Land use/land cover change and soil property variation increased flood risk in the black soil region, China, in the last 40 years

Land use/land cover change and soil property variation driven by agricultural development substantially affect hydrological processes. Although previous studies have shown that land use/land cover change increases flood risk, how much soil property variation contributes to changes in water yield remains unclear in large-scale regions. Quantifying the water yield response to long-term land use/land cover change and soil property variation in agricultural regions is critical for flood risk control. The black soil area in China was chosen as the study area, and land use/land cover change, soil property variation, and changes in water yield during 1980-2020 were estimated. Land use/land cover change and soil property variation scenarios were established to separate the contributions of land use/land cover change and soil property variation to changes in water yield. The results showed that cultivated land and urban land expanded from 1980 to 2020. The plant available water capacity decreased by 2.10% and 7.27% in the black soil area and typical black soil area, respectively, and the water yield increased by 5.52% and 8.49% in the black soil area and typical black soil area, respectively. Land use/land cover change and soil property variation accounted for 58.64% and 36.67% of the increase in water yield in the black soil area. However, in comparison to land use/land cover change (47.40%), soil property variation (48.77%) accounted for a larger portion of the increase in water yield in the typical black soil area. Both land use/land cover change and soil property variation increased flood risk, however, the effects of soil property variation may exceed those of land use/land cover change, as determined by the spatial scale. This study can provide important information for land use planning and soil hydrological property improvements to reduce flood risk.