RESPONSE OF HALOXYLON AMMODENDRON (C. A. MEY) TO UNDERGROUND WATER QUALITY, DEPTH AND SOIL SALT DEPOSITION IN GURBANTONGGUT DESERT, WEST CHINA

Abstract

Haloxylon ammodendron degradation in arid regions of China has become a serious and widespread ecological issue. This study attempts to provide theoretical support for achieving the goal of ecological protection and construction as well as its restoration and reconstruction in the desert regions. A three-year research of the groundwater under the western hinterland of Junggar basin in Xinjiang was carried out to analyse groundwater depth, its water quality, soil physicochemical properties and some other characteristics in areas of H. ammodendron degradation. The results reveals that species richness in the region is not directly connected with groundwater level, but negatively correlated with soil conductivity. The research further investigated that groundwater level has no significant effect on the survival of H. ammodendron seedlings. However, there exists a significantly positive correlation between the mortality rate of H. ammodendron seedlings and soil conductivity. The growth of H. ammodendron in the degraded area is affected by both groundwater level and its water quality. Surface soil salt deposition leads to a physiological water shortage of H. ammodendron seedlings, and affected regeneration of seedlings. The coverage and decline rates of H. ammodendron have a quadratic function relation with groundwater respectively and in a linear correlation with the soil surface conductivity. The results concluded decline of groundwater level. Its degree of mineralization and soil surface salinization are three dominant factors in this region of H. ammodendron degradation