducted at Wuwei Station for Desert Control Research in summer 2009. Response of the seedling emergence rates of the 3 species to two soil types (sand and sandy loam) and seven sand burial depths (0, 1, 2, 3, 4, 6 cm and 8 cm) was measured. Seedling emergence rate of A. squarrosum seeds buried at 0 cm in sand was the lowest, that of the 3 species seeds buried at 1 and 2 cm in sand was the highest, and that of the 3 species seeds buried in sandy loam was lower than that in sand. The optimal burial depth for seedling emergence of A. squarrosum and A. ordosica was decreased from 2 cm in sand to 1 cm in sandy loam. In sand, A. squarrosum seeds at all sand burial depths emerged, the seedling emergence rate was high, and the seedling mortality rate was low; thus, A. squarrosum could be the dominant species for sand dunes. In sandy loam, however, the emergence speed of A. squarrosum seeds at sand burial depths of 0-4 cm was slow, and the seedling mortality rate was higher than that of other two species. Thus, A. sphaerocephala and A. squarrosum replaced A. squarrosum on fixed and semifixed dunes at the seeding stage.

Key words: soil type, sand burial depth, seed, seedling emergence rate, mortality rate, Tengger Desert