Wind tunnel simulation and evaluation of soil conservation function of alpine grassland in Qinghai-Tibet Plateau

Aiming at studying soil conservation function of alpine grassland in the Qinghai-Tibet Plateau, this paper simulated soil erosion changes under different degrees of human disturbance in a wind tunnel laboratory. Three types of grasslands were selected, which include alpine meadow (QH-1), alpine steppe meadow (QH-2) and alpine steppe (QH-3), and the soil erosion rate was taken as the index to measure soil conservation function. The experimental results show that the soil erosion rates of three grassland samples increase with wind velocity under different treatments but the increment of erosion rate varied greatly. Under original status, soil erosion rates are in turn QH-1 < QH-2 < QH-3, which indicates that the soil conservation services are QH-1 > QH-2 > QH-3. When the aboveground vegetation was cut, the soil erosion rate change of QH-1 is the same as that of QH-3 and compared with the original status both of them changed a little. And when the root system was destroyed the erosion rates range in turn as QH-1 < QH-2 < QH-3. So the data suggest that soil conservation service for the three types of grasslands should be QH-1 > QH-2 > QH-3. The economic values of soil conservation were estimated, which include the values of organic carbon fixation, nutrient retention and reducing soil disuse.