Abandoned cropland: Patterns and determinants within the Guangxi Karst Mountainous Area, China

摘要

Cropland abandonment because of rural depopulation or policy interventions has become a key issue in Chinese mountainous areas. One such region is the Guangxi Karst Mountainous Area (GKMA), a zone where more than 59% of total land area is hilly. Although depopulation and declining agriculture since 2000 within the GKMA have led to vast areas of abandoned cropland, the spatiotemporal distribution that underlies this pattern as well as its causes remain little understood. We therefore estimated the extent of cropland abandonment since 2001 within this region using land use trajectories derived from Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) data alongside phenology metrics. The results of this analysis show that 4.89% (0.56 x 10(4) km(2)) of land within the GKMA has been abandoned since 2001. Specifically, within four sub-periods (between 2001 and 2005, between 2005 and 2010, between 2011 and 2015, and between 2016 and 2019), overall trends were characterized by an initial increase and then slight decrease in cropland abandonment rate (CAR); 10.67%, 14.71%, 23.13%, and 21.26% over these time periods, respectively. Data also show that CAR spatial distribution tends to be similar to adjacent areas. We then utilized a geographical detector model (GDM) and Spearman correlation analysis to assess the effects of environmental and socioeconomic variables on cropland abandonment patterns. Data show that environmental factors have generally exerted a more significant effect on cropland abandonment within the GKMA than socioeconomic variables. Interactions between determinants have also either exerted non-linear-enhanced or bi-enhanced effects on cropland abandonment over time.