Abstract: The wind prevention and sand fixation function are the main ecological service function of sand-prevention belt in northern China, which is important for the construction of ecological safety barrier in northern China. In this study, the sand-prevention belt in Inner Mongolia was selected as the study region, the revised wind erosion equation (RWEQ) was applied to quantify soil wind erosion mass and wind prevention and sand fixation mass in 2000 and 2015. We analyzed the spatial and temporal variations of wind prevention and sand fixation function, and the effects of land-use change on wind prevention and sand fixation function, aiming to provide reference for improving ecological service function of sand-prevention belt in northern China. The results showed that: (1) soil wind erosion mass ranged from 0.007 to 48.9 kg·m^-2 in 2000, with a total soil wind erosion mass of 29418.3×10⁸ kg, while it ranged from 0.002 to 48.2 kg·m^-2 in 2015, with a total soil wind erosion mass of 28727.3×10⁸ kg. From 2000 to 2015, the total amount of wind erosion in the whole region reduced by 691.1×10⁸ kg. The intensity of soil wind erosion was mainly moderate, intensive, and severe, which together accounted for 71.6% of the total area in 2000, while it was mainly slight, moderate, and severe, accounting for 78.7% of the total area in 2015. The area of the regions with soil wind erosion of intensive, extreme, and severe intensity decreased by 101079 km², while the area with soil wind erosion of mild and moderate intensity increased by 100572 km². (2) The average amount of wind prevention and sand fixation per unit area ranged from 0 to 42.4 kg·m^-2 in 2000, while it ranged between 0 and 45.4 kg·m^-2 in 2015. The average amount of wind prevention and sand fixation per unit area was the highest in Chifeng City, followed by Tongliao and Ordos cities, while Wuhai and Shizuishan cities had the lowest values. The total amount of wind prevention and sand fixation in the study region was increased by 646.0×10⁸ kg from 2000 to 2015. The level of wind prevention and sand fixation functions was mainly low, relatively low, and medium, together accounting for more than 75% of the total area. The area with wind prevention and sand fixation functions of relatively high and high levels increased by 1979 km². (3) From 2000 to 2015, the total area of desertdecreased and was mainly converted into grassland and cultivated land. The converted grassland area was 6460.7 km², while the converted cultivated land area was 439.2 km². Our results indicated that the capability of wind prevention and sand fixation function in the sandprevention belt in Inner Mongolia significantly was improved over the past 15 years due to revegetation, but varied greatly among different parts of the study region. Therefore, we should take different strategies in different sand-fixing function zones, and pay more attention to the improvement of sand-fixing function in the western part.

Key words: revised wind erosion equation, soil wind erosion, land use/cover type, forestry ecological engineering.