Effects of water supply and sand burial on seed germination and seedling emergence of three sand-fixing Artemisia plants in Horqin Sandy Land

Semi-shrubs, Artemisia wudanica, A. halodendron and A. sphaerocephala, are major sand-fixing plants in Horqin Sandy Land. A. wudanica is a native pioneer species growing in shifting, semi-shifting sandy land and A. halodendron is the dominant species in semi-shifting, semi-fixed and fixed sand dunes. A. sphaerocephala, sown by aerial seeding to Horqin, was imported from Qubqi Desert and Mu Us Sandy Land as a sand-fixing pioneer plant. In this study, five sand burial depths and four water supply levels were adopted to investigate the responses of three plants to sand burial and water supply during seedling emergence. Water treatments are equivalent to mean monthly precipitation of 25, 50, 75 and 100 mm, respectively, and the average monthly precipitation during grass germination period in the study area is about 50 mm. According to the results, rainfall deficiency led to regeneration difficulty for A. wudanica, water stress combined with competition with aerial seeding plants, A. wudanica populations degraded in Horqin Sandy Land.