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土地沙质荒漠化是中国北方最为严重的环境和社会经济问题之一。荒漠化过程主要受人类活动与脆弱生态环境相互作用的制约 ,也就是说土地利用方式与强度是影响荒漠化发展或逆转的主要因素。由于日益增大的人口压力所导致的人类影响的强化 ,中国北方的农牧业交错地带一直向北延伸 ,使得大面积牧场转变为农田并破坏了天然植被。其结果是土地变为易风蚀土地 ,荒漠化发展异常迅速。据统计 ,因人类活动影响所造成的荒漠化土地面积中 ,2 5 %起源于过度耕种 ,2 8%起源于过度放牧 ,32 %起源于过度樵采燃料 ,8%起源于滥用水资源。在过去 5 0年中 ,沙质荒漠化面积不断扩大 ,至 90年代中期其总面积已达到 35 0 0 0 0 km2 。遥感监测表明 ,从 5 0年代到 70年代中期 ,荒漠化土地的年平均增长率为 15 6 0 km2 ;70年代中期到 80年代末为 2 10 0 km2 ;过去 10年中为 2 46 0 km2 。但也有一些防治沙漠化的成功典型事例 ,在这样的地区 ,土地利用较为合理 ,沙质荒漠化土地已经逆转 ,而且可以更加有效地用于农牧业生产。
Sandy desertification of land is one of the most serious environmental and socio-economic problems in northern China. The process of desertification is mainly constrained by the interaction between human activities and the fragile ecological environment. That is to say, land use patterns and intensities are the main factors that affect the development or reversal of desertification. Due to the intensification of human influence caused by the increasing population pressure, the farming and animal husbandry interlaced areas in northern China have been extending northward, transforming large-scale pastures into farmland and destroying natural vegetation. As a result, the land becomes easily eroded and the desertification develops exceptionally rapidly. According to statistics, 25% of the desertified land area caused by human activities originated from over-cultivation, 28% originated from overgrazing, 32% originated from over-firewood fuel and 8% from the abuse of water resources. Over the past 50 years, the desertification area has been expanding steadily, reaching a total area of 35,000 km2 by the mid-1990s. Remote sensing monitoring shows that the average annual growth rate of desertified land from the 1950s to the mid-1970s was 1560 km2; from the mid-1970s to the late 1980s, it was 2 10 km2; and in the past 10 years it was 2 46 km2. However, there are also some typical success stories of combating desertification. In such areas, land use is more reasonable and desertified desertified land has been reversed and can be used more effectively in agriculture and animal husbandry.