MATERIALS AND METHODS
Experimental sites
The study area is located in the lower reaches of the Heihe River, extending between latitudes 4020′ –4230′ N and
longitudes 9930′ –10200′ E, in the county of Ejina, Inner Mongolia, Northwest China, with an area of 3 104 km2
This region has a continental climate with a mean annual temperature of approximately 8 C, a maximum daily temperature of 41 C (July) and a minimum of 36 C