提出了土地利用转移流和土地利用活跃度的概念,基于Landsat遥感影像数据,采用土地利用变化测度模型,以5年和25年两种时间尺度对黄土台塬区土地利用时空动态特征进行分析,并将密度制图法应用到土地利用变化的空间集聚特征识别中。研究表明:①黄土台塬区耕地占绝对优势,后备耕地资源严重不足,林地、草地、水域比例较低,存在较大生态风险;②耕地与建设用地、草地、林地之间的转移关系是黄土台塬区土地利用转移的关键关系,决定着台塬区土地利用变化特征;③1985-2010年耕地转建设用地流高达26668.80hm2,占土地转移流40.75%,草地转耕地流18923.90hm2,占28.91%,建设占用耕地情况严重,耕地占补平衡主要通过挤占草地实现;④25年以来,土地利用变化对水域扰动最大,其次为森林,草地第三;⑤土地利用变化存在阶段性,1990-2000年土地利用变化速率高于其他时段;⑥不同时间尺度下土地利用变化的空间集聚特征不同,25年尺度下城镇附近土地变化幅度较高,5年尺度下土地利用变化热点区由台塬中部向东西边缘区推移。
The conception of land use change flow was put forward in this paper, and the dynamics of land use change in the loess platform region was analyzed with the models of land use change. In addition, the spatial agglomeration of land change flow was studied. The results are obtained as follows. The proportion of cultivated land is predominant in the study area, however, that of unused land is very low, which means that reserved cultivated land resource is scarce. The proportions of forest land, grassland and waters are low, indicating that the ecosystem is at risk. The land use change flows relationships of cultivated land and built-up land, cultivated land and grassland, cultivated land and forest land played key roles in the land use change of the loess platform region. The flow of cultivated land to built-up land was the main reason for the loss of cultivated land resources, and the flow of grassland to cultivated land was the main complement source of cultivated land. The land use change flow of cultivated land to built-up land was 26668.80 ha from 1985 to 2010, accounting for 40.75% of the total. The flow of grassland to cultivated land was 18923.90 ha, accounting for 28.91% of the total. The disturbed degree from high to low is water ecosystem, forest ecosystem, and grass ecosystem. Land system was relatively stable from 1985 to 1990, yet it changed significantly from 1990 to 2000. The spatial features of land use were different at different scales. The land use change rate around cities was higher than that of other regions at a 25-year scale, however, the region with a high land change rate changed from the central part of loess platform region to the marginal zone at a 5-year scale.