Evaluation and Correlation Analysis of Soil Nutrients and Chemical Constituents of Tobacco Leaves in Meizhou Tobacco Production Area of Guangdong

【Objective】The study aims to explore the traits and their correlation of soil and chemical constituents of tobacco leaves in Meizhou tobacco production area of Guangdong, and explore the key soil factors affecting the chemical quality of tobacco leaves.【Method】48 tobacco-planting soil and the corresponding middle and upper flue-cured tobacco leaves were collected to analysis the traits of soil and chemical constituents of tobacco leaves. Stepwise regression analysis was used to explore the key soil factors influencing the chemical constituents of tobacco leaves.【Result】In the tobacco-growing soil of Meizhou tobacco production area of Guangdong, the proportion of low soil pH value accounts for 64.58%, the content of organic matter (SOM) and water-soluble organic carbon (WSOC) are rich, the appropriate proportion of total nitrogen (TN) content accounts for 68.75%, the rich and extremely rich proportion of total phosphorus (TP) content accounts for 70.83%, the deficient and extremely deficient proportion of total potassium (TK) content accounts for 68.75%, and the rich and extremely rich proportion of available nitrogen (AN), available phosphorus (AP) and available potassium (AK) account for 97.92%, 91.76% and 79.17%, respectively. The content of total sugar, starch and sugar alkali ratio in the middle tobacco leaves were higher, accounting for 91.67%, 100% and 66.67% respectively; the content of total sugar, reducing sugar and starch in the upper tobacco leaves were higher, accounting for 87.50%, 75.00%, 100% and 56.25% respectively; the content of nicotine was lower, accounting for 47.92%. The results of principal component analysis showed that sugar alkali ratio, total nitrogen, nicotine, total sugar and reducing sugar content were the main indicators for evaluating the chemical constituents of middle tobacco leaves, and reducing sugar, sugar alkali ratio, total sugar and nicotine were the main indicators for evaluating the chemical constituents of upper tobacco leaves. Comprehensive chemical quality of middle tobacco leaves was positively correlated with soil AK content, nicotine content in middle tobacco leaves is negatively correlated with soil AK content, the contents of total sugar, reducing sugar and starch in middle tobacco leaves and starch in upper tobacco leaves are negatively correlated with the content of soil WSOC, the content of reducing sugar in upper tobacco leaves is positively correlated with soil AP; the comprehensive chemical quality of upper tobacco leaves was negatively correlated with soil AP content, and positively correlated with soil AK content and pH value.【Conclusion】Improving the soil pH value, AK and WSOC content and reducing the AP content in soil is beneficial to improve the quality of Meizhou tobacco leaves.