Evaluation of tobacco-planting soil quality using multiple distinct scoring methods and soil quality indices

The economic significance of flue-cured tobacco in China relies heavily on soil quality, directly affecting yield and sustainability. However, human activities and climate change have led to soil quality deterioration. Therefore, assessing soil quality in tobacco-planting soil has become imperative. Herein, a total of 177 soil samples were collected from the representative tobacco-growing areas in Qiannan, Guizhou. Twenty-four soil physical, chemical, and biochemical indicators were determined and compiled as the total data set (TDS). The minimum data set (MDS) was formed through the principal component analysis (PCA) and norm value. These two data sets were applied to calculate the soil quality of this region by combining multiple approaches, including three scoring methods and three soil quality indices (SQIs). Linear analysis between MDS and TDS showed that R2 values ranged from 0.617 to 0.762, suggesting the MDS can represent the TDS. Likewise, the MDS, integrated with the non-linear method (NL) and weighed addictive soil quality (SQIw) (SQIw-NL-MDS) and the TDS, integrated with NL and SQIw (SQIw-NL-TDS) exhibited the highest R2 value. The SQIw-NL-MDS model was the best approach to assess soil quality in subsequent analysis. According to the SQIw-NL-MDS model, this region exhibited moderate soil quality. This study preliminarily developed a soil quality assessment model for the tobacco-growing soil in Qiannan region, which might provide theoretical guidance for other key tobaccogrowing areas.