Climate Similarity Analysis on High-quality Flue-cured Tobacco Planting Areas in North Central Subtropical Zone of China

The climate data of 180 meteorological stations from 1991 to 2020 are analyzed, representing different flue-cured tobacco planting areas in north central subtropical zone of China. The latest growth period division method and the latest tobacco varieties are considered, and the key growth period indicators of high-quality flue-cured tobacco are obtained through field investigation. According to the climatic conditions affecting the growth and development of high-quality tobacco leaves, the characteristics of the main climatic factors such as temperature, sunshine duration and precipitation in the field period and each development periods including root extension period, vigorous growing period and mature period are statistically analyzed. The weight of climate factors is calculated with principal component analysis method. Based on the principle of climate similarity, the similarity analysis is carried out by using the improved Euclidean distance between the two major tobacco planting areas of Hubei Province and the surrounding tobacco planting areas. The clustering results are obtained by hierarchical cluster method. The results show that the climate factors such as temperature, precipitation and sunshine duration meet the climate conditions for the growth of high-quality tobacco in the planting areas of southwest Hubei, northwest Hubei, western Henan, southern Henan, central Henan, western Hunan and central Hunan, compared with other tobacco planting areas. The difference of other climatic elements in different development periods is the largest in the root extension period, then in vigorous growing period, and is the smallest in the mature period except for precipitation. The climate elements in different development periods of tobacco planting areas are moderate in northwest and southwest Hubei, which is suitable for the growth and development of high-quality tobacco. Among the climatic factors affecting the growth and development of tobacco leaves, the temperature maximum in the prosperous period has the greatest impact on the growth and development of tobacco leaves. By comparing and analyzing the climate similarity of high-quality flue-cured tobacco areas in north central subtropical zone of China with two methods, the consistent conclusion is drawn. The climate elements of the tobacco planting areas are the closest in northwest Hubei and southern Shaanxi, and the climate elements of the tobacco planting areas are highly similar in southwest Hubei and western Hunan and southeast Sichuan. The results provide theoretical basis to optimize the layout of flue-cured tobacco planting and develop exclusive high-quality tobacco.