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土地是人类赖以生存的最重要的资源。当今,水土流失对土地资源的破坏已成为人类面临的一个十分严峻的问题。据联合国环境规划署估算,全世界每年土壤流失量达240亿吨,受沙漠化影响的面积达3800万km~2,并正以每分钟44公顷、每年23万km~2的速度不断扩大。我国的流失面积达150多万km~2,占国土面积的16％,每年的土壤流失量在50亿吨以上,相当于全国耕地表土平均每年减少1cm厚。江西省的水土流失情况也是相当惊人的。据1984年规划资料,全省水土流失面积达3.4万km~2,占总土地面积的20.5％(见表1)。水土流失现已成为制约我省经济发展的重要因素之一。
Land is the most important resource upon which mankind depends. Nowadays, the destruction of land resources by soil and water loss has become a very serious problem facing mankind. According to estimates by the United Nations Environment Program, soil erosion amounts to 24 billion tons annually in the world and the area affected by desertification reaches 38 million km2 and is expanding at a rate of 44 hectares per minute and 230,000 km2 per year. China’s drainage area amounts to more than 1.5 million km 2, accounting for 16% of the total land area. The annual amount of soil loss is more than 5 billion tons, which is equivalent to a 1cm-thick reduction in the topsoil of the entire country. Soil and water loss in Jiangxi Province is also quite alarming. According to the 1984 planning data, the province’s soil erosion area reached 34,000 km 2, accounting for 20.5% of the total land area (Table 1). Soil and water loss has now become one of the important factors restricting the economic development of our province.