保护性耕作是防止沙尘暴发生的有效途径

由于黄土高原退耕还林工程涉及区域广阔，推进迅速，实施经验欠缺，因此目前存在科学规划、充分论证、有序推进不力，造林成活率低．科技支撑不足等不容忽视的问题。根据黄土高原退耕还林工程的现状及相关调查研究结果，谨提出建议如下：(1)明确退耕还林工程在生态建设中的正确定位；(2)增强退耕区生态环境建设与实施综合治理的政策可操作性；(3)加大配套措施实施力度，确保退耕成果不反弹；(4)国家应明确政策，支持封禁，促进植被自然恢复；(5)重视粮食的风险问题与对策。

Conservaion Tillage Being an Effective Measures of Prevent Standstorm

The conversion of farmland to forestland or grassland on the Loess Plateau is a challenging ecological project. Much attention should be intensively focused on rational plan and extensive argumentation on the program and the problems on slow orderly progresses, low survival rate of tree seedlings in the afforestation and less scientific and technological support in the program because the program of conversion of farmland to forestland or grassland was launched on large scale and carried out quickly on the Loess Plateau, and there were few experiences on fulfilling this program. Based on the current situation and investigation results on the processes of this program, the presented suggestions on this program are as follows: manifesting the significant roles of conversion of farmland to forestland or grassland in ecological improvement, intensifying the practicality of the policy on carrying out eco-environment improvement and comprehensive harnessing in the farmland-converted area, strengthening the integrated measure execution in terms of preventing the recession of farmland conversion, supporting to confine grazing in order to promote restoration of natural vegetation according to specific policy issued by government, and paying attention to the food supply risk and the corresponding countermeasures.