干旱区生态环境知识资源中心

Rapid landscape pattern change has taken place in many arid and semi-arid regions of China such as Yellow River Basin over the past decade. In this article, the physical suitability of cropland and its change were evaluated and analyzed by the combined use of satellite remote sensing, geographical information system, and landscape modeling technologies. The aim was to improve our understanding of cropland change so that sustainable cropland utilization could be established. First, the spatial pattern change of cropland was analyzed using the 1-km(2) area percentage model; second, the numerical model for cropland suitability assessment was explored and developed using analytical hierarchy process analysis method. Using this model, cropland suitability index was computed for the whole of the basin from 1990 to 2005. The cropland suitability index was classified into five levels: better, good, middle, bad, and worse, following the natural breaks classification. The spatial distribution of cropland suitability level and its changes over the 15 years from 1990 to 2005 were analyzed and the driving factors of cropland change were investigated. The results showed that the cropland suitability in the study area was at good level, and the cropland quality had been gradually improved on the whole. However, the cropland quality had become worse over the 15 years in some regions. In the study area, governmental policies for eco-environmental protection and population growth were found to be the major factors that caused the cropland change over the past 15 years.