Mapping Cropland Abandonment in Mountainous Areas Using an Annual Land-Use Trajectory Approach

Abstract

In recent years, with the unceasing acceleration of China’s urbanization and rapid development of the country’s economy, cropland abandonment has become an ongoing issue, especially in mountainous areas. Mapping abandoned cropland using remote sensing technology is still challenging due to the difficulties in distinguishing abandoned cropland from fallowed land. In addition, there are few credible approaches to map timing and recultivation of abandoned cropland. In this context, this research developed an annual land-use trajectory approach to map different types of abandoned cropland based on freely available Landsat and HJ-1 satellite images with a spatial resolution of 30 m. Based on this method, five types of cropland change, including one type of fallowed land and two types of abandoned land, were identified in a mountainous town of China (Zhongduo). In addition, the timing and recultivation of abandoned cropland were assessed. The accuracy of the abandonment map was assessed as high as 86.67%. It was found that the percentages of spontaneous abandoned, induced abandoned, fallowed, stable, and lost cropland in Zhongduo were 23.16%, 8.40%, 13.69%, 27.84%, and 26.91% from 2012 to 2017, respectively. The average time for spontaneously abandoned cropland was 3.45 years. Furthermore, 50.54% of the spontaneously abandoned cropland and 12.91% of induced abandoned cropland were recultivated due to fluctuating prices of agricultural products and materials, and the implemented land transfer policy.