Soil Degradation of Sloping Cropland in the Typical Black Soil Region in Northeast China: Risk Assessment and Uncertainty Analysis

Soil degradation in the typical black soil region in Northeast China poses a threat to agricultural productivity and sustainability. However, little is known about the distribution of soil with different degradation degrees on a regional scale. This study aimed to map soil degradation status based on a newly developed soil degradation index (SDI) and assessed the uncertainty of degradation risk through the combination of ordinary Kriging and sequential Gaussian simulation (SGS) in order to enhance the accuracy and credibility of predictive results. The mean SDI was 0.445, with a coefficient of variation of 30%. The realization with 200 times by SGS was the best showed an increasing pattern of soil degradation degree from north to south in the study area. Slightly and moderately degraded sloping cropland accounted for 35.3% and 52.4% of all sloping cropland, respectively. High-risk areas were mainly located in the Daxing'an and Changbai Mountains to the Songnen Plain. Proactive measures are necessary to control and mitigate further degradation by improving soil management and weakening the impact of runoff on sloping cropland. The developed risk assessment maps provide baseline information for regional sustainable development.