Spatiotemporal variations of freeze-thaw erosion risk during 1991-2020 in the black soil region, northeastern China

Freeze-thaw (FT) erosion, which occurs in high-altitude and high-latitude regions, has a considerable impact on water and wind erosion. However, studies on long-term variations of FT erosion induced risks are still limited. In the present study, based on 30-year data at 247 meteorological stations, spatiotemporal FT erosion risk in the black soil region, northeastern China was evaluated through the Analytical Hierarchy Process (AHP) and Entropy-weight method (EWM). Six FT erosion-related variables, including annual FT cycle days, soil water content (SWC), fraction vegetation coverage (FVC), slope, soil bulk density (BD), and soil structural stability (SSI) were used to assess FT erosion risk in the study region. Among these variables, the slope was the most important variable (45 %), followed by annual FT cycle days (15 %), FVC (15 %), and SSI (14 %). FT erosion risk differed in different land use types. Woodland, residential land and grassland suffered severe FT erosion risk, and paddy and dryland suffered slight FT erosion risk. Complex topography areas had a higher FT erosion risk. During past 30 years, global warming mitigated the FT erosion risk. This study can help understand soil erosion characteristics and soil loss control for the Chinese black soil region and similar regions in the world.