LAND DEGRADATION AND ITS CONTROL STRATEGIES IN CHINA

摘要

Human induced land degradation refers to decline or loss of biological or economic productivity resulting from a process or combination of processes, including displacement of soil matreial, terrain deformation and loss of nutrients and/or orgnic matter through wind erosion, water erosion, secondary salinization and pollution. Wind erosion is a major problem in the dry land of China and the area of sandy desertified land caused by wind erosion has reached 371,000 km 2. Water erosion frequently occurs in hilly and mountainous areas where 1.79 million km 2 of land have been observed and degraded land area affected by secondary salinization now covers 63,000 km 2 in China. Statistical data indicated that depletion of soil nutriution is a serious problem in China. Some 460,000 km 2 of cultivated or 46 percent of the total cultivated land area is deficient in P, and 330,000 km 2 of cultivated land or one-third of nation′s total is deficient in K. Adverse human activities are recognized as a principal reason of land degradation. In northern China, 30.1 percent of land degradation caused by over grazing, 26.9 percent by over reclamation, 33.7 percent by excessive fuel collection, 9.6 percent by mis-use of water resources, as well as 0.7 percent by industrial, mining and transportation construction. In southern China, 37 percent of degraded land caused by deforestation, 35 percent by slopeland reclamation, 18 percent by improper afforestation, and 10 percent by industrial, mining and transportation construction. Following the discussion of the causes and disasters of land degradation, this paper presents the achievements gained in prevention and control of land degradation since 1949. The several control strategic measures in combating land degradation such as prompting public awareness and people’s participation, strengthening national laws and policies formulation, carrying out projects on rehabilization and monitoring, are proposed by the end of this paper.