EFFECT OF WATER SUPPLY AND SOWING DEPTH ON SEEDLING EMERGENCE IN TWO HALOXYLON SPECIES IN THE JUNGAR BASIN

Haloxylon ammodendron and H. persicum are important part of the desert ecosystems, particularly in shifting sand dune areas, and these plants are common in the Jungar Basin of the northwestern China. To obtain basic information for the conservation and reintroduction of these two species, we studied the impact of water supply and sowing depth on the seedling emergence. Our results showed that proportion and rate of emergence increased with quantity of irrigation rate and sowing depth initially and then it declined, leading to the seedling mortality. Seeds, which were sown for 0.5 cm or 1.0 cm depth and having 20 mm of water supply, resulted in the highest emergence percentage and rate, whereas surface sowing of 0 cm depth and 10 mm of water supply led to 100% of seedling mortality within 30 days. Based on these results and taking into account the pattern of precipitation in the Jungar Basin, sowing of H. ammodendron and H. persicum for 0.5-1.0 cm depth before the snow cover begins melting in early spring is a critical point for the artificial restoration of these plants.