关键词: 土地沙漠化, 防治区划, 沙漠化面积, 沙漠化防治, 陕北地区, 滥用土地, 综合农业区划, 陕北榆林, 黄土丘陵, 生态环境因子

Abstract: The north Part of Shaanxi Province is situated in the Southeastern Mu Us Sandy Land, it is one of the severe desertification areas in China. The desertified land areas cover about 21,713 sq.kilometers, occupying 49.8% of the total area in Yulin Prefecture. The desertified lands can te divided into the following four types (see "the MaP of Inventorying of the Types of Desertification and Its Prevention in the North of Shaanxi Province" 1: 400000): 1. Latent desertified land; 2. On-going desertified land; 3.Severe desertified land; and 4.Most severe desertified land. The development of desertification in the area is gradually changing from bad to worse from southeast to northwest. The main factors causing desertif ication are the dry and windy climate, sufficient sand sources, severe erosions, blind growth of population, mis-management of agriculture and animal husbandry, destruction of vegetation arid irrational utilization of land resource. The desertification processes can be divided into two types in its landscape loess area and Ordos Plateau area. Since the founding of the People's Republic of China, botter results have been obtained in the case study area on combating desertification, but it is still going to develop. The authors have divided Yulin Prefecture into 2 zones and 12 sub-zones for combating the world- wide problem, The physical characteristics, approaches and measures for the issue in each zone and sub-zone respectively presented in the study.