2.1 Site Description
The study was conducted in Alxa League, the westernmost part of the
Inner Mongolia Autonomous Region. It is located at 37°24′
~ 42°47′N, 97°10′ ~ 106°53′E. The area
is dominated by high plains, with large desert and Gobi areas, followed
by grassland areas, and smaller mountain, forest, and arable areas. It
has an altitude range of 820 ~ 1 400 m. The region has
an arid climate and strong winds, and is a typical arid desert area. The
average annual temperature is about 8.3 ℃, the average annual
precipitation is 40-180 mm, mainly in July and August, and the average
annual evaporation is 2,400-4,200 mm. Soil types have obvious zonal
characteristics, from northwest to southeast, gray-brown desert soil,
gray-desert soil and gray-calcium soil are distributed in order, and in
the lake basin area there are saline soils. The vegetation types are
mainly desert vegetation, oasis vegetation and mountain vegetation.
Natural poplar forests grow in the Ejin Oasis area, while the presence
of the Helan Mountains enriches the biodiversity and complexity of the
Alxa Plateau system. Alxa region is an ecologically fragile area, which
is one of the birthplaces of sandstorms in China. In recent years,
around the three major deserts, a large area of artificial afforestation
has been carried out, and artificial H. ammodendron plantations have
become an important artificial barrier to curb land desertification and
promote ecological restoration in the region. Fig. 1 shows the
geographical location and experimental survey area of Alxa.