Canonical correlation analyses of sub-suitable mineral elements and chemical composition of flue-cured tobacco leaf with soil ecosystem index in Nanyang

Soil ecosystem indexes, leaf mineral elements and chemical compositions of flue-cured tobacco from 13 different ecotypes of Nanyang tobacco cultivation area were analyzed along with 16 high-quality tobacco leaf samples from Brazil and Zimbabwe tobacco cultivation areas. Comparison of mineral elements and leaf chemical compositions from Nanyang and the high-quality tobacco shows that P, K, Ca and Na are the main sub-suitable mineral elements and that nicotine, total sugar, reducing sugar and starch contents are the main sub-suitable chemical compositions of flue-cured tobacco in Nanyang. Canonical correlation between sub-suitable mineral elements, tobacco leaf chemical compositions and soil ecosystem indexes was conducted. The results show that increasing soil Zn (to a certain range) increases reducing sugar while decreasing nicotine content in tobacco leaf. With the reduction of amonifier amount and increment of nitrifier amount in the soil, tobacco leaf nicotine content significantly increases, while total sugar, starch and P decrease. Reducing sugar content of tobacco leaf increases with decreasing soil actinomycetes and increasing silicatebacteria. Ca and Na content of tobacco leaf is highly negatively correlated with soil Cu content. While tobacco leaf Ca content increases, Na content decreases with decreasing amount of soil nitrifier and increasing amount of soil eumycetesr. We conclude that soil, especially soil microbe characteristics, improvement enhances tobacco leaf quality.