| Tobacco in Yunnan have been providing the most important raw material to Chinese cigarette for long years. Aimed at the main effect factors on tobacco cultivation and quality formation, zonization on ecological adaptability of tobacco plantation in Yunnan has been carried through in order to cooperate with the new zonization throughout China, resolve the problems during production, and ensure the continuable development of tobacco. In this study, many data were used, concerning tobacco leaf's chemical ingredient from 565 cultivated loci, weather results every month from station during the study, historic information from 197 weather station and 513 hydrological station at home and abroad, 683 soil samples in 2005 and the data of soil in Yunnan, the analysis of landform and physiognomy in Yunnan and other data related to tobacco plantation. And some modern analyzing technologies were adopted, including systemic clustering anlysis from statistics, the anylysis of grey association degree, GIS analysis, GPS orientation, etc. The final aim was, to offer scientific decision-making warranty for tobacco-planting layout and improving tobacco-leafs quality as well as establishing planting bases for specially appointed tobacco leaves in Yunnan province. The research paper tried to make clear the main climatic factors dominating and affecting tobacco-leaf's quality in Yunnan, demonstrate the climatic suitability for tobacco-planting, and implement the tobacco-planting partition related to climate, soil and landform and physiognomy based on GIS and tobacco-leaf's quality in Yunnan province. The main conclusions for the research were shown as follows:(1)The difference of distribution and matching of sunshine, temperature and rainfall, which was in the uprightness, region or period of time, together lead to the complicated climate of tobacco in Yunnan. There were remarkable difference in the climatic uprightness in Yunnan. In lower region of tobacco, the temperature was ascendant while upper zone of tobacco was restricted from lower temperature. In middle zone of tobacco, the less quantity of heat was obviously disadvantageous factor. There were remarkable regional difference about sunshine and rainfall. Thereinto, west, southwest-, southeast- Yunnan and northern upper zones were repectively provided with peculiarity. There were also different distribution and matching between sunshine, temperature and rainfall. The difference in sunshine and rainfall were more obvious than in temperature. The change orderliness of quantity of heat in the uprightness. In every layer of quantity of heat, there were higher and lower zone in rainfall and sunshine.(2)Yunnan climates are different from domestic and overseas tobacco planting areas, which are inimitable in temporal distribution and matching for sunshine duration, temperature and rainfall. The climatic singularity in Yunnan includes: more sunshine duration, less rainfall with upper average temperature during growing prophase of field tobacco while contrary climatic conditions come forth during anaphase of field tobacco; In addition, straight sunshine can improve the availability of air temperature for tobacco in Yunnan, which have been proved to be positive correlated with sunshine duration. The zones producing quality tobacco leaves have higher availability. These peculiarities in tobacco climates determine that countrywide tobacco climatic partition indexes are not suitable for tobacco planting in Yunnan. It have been proved that three factors could be used to build up zonization index system in Yunnan, including average temperature in July, the rainfall between April and September and sunshine duration between July and August. For the first time, zonization of ecological adaptability of tobacco plantation throughout Yunnan province have been realized by reckoning and simulating the temporal and spacial distribution of the indexes every month, based on the data from weather station, hydrological station and historical investigation.(3)Climatic predominance for tobacco in Yunnan showed that, more sunshine duration, less rainfall with upper average temperature during early field growing period, and less sunshine duration, more rainfall, moderate temperature with matching well between them during middle field growing period. The characteristic not only improved the sugar content and sugar-nicotine ratio of tobacco leaves, but also restrained the production of tobacco leaf's nicotine, protein and total nitrogen to a certain extend. But climates in late field growing period decreased the accumulation of full-flavor matters and efficiently reduce the transferring and decomposition of organic matter (including tobacco leaf's protein and total nitrogen content). The peculiarities dominated light-flavor style for tobacco leaves with high sugar, moderate nitrogen and less petroleum ether extract.(4)Although the regions of tobacco cultivated in Yunnan were across several climatic zones and great range of altitude, yet high-grade tobacco could be all produced, which were be resulted from lower-temperature in altiplano of low-latitude in summer, tending to be identical of average temperature in July, the positive correlation between the availability of temperature and sunshine duration during metaphase and anaphase of field tobacco, cultivation techniques for film mulching, etc.(5)Through classifying chemical quality classes of tobacco leaves in Yunnan with systematic cluster analysis method, it were clearly put forward that there were four chemical quality classes of tobacco leaves. That is, more sugar-less nitrogen (nicotine)-less petroleum ether extract (type I ), much sugar-ounce nitrogen (nicotine)-thin petroleum ether extract (type II). The main classes produced are type I and type II. Most parts of central Yunnan belong to most suitable area or average suitable area where tobacco leaves of quality type I (light-flavor) are produced, including Yuxi, Honghe, Qujing, Chuxiong, Kunming and the east of Dali. Most areas in southwest Yunnan are the sub-suitable area or average suitable area where tobacco leaves of quality type II are yielded.(6)Employing grey association degree analysis with annual average climatic grid values from simulation and the tobacco climatic patterns relevant to classified chemical quality classes of tobacco, the GIS-based climatic partition for tobacco leaf's quality was implemented. The two tobacco climatic partitions from different methods showed consistency and objectivity in divisional results. Their results not only reflected the relationships between tobacco climatic suitability grades and the pros and cons of tobacco leaf's quality, but also incarnated the intrinsic relations between climates and quality style traits of tobacco leaves in Yunnan. Meanwhile, the research paper enhanced the practical guidance of tobacco-planting climatic partition on the production of tobacco leaves.(7)pH, organic matter, and types of tobacco cultivated soil were confirmed as the evaluation index. Finally, the general appraisal system of soil suitability in Yunnan was constructed after weight analysis. The results suggested that the soil adapted to plant tobacco distributed in every canton of Yunnan. Thereinto, the best places were centralized in Chuxiong, Honghe, Kunming, Yuxi, Qujing, Zhaotong, Dali. Baoshan, Wenshan, Linchang, were the secondary place.(8)Combined with the inimitable geographical background, grade and slope orientation were reduced to three leading factors of landform and physiognomy, after weight analysis and evaluation on the precision of data. Integrate grade and qualitative evaluation on the adaptability of landform and physiognomy of tobacco in Yunnan was finally constructed, based on digital elevation model (DEM) from mapping department. The results suggested that middle latitude was the best adaptable area, mainly distributing in east-Yunnan, including Kunming, Honghe, Qujing and Wenshan. Secondly with Chuxiong, Zhaotong, Dali, Baoshan. The results above were consistent with the distribution of traditional tobacco plantation area. |
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