Abstract:

To investigate the soil texture conditions in the Changsha tobacco region and their effects on flue-cured tobacco yield and quality, this study selected 401 representative field plots across the area. Through soil surveys, field sampling, and laboratory analysis, the authors evaluated soil nutrient status, economic characteristics of flue-cured tobacco, and conventional chemical composition of tobacco leaves over three consecutive years for different soil textures, and analyzed their interrelationships. The results showed that clay and loam-clay soils were predominant in the Changsha tobacco region, while loamy soils accounted for a smaller proportion. Soil pH, organic matter, available nitrogen, effective phosphorus, and rapidly available potassium levels were generally suitable; total nitrogen was moderate, total phosphorus relatively low, and total potassium highest in loamy soils. Tobacco grown in clay soils yielded the highest production and value, whereas yields and proportions of top-grade tobacco were relatively lower in loamy soils. Chemical compositions of upper and middle leaves from different soil types mostly fell within desirable ranges. Specifically, total sugar and reducing sugar contents in upper leaves ranked as loamy > loam-clay > clay soils. Flue-cured tobacco grown in loamy soils had the highest total nitrogen and total potassium content. In middle leaves, total sugar content was slightly higher in loamy soils, while sugar-alkali ratio, nitrogen-alkali ratio, and potassium-chlorine ratio were mostly within optimal ranges. Overall, the balance of chemical composition in tobacco leaves varied by soil texture, ranking as clay > loam-clay > loamy soils. Tobacco leaves grown in clay soils in the Changsha region exhibited the best compositional balance, indicating that clay soils have great potential to become a key tobacco-growing soil type in this region.

Key words: tobacco-planting soil, soil texture, nutrient status, yield, quality