三峡库区生态环境与农业持续发展

ECO ENVIRONMENT AND AGRICULTURAL SUSTAINABLE DEVELOPMENT IN THREE GORGE RESERVOIR AREA

三峡库区系指从重庆到宜昌段为水库波及的２０个县市。该区属川东陵谷区，以山地丘陵为主，河谷平坝比重小，种植业垂直分异明显，海拔５００ｍ以下为三熟制区，８００～１４００ｍ为一熟制区，两区间系两熟制区。由于人口压力，毁林开荒普遍，结果森林复盖率锐减，坡耕地增多，水土流失严重，粮食产量低而不稳，生态环境处于退化状态。因修建水库海拔２００ｍ以下良田被淹，加之移民与城镇迁建占用土地，人地人粮关系更趋紧张，在后备宜农土地资源短缺条件下，为把该区建设成经济发达环境优美的经济区，在经济发展的同时，应寻求对策，把握生态环境建设与农业持续发展。

Three gorge reservoir area generally includes 20 counties or cities which are involved in the reservoir from Chongqing city to Yichang city. This region belongs to hilly area of east Sichuan province where mountains and hills are dominant, and valleys and flatlands take a low proportion, plantation appears obvious vertical differentiation, i.e. tripple cropping areas are below 500 m a.s.l., single cropping areas are distributed from 800 m to 1 400 m a.s.l., and between the two areas are double cropping areas. Because of the widespread population pressure, deforestation and reclamation, vegetation cover degree decreases markedly, slope cultivated lands increase, water and soil loss are very serious, crop yields are low and unstable, eco environment is in a state of degradation. Well cultivated lands below 200 m a.s.l. will be submerged by building the reservoir, while migration of settlers. and city or town moving and construction need large land area, so human land and human grain relationships will become more and more tense. Under the condition of shortage of reserve agricultural land resources, in order to build an economic region with developed economy and fine environment, we should grasp eco environment construction and agricultural sustainable development, and take appropriate measures.