Research On Relationship Between Ecological Factors And Quality Of Flue-cured Tobacco Leaves In Sichuan Province

Sichuan is the third largest tobacco planting provinces in China currently , with a long history of tobacco-growing and rapid speed of development. Ecological conditions are the most basic elements to the quality of tobacco and the basis and premise to the formation of the positive qualities. Smoking areas in Sichuan have obvious differences in climate characteristics, various soil types, and a huge variation in altitude, so the ecological conditions have a major impaction on the quality formation of tobacco. Proceeded with the analysis from the ecological environment and quality of tobacco leaves. This paper analyzed the meteorology, soil and altitude between different ecological zones in Sichuan province , the main chemical compositions ,and sensory quality of different leaf samples. We studied and explored the relationship between different ecological factors and the major tobacco chemical compositions and sensory qualities of tobacco leaves, provided a theoretical basis on the development of special tobacco in our country , for the same time, provided theoretical support on he adjustment of tobacco and agricultural division in Sichuan province. The main results are as following:1,There were significant differences in quality of tobacco leaves between tobacco from different soil types in Sichuan Tobacco areas. Descending order of Tobacco sensory quality between different soil types were: brown violet clay soil≈brown podzolic violet clay soil > yellow soil≈yellow brown soil > yellow red violet soil> percogenic paddy field > acid violet soil> dark violet soil> cold yellow sand soil.2,Soil nutrients in Sichuan tobacco areas had significant on the chemical composition of tobacco leaves , while not obvious direct impact on the sensory quality. The influence factor on the contents of sugar were mainly soil total P and soluble P, with positive correlation; while the factors effecting phenols and nitrogen compounds were sulfur and boron in the soil, were significant positive relation; There were many factors that affected the contents of K in tobacco leaves. Soil organic matter, soluble P, soluble K, total N, Fe, Zn and S had a very significant positive correlation, while soil pH, soil exchangeable Ca had significant negative correlation with the contents of K.3,Altitude of Sichuan tobacco areas had a significant positive correlation with the contents of reducing sugar, total sugar and K . Tobacco leaves from areas with altitude above 1500m had higher sugar and K content; Altitude had a significant positive correlation with the scores of leaf concentration, quality of aroma , quantity of aroma, aftertaste, offensive odor, irritation. Qualities of tobacco leaves in the areas 1500m～1900m altitude were the best.4,Meteorological conditions in Sichuan tobacco areas had significant impact on the quality of tobacco. Average temperature, daily average temperature≥10℃accumulated temperature, evaporation, rainfall, average relative humidity and sunshine duration all had large effects on the qualities of tobacco leaves.5,The chemical compositions were totally coordination in Sichuan Tobacco, the contents of reducing sugar, total sugar, protein were high slightly, the average values were 25.04%, 29.57%, 9.32% respectively. Total nitrogen, total nitrogen, potassium were suitable, 2.44%, 1.91%, 1.78% respectively. The ratio of sugar/nicotine was 11.04, Mu-value was 3.28 , both of them located in the fitting range of the high quality tobacco.6,Smoking areas in Sichuan were divided into five categories according to clustering major chemical components; Category 1 lies in the southern mountain margin region of the Sichuan Basin, Daxian and Yuanba, including 9 counties (cities), belong to middle-sugar middle-alkali middle-K high-Cl District, flavor from Intermediate partial Fen-flavor to intermediate flavor, mainly intermediate flavor. The score of sensory quality was average; Category 2 was in Wangcang County, belonged to low-sugar low-alkali low-K high-Cl District, tobacco flavor was intermediate, the sensory Quality was on the low side. Category 3 had only a county, Xuanhan. It belonged to low-sugar high-alkali high-K low-Cl District, intermediate flavor , the sensory Quality was poor; Category 4 and Category 5 were similar to each other , they lied in the mountain areas in southwestern Sichuan Province, were high-sugar middle-alkali middle-K middle-Cl District , including two cities Liangshan and Panzhihua, 11 counties (cities, districts), Dechang , Yanbian etc. Flavor of category 4 contained intermediate type, Intermediate partial Fen-flavor and Fen partial - Intermediate flavor , mainly Intermediate partial Fen-flavor . The main flavor type of category 5 to tobacco leaves were Intermediate partial Fen-flavor and Fen partial - Intermediate flavor . Sensory quality evaluation of the two categories of were better, with higher score. descending order of total sensory quality score in 5 Categories tobacco leaves: Category 4≈Category 5 > Category 1 > Category 2 > Category 3.7,The chemical components and sensory quality Sichuan Tobacco leaves had significant and regular relationships. Apart from chlorine, the other chemical components reached significant correlation with sensory quality indicators .