摘要
黄土高原的退耕还林是一项史无前例的宏伟工程,成功实施该项工程对恢复该区严重恶化了的生态环境和减少黄河下游水患具重大现实意义。当前植树造林面临的需要解决的重要问题是土壤干化。土壤干化导致人工林生长不良,甚至干枯死亡,查明土壤干化原因对在植树造林工作中采取合理对策有重要作用。野外调查和资料分析显示,陕北黄土高原土壤干化原因有两个方面:一是自然原因;二是人为原因。自然原因包括该区本来降水量较少,近50a来降水减少和气温升高3个方面。人为原因包括植被破坏,人工林密度过大,在不适于森林发育的地带进行了造林和没有遵循植被演替规律进行了造林4个方面。根据黄土高原已经发生了变化的自然条件,本文建议在陕西延安以南至关中盆地南缘的落叶阔叶林带应采取植被的自然恢复或人工草灌和稀疏的植树相结合的措施恢复森林植被,在延安至长城之间的森林草原带应以人工发展优良草灌为主,配合大间距的植树恢复森林草原植被,在长城以北以种草为主。为提高乔木成活率和确保人工林正常生长,继续采取建造鱼鳞坑等集雨工程措施是很必要的。
Returning cultivated land back to forest in the Loess Plateau is a great unprecedented engineering, and its successfully implementation has very important actual significance to the restoration of ecological environment deteriorated seriously and can decrease flood in the lower reaches of the Huanghe River. At present, soil drying is the sever problem in afforestation, which results in artificial forest not growing well and even withering. The field survey and the data analysis show that the cause of soil drying in the Loess Plateau of northern Shannxi has two aspects: natural causes and anthropogenic causes. Natural causes include the less normal rainfall, the further decreasing rainfall and the increasing temperature in recent 50 years. Anthropogenic causes include destroying vegetation, the great density of artificial forest, the afforestation in unsuitable areas, and not obeying the regularity of vegetation succession. Based on the present situation in the Loess Plateau, the paper suggests that measures that combine the natural vegetation restoring with sparsely re\|afforestating should be taken to restore the forest vegetation in the broadleaf forest zone southward from Yanan to the southern rim of the Guanzhong basin; measures that combine planting grass and bush predominantly and planting tree in large interval should be taken to restore the forest vegetation in the forest\|steppe zone between Yanan and the Great Wall; measures of mainly planting grass should be taken in the zone northward from the Great Wall. In afforestation it is necessary to take water\|harvesting engineering measures such as building pits arranged like fish scales for raising the survival rate of arbor and ensuring normal growing of artificial forest.
出处
《中国沙漠》
CSCD
北大核心
2003年第6期612-615,共4页
Journal of Desert Research
基金
教育部重大项目(01JAZJD770014
2000ZDXM770013)
陕西自然科学基金项目(2002D02)
国家自然科学基金项目(40071006)
关键词
黄土高原
人工林
土壤干化
植树造林
the Loess Plateau
soil drying
afforestating
measures
