黄河、长江流域水土流失现状及森林植被保护对策

Forest Protecting from a Viewpoint of Soil and Water Loss Actuality of Huanghe River and Changjiang River Valley

我国是世界上土壤侵蚀最严重的国家之一,每年流失土壤60亿t,占世界总侵蚀量(600亿t)的1/10,每年的入海泥沙量约20亿t,占世界入海泥沙量(240亿t)的1/12。由于严重的水土流失,不但造成土壤中养分流失,化肥、农药等污染物对水质的污染,导致水体富营养化;而且大量的侵蚀泥沙淤积湖泊、抬高河床,降低了其调泄洪水的能力,洪涝灾害频繁发生;此外,表土的大量流失,土层变薄,土壤性状恶化,导致土壤生态系统的抗灾功能减低。为此,在分析我国主要水土流失类型区黄河、长江流域土壤侵蚀的成因、特点、危害及其与植被恢复关系的基础上,提出了切实可行的森林植被恢复技术。

China is one of the most serious soil erosion countries in the world.The total soil erosion quantity is about 6 000 million ton each year and it takes about 1/10 of the total erosion amount of the whole world.Almost 2 000 million ton of the eroded soil is transported into the sea every year.On the one hand,the serious soil erosion will cause both the nutrient loss of soil and water quality pollution because of the chemical fertilizer and pesticide from soil.On the other hand,the accommodation and discharge capability of rivers and lakes are decreased greatly for the season of soil accumulation on the bottom of rivers and lakes.Furthermore,The contradiction function of soil system on calamity is reduced largely with the decreasing of soil depth and deteriorating of soil characteristics.Based on the analysis,the relation of soil erosion formation cause and characteristics as well as harmfulness with vegetation restoration,some of the important and suitable measures on forest vegetation restoration are brought forward in the paper in order to control the serious soil erosion.There is a great guidance action on the ecological environment construction in the western part of China.