INFLUENCE OF DIFFERENT LONGITUDINAL DUNE POSITIONS IN THE GURBANTUNGGUT DESERT ON THE REPRODUCTION OF HALOXYLON AMMODENDRON SEEDLINGS

Field observations have been conducted on the survival mechanism of Haloxylon ammodendron seedlings in different longitudinal dune positions in the Gurbantunggut Desert for six consecutive years. In addition, the relationship between seedling settlement and environmental factors has been analyzed. Haloxylon ammodendron seedlings on windward slopes exhibit good natural reproduction, which is significantly higher than those on dune crests and leeward slopes (P=0.002). Wind erosion and sand burial impose restrictions on the natural production of Haloxylon ammodendron seedlings on dune crests and leeward slopes. Soil water content is the most important factor that influences the survival of seedlings. The other factors are herbaceous coverage, accumulated temperature at 30 cm aboveground from April to June, and vapor pressure deficit. Seedlings planted artificially and through afforestation can better adapt to wind erosion and sand burial. The average preserving rates of seedlings on windward slopes, leeward slopes, and dune crests are 35.67%, 29.6%, and 32.44%, respectively, which are significantly higher than that of naturally reproduced Haloxylon ammodendron seedlings (P<0.01). In afforestation, snow entropy combined with a water-retaining agent is applied during spring on 2-year-old seedlings artificially planted on dune crests and leeward slopes to increase the survival rate of seedlings.