Abstract:
Based on GIS technique, vegetation coverage change was described in recent years by using SPOT VEGETATION, land use and vegetation coverage ratio were interpreted by using TM , furthermore, slope farmland and soil erosion intensity were analyzed by overlay method for understanding the effect of the project of returning farmland to forest or grassland(grain for green). The territory profile of Wuqi County in northern Shaanxi Province was gradually clear-cut on SPOT VEGETATION images from 1999 to 2007. It is the green mark that the project makes. Vegetation was not only getting better and better in Wuqi county, but also getting better than the surroundings. Comparing with the status in 1997, 75.15% of farmland was no longer cultivated, which was mainly returned to pasture, woodland or garden in 2007. The coverage ratio of woods and grass was greatly increased from 37.06% in 1997 to 80.60% in 2007. 80%-90% of slope farmland with the gradient more than 25° was not cultivated. Soil erosion intensity was decreased as a whole, the areas of high and violent intensity soil erosion decreased from 42.52% in 1997 to 17.35% in 2007. However, its situation is still severe and it needs to be improved.further.