以土壤水分条件及地形等因素为依据 ,进行了立地条件类型的划分 ,共划分了 3个类型组和 9个类型 ,并提出了小流域林草布局的典型模式。根据立地条件类型划分和小流域布局模式可以看出 ,延安研究区有条件发展乔木林 ,但并不是到处都可发展乔木林 ,因此 ,依据立地条件类型进行造林种草的合理布局进行植被建设是取得成功的必要措施。 Based on the factors of soil moisture and topography, the classification of site conditions was divided into three types and nine types, and a typical pattern of forest and grass layout in small watershed was proposed. According to the classification of site conditions and the pattern of small watershed layout, it can be seen that the development of arbor forest is conditional in Yan’an study area, but the arbor forest can not be developed everywhere. Therefore, the rational layout of afforestation and grass planting according to site conditions The necessary measures for success.