Ecological Risk of Yulin Area in Northern Shaanxi Under the Condition of Vegetation Coverage Improving

In recent decades, with the mega-eco-environmental projects, such as “Grain for Green Project” performed, the vegetation coverage in Yulin area has increased notably and the ecological environment has improved significantly. At the same time, the river discharge decreased, the groundwater level dropped, has become more prominent. Summarize these possible risks and put forward some pertinence countermeasures are of great significance for the sustainable development of Yulin area. Based on existing data, the article sort out various problems that occurred in recent years in Yulin area. And then analyzed the possible reasons, and finally put forward some suggestions. The results show that the average annual NDVI of Yulin City increased obviously, grassland and forest increased rapidly, and the desertification land reduced clearly in last 20 years. But in the mean time, the discharge of larger rivers in Yulin area has decreased obviously in the past 50 years, especially the Wuding River, Tuwei River, and Kuye River. The groundwater level in the whole area of Yulin dropped about 2-10 m. In recent years, Yulin City began to reclaim cultivated land in the sandy land on a large scale by using the cropland balance policy. In view of the problems occurred in resent years are mostly related to water, so the Yulin area should resolutely implement the policy of water-based production, strengthen the optimal allocation of water resources, increase the utilization of mine water and the water of Yellow River. Vegetation restoration should mainly dominated by shrubs and herbs. The ecological environment problems occurred in resents years, and countermeasures and suggestions of the Yulin can provide reference materials for the sustainable development of resource-based cities in the ecologically fragile area of the middle reaches of the Yellow River.