Soil Quality Assessment of the Cultivated Land Around the Tailing Ponds in the Qinling Mountains of China

The small area of cultivated land in the Qingling Mountains of China is important for the survival of the local population. The soil quality in the area has declined dramatically in recent decades due to the exploitation of mineral resources and unreasonable land management. This study estimates the level and spatial distribution characteristic of soil quality using the minimum data set (MDS) and total data set (TDS) methods. We then verify the reliability of the result using the MDS method in the cultivated land around the tailing ponds in the Qinling Mountains of China. A total of 32 soil samples were collected in the cultivated land around the four tailing ponds and 15 indicators comprising the soil chemical, physical, and heavy metal properties were analyzed. The key indicators of soil quality were soil organic matter, total nitrogen, total phosphorus, $${\text{NH}}_{4}^{ + }$$ -N, soil water content, and Zn. These indicators were screened by principal component analysis and the norm value method. The soil quality index (SQI) determined using the TDS method (0.29–0.52, 0.40 average) was lower compared to that of the MDS method (0.25–0.65, 0.42 average). The spatial distribution pattern of soil quality indicated a fluctuating trend for SQI, with values increasing with the distance from the tailing ponds. The 1 : 1 line was employed to test the accuracy of the MDS results, with a coefficient of certainty of 0.999 and a coefficient of relative deviation of 0.057. This proves the ability of the MDS method to assess the cultivated soil quality around the tailing ponds in the Qinling Mountains. The results indicate that to realize agricultural sustainability, effective soil quality improvement measures, (e.g., mulch cover, no-till farming, and organic fertilizers) should replace current traditional cropland management measures in the cultivated land around the tailing ponds of the Qinling Mountains.