Current Research and Perspective of Soil Nutrients Spatial Variation Characteristics in Flue-cured Tobacco Planting Soil in China

A good soil environment helps to ensure the healthy growth of flue-cured tobacco plants, and the nutrients therein profoundly affect the sustainable development of planted tobacco resources. In exploring the spatial variability characteristics of soil nutrients, visualization methods and the construction of a comprehensive soil fertility evaluation system can provide a scientific reference for determining the nutrient content of tobacco planting soil. Using a bibliometric approach, we collected 90 published papers from 2008 to 2022 from the Web of Science and CNKI databases on the spatial variation in soil nutrient characteristics of flue-cured tobacco planting soil, with a focus on the conditions found in China. The current situation and potential issues were analyzed according to the indicator selection frequency, spatial variation visualization method, and influencing factors. There were 20 indicators reflecting the soil nutrients of flue-cured tobacco planting soil. The frequency of available zinc was the highest at 42.86%, followed by phosphorus, organic matter, pH, alkali-hydrolyzable nitrogen, and available potassium. Among the visualization methods, Kriging interpolation was the most widely used, with an application frequency of 68.80%. The influencing factors were divided into natural and human ones. Principal component analysis was commonly used to screen indicators and determine weights, and the soil fertility suitability index was used to evaluate the spatially integrated fertility of soil nutrients for flue-cured tobacco planting. Available zinc, available phosphorus, soil organic matter, soil pH, soil alkali-hydrolyzable nitrogen, and available potassium are important evaluation indices for determining the spatial variability of soil nutrients in flue-cured tobacco planting soil. The selection of indicators, the determination of their weights, and method selection all significantly affect the accuracy of soil nutrient evaluation; thus, future work should focus on the development of a comprehensive evaluation system for tobacco planting soil that also considers trends associated with natural and human factors and their effects on spatial variability.