LAND USE AND ENVIRONMENTAL PROBLEMS OF WATERLOGGED AREAS -A CASE STUDY IN AFRICA-

丹博、法达玛和姆布加等季节性涝地对非洲的农业生产和畜牧业起着重要作用。据说这些湿地覆盖了非洲总面积的3%以上。例如，赞比亚的丹博的面积约占总面积的4.6%。随着农业生产成为撒哈拉以南非洲地区的一项重要任务，这些湿地地区因其潮湿的条件而开始受到人们的关注。自20世纪80年代以来，许多非洲国家实施了结构调整计划（SAP），湿地的价值开始得到广泛认识。SAP造成的许多剧烈变化，如农业市场的自由化、农业投入补贴的削减、公共服务的缩减、当地货币的贬值以及政治的民主化，都对加强湿地的种植产生了影响。人们已经开始利用土地一年四季不仅生产蔬菜，而且生产食品。由于这些湿地的环境在自然界中是非常脆弱和混杂的，开垦的湿地面积越多，出现的环境问题就越多。在赞比亚、坦桑尼亚和尼日利亚进行的实地研究清楚地表明，今天非洲迅速的社会经济变化对湿地的利用产生了强烈的影响。这些湿地的集约利用在促进农业生产的同时，也加剧了土地退化、干旱化和水土流失。这表明，今天非洲迅速的社会经济变化可能对未来的环境退化产生强烈影响。

The wetlands like dambo, fadama and mbuga which are seasonally waterlogged have playd an important role for agricultural production and pasturing in Africa. These wetland is said to cover more than 3 per cent of total area in Africa. Dambo in Zambia, for example covers an area of about 4.6 per cent of the total.As agricultural production had become an important quest in Sub-Saharan Africa, these wetland areas have begun to get much attention because of its moist conditions. Since 1980s when many of African countries adopted Structural Adjustment Program (SAP), the value of wetland has begun widely acknowledged. Many of drastic changes caused by SAP,such as liberalization of agricultural market, cutback subsidy for farm inputs, retrenchment of public services, devaluation of local currencies, and plus the democratizasion in politics, has an effect to intensify the cultivation of the wetland. People has begun to use the land to produce not only vegetables but also foodstuffs all through a year.As the environment of these wetland is very vulnerable and intermingled in nature, more wetland area is brought under cultivation, the more environmental problems occur. The field studies which have carried out in Zambia, Tanzania and Nigeria, have made clear that the rapid socio-economic change in Africa today had strong influence on the use of the wetland. Intensive use of these wetland has contributed to the increase in agricultural production, however, it also contributed to the promotion of the land degradation, desiccation and soil erosion.This shows that the rapid socio-economic changes in Africa today may have strong impacts on the environmental degradation in the future.