Abstract:In order to investigate the spatio-temporal dynamic characteristics and the main controlling factors of soil CO2 flux during the process of vegetation restoration in Hobq desert, and clarify the variation trend of soil organic carbon content and density, the mobile dune, semi-fixed sand, algal crust fixed sand and mixed crust fixed sand were taken as the object, and soil CO2 flux, temperature and moisture were continuously measured using the static closed chamber-gas chromatography technique, and the content and density of soil organic carbon were measured and calculated. The results showed that in the growing season, the spatial and temporal variation of soil CO2 flux was obvious and increased with vegetation restoration, CO2 flux was in an order of mixed crust fixed sand (210.28 mg/(m2·h)) > algal crust fixed sand (177.45 mg/(m2·h)) > semi-fixed sand (117.34 mg/(m2·h)) mobile dune (65.61 mg/(m2·h)). Soil CO2 flux of the four sites were significantly positively correlated with soil temperature. CO2 flux of mobile dune was significantly negatively correlated with deep soil moisture, and were significantly negatively correlated with surface soil moisture in other sites. Soil organic carbon content density also increased with vegetation restoration:mixed crust fixed sand (1.32 g/kg, 0.94 kg/m2) algal crust fixed sand (1.03 g/kg, 0.74 kg/m2) > semi-fixed sand (0.45 g/kg, 0.36 kg/m2) > mobile dune (0.27 g/kg, 0.24 kg/m2). Both the content and density of organic carbon decreased with soil depth. Soil surface carbon flux was significantly positively correlated with organic carbon density at the depths of 0-10 cm and 10-20 cm. The above results demonstrated that artificial planting could promote vegetation restoration and sand fixation, which effectively improved carbon emission flux of sandy soil, moreover, significantly increased carbon storage capacity and potential, thus could alter carbon cycle pattern of desert ecosystems.