This experiment was conducted at an alpine meadow in the Haibei
Alpine Meadow Ecosystem Research Station of Chinese Academy of
Science, which is located in a large valley surrounded by the Qilian
Mountain of the northeast of Qinghai-Tibet Plateau (37°
37′N, 101°
12E′)
in Qinghai province. It has a typical highland continental climate with
cold and long winter but cool and short summer. The annual mean air
temperature recorded at the station is −1.7 °C [2]. The day/night temperature
variation is substantial due to strong sun radiation. The annual
mean precipitation is 560 mm and 85% of rainfall is within the growing
season from May to September