近10年来中国耕地资源的时空变化分析

Spatial-temporal Changes of Cropland in China for the Past10Years Based on Remote Sensing

根据中国资源环境数据库中的耕地数据以及20世纪80年代末期、1995年和2000年3期覆盖全国时间跨度约为10年的遥感数据,对中国耕地时空变化进行分析。总趋势表明,近10年来我国耕地资源总量有所增加;东部及沿海地区优质耕地迅速减少;东北地区和内蒙古自治区耕地大量开垦;水田旱地转换明显。利用GIS方法将耕地变化数据与中国生态环境质量数据进行叠加,表明近10年来耕地的生态环境质量下降了。近10年耕地动态变化的空间分布表现出13种动态格局。对80年代末至1995年(前5年) 和1995年至2000年(后5年) 这2个时间段内的耕地变化进行对比分析,表明了前5年与后5年耕地变化的动态格局有空间上的相似性,但前后变化幅度相差较明显。近10年来气温的升高与中国水田北移有较好的一致性,而降水的减少对西北地区耕地的撂荒和开垦有明显作用。中国经济的发展所导致的城市化过程使得大量耕地被占用。近10年来相关的耕地政策对控制耕地面积的减少有作用,但耕地的总体质量却下降了,这直接影响了粮食产量。

Based on remote sensing and geographic information system, the changes of spatial distribution of cropland for the past 10 years in China are studied. The results show that the total area of cropland is increasing while the cropland in the southeastern part of China is decreasing, whereas the cropland in Northeast China and the arid and semiarid areas of China is expanding. The ecological and environmental quality of reclaimed and lost cropland is evaluated. Thirteen patterns of the spatial changes of cropland in China can be classified into 13 areas correspondingly. Each area has its cropland transformation characteristics. In each area, the patterns of the former five years and the latter five years are similar on the whole. But the quantity of changed cropland is different. In some areas, the croplands increase or remain unchanged in the former five years but decrease in the latter five years, and vice versa. The nationwide warming is in better coincidence with the northward shifting of the paddy fields in China; at the same time, the drought in Northwest China causes the coexistence of considerable scale of reclamation and loss of cropland. The economic development induced rapid urbanization process is closely related with the occupancy of vast area of cropland for construction. Although the total food production is stable, the more area of cropland in a province is lost, the more production drop occurs.