近20年中国北方13省的耕地变化与驱动力

Change Process of Cultivated Land and Its Driving Forces in Northern China during 1983-2001

利用1983年1月至1999年12月长时间序列NOAA/AVHRR NDVI数据和2001年逐旬SPOT/VGT数据,获取了中国北方13省1980s初期、1990s初期、1990s末期和2000s初期地表土地覆盖特征,阐述了中国北方13省的耕地变化过程,并重点讨论了人类活动对耕地变化特征的影响和耕地变化的驱动力.发现:(1)裸地、耕地等弱生态用地面积持续增加,而林地和草地等生态功能用地和混合功能用地持续减少是我国北方1983～1999年土地利用/覆盖变化的主要特征,这在一定程度上影响着区域生态系统的调节功能.但在2000s初期,这种状况有所改观,表明国家自20世纪末期开始实施的退耕还林还草等一系列生态环境建设措施在一定程度上开始发挥作用;(2)从1983～2001年,中国北方13省的耕地重心整体上表现出向西南方向偏移的趋势.此外,地形和交通状况对耕地的空间变化过程影响明显,区域耕地面积主要集中在海拔较低、坡度较小的平原和丘陵地带,耕地利用强度一般随着距交通干线距离的增加而减少;(3)人们生活收入水平以及农业产量变化与耕地变化关系密切,其中人们生活收入水平与耕地面积成负相关,而农业产量与耕地面积呈正相关,表明经济的发展以及人们生活水平提高导致的非农用地量增加以及农业用地内部的结构调整是中国北方13省耕地变化的重要原因.

Based on the long-term serial NOAA/NDVI dataset during 1983-1999 and SPOT/VGT dataset in 2001, the land use/cover change information in the 13 provinces of northern China was extracted based on the analysis of the cultivated landscape characteristics at first, then the effects of human activities on cultivated land process were explored by GIS and the driving forces of cultivated land change were investigated. The conclusions can be drawn as follows: (1) The constant increase of weak ecological function land as desert and cultivated land and the decrease of the ecological function land of forest and shrub were the main characteristics of the land use/cover change in the 13 provinces of northern China from 1983 to 1999, which showed the effects on the ecological adjustment function. However, such situations were changed to some extent in the 2000s because of the ecological construction policy of the government. (2) From 1983 to 2001, the Baycenter of cultivated land had the trend to move from northeast to southwest with the topography and transportation situations showing the obvious effect on the cultivated land distribution. It is found that the cultivated land use intensity decreased obviously with the increase of distance from the main communication arteries. (3) The improvement of the people's living standard is closely related with the cultivated land change. The structural adjustment in the agricultural land caused by economic development and the improvement of the people's living standard is the important factor affecting the cultivated land change in northern China from 1983 to 2001.