基于地貌和空间分异特征的中国近期耕地变化分析

ON CURRENT CULTIVATED LAND CHANGE BASED ON GEOMORPHOLOGY AND SPATIAL DIFFERENTIATION CHARACTERISTICS

利用我国“八五”资源环境遥感数据库与“九五”县级土地资源遥感调查数据库分析了 90年代初期到中期我国耕地的变化情况 ,结果显示我国耕地变化存在区域差异 ,其中黄淮海平原及山东丘陵区减少最为显著 ,东南丘陵区耕地为显著增加 ;通过分析各土地利用区划一级单元内不同变化度基本研究单元所占总体耕地面积比例情况 ,说明各区域内耕地动态差异也比较大 ;为了定性反映不同区域内由于耕地面积的变化所引起的整体耕地质量的相对变化 ,运用全国 1 :1 0 0× 1 0 4地貌图与基本研究单元图的叠加 ,统计分析了不同地貌类型上的耕地面积变化量。总体上 ,我国平原地区的耕地减少绝对量与相对量均最大 ,而高原地区耕地面积是增加的 ,表明我国耕地总体质量有所下降。为了切实保护耕地和生态环境 ,必须严格控制平原地区耕地的非农业利用 ,减少山区的自然灾害毁地 。

Using both land resources database accomplished during the 8th Five Year Plan period and that accomplished during the latest 10th Five Year Plan period, this paper analyzes the changes on cultivated land during the early 1990s to the mid 1990s in China. The result indicates the existence of apparent regional differences in change. Of which the division of Huang Huai Hai Plain witnessed the largest scale decrease of cultivated area whereas the division of hilly area in Southeast China experienced the substantial expansion of cultivated land area. It points out that dynamic differences of cultivated land in each division are also obvious according to the analyses of proportional changes of cultivated land area of various basic research units at first level division to the total cultivated land area. In order to compare quality changes of the cultivated land on the whole, the overlaying of 1:1,000,000 national geomorphologic map with basic research unit map was done and geomorphologic type of each unit as well as cultivated land change of each geomorphologic type in each land use division was obtained. Generally speaking, both the absolute decrement and the relative decrement of cultivated land in plain area are the highest among the five geomorphologic types whereas on the highland, decrease of cultivated land was the most.