关键词: 陕西黄土高原, 土壤干层, 植树种草, 应对措施

Abstract: According to the investigation and the determination of soil moisture content in Guanzhong area and the North of Shaanxi, the scope of soil-drying layer and effects on afforestation are discussed. The results indicate that the soil-drying layer is widely distributed and has extended to the Guanzhong Plain. There are different origins and levels of soil-drying layer development in different vegetation zones. In ecological and environmental construction, the recovery of different kinds of vegetation should accord to the different levels of drying layer's development. In the deciduous broad leaf forest areas of less drying layer in south beyond Yan an, measures of combining grasses, shrubbery with trees should be taken to recover forest vegetation. In the forest-steppe areas of serious drying layer between Yan an and the Great Wall, grasses and shrubbery vegetation should be developed first and then forest-steppe vegetation should be developed. In the steppe areas of serious drying layer in the north beyond Yan an, steppe should be restored naturally. Tree planting is unsuitable in the areas of serious drying layer because it cannot improve the ecological environment and will lead to bad results to soil moisture. In ecological and environmental construction of tree planting and grass planting, we should choose growing slowly or moderately grass and shrubbery instead of plants which grow fast and consume a lot of water.

Key words: the Loess Plateau of Shaanxi, soil-drying layer, afforestation, relevant measures