Abstract: Qidukou is located in the confluence reaches of Chumaer River and Tongtianhe River and belongs to the headwaters of Yangtze River. In recent years, the temperature increased in Qinghai-Tibet Plateau, and the climate changed to aridity in the source region of Yangtze River. In addition, high and over grazing made the problem of grassland desertification presented in Qidukou, Tongtian River. To control the further spread of the desertification grassland, we have observed characteristics of the wind-blown sand environment, and have made a mechanical and plant sand-fixation experiment in this region. The observation results showed that the annual-average wind speed was 1.95 m·s^-1, the maximum instantaneous wind speed was 20.63 m·s^-1, the direction of prevailing sand-moving wind was westerly wind (include W, WSW and WNW), the annual sand drift potential was 93.06 VU, the sand transport direction was 107.54°, and the annual sand transport amount was 3 007.30 g·cm^-1 in Qidukou, Tongtian River. After two years of mechanical and plant sand-fixation experiment, concave curved surfaces formed in the HDPE sand barriers, which made the sand bed fixed, and controlled the dune movement effectively. As the growing of artificial vegetation in the sand barriers, the soil microenvironment in the experimental zone improved gradually:(1) Silt and clay content increased in HDPE sand barriers without/with artificial vegetation, it was 6.4 and 9.1 times more than that in drift sand. (2) Organic content increased, which was 0.91, 1.48, 2.02 g·kg^-1 in drift sand, sand barriers without artificial vegetation, and sand barriers with artificial vegetation respectively. (3) Soil hardness increased, which was 0.52, 1.25, and 2.12 kPa in drift sand, sand barriers without artificial vegetation, and sand barriers with artificial vegetation respectively.

Key words: Tongtianhe River, desertification, HDPE sand barriers