Research On The Relationship Climate And Soil With Tobacco Quality In Tobacco-Growing Areas In Chongqing

Tobacco is an important kind of leaves with economic crops and its growth and quality are highly relavant with ecological factors. The desciplines and features can be formed in the mutual effect between tobacco and soil, climate and terrain factors. This research focuses on the interaction between tobacco quality and climate factors, soil and altitudes, in virtue of the determination of varieties of soil, climate, terrain and tobacco quality index and statistics including correlation analysis and regression analysis, path analysis. The effect of rainfall capacity, sunshine duration, effective accumulated temperature and average relative humidity on tobacco quality, yield value, plant disease and physics property, as well as the mutual relathionship are showed and explained in the experiment of climate resources allocation. By means of correlation analysis and path analysis, the allocation law of climate resources content of tobacco with distinctive yield values is illustrated. Meanwhile, this research also explaines the relationship between climate factors and tobacco quality, and variation of tobacco chemical components with that of climate conditions. In addition, the influence of soil factors on tobacco quality and relationship between soil ecology and tobacco quality are analyzed and illustrated by means of collecting data of soil nutrient content and tobacco chemical components in382tobacco-planting sites. In virtue of recording different altitudes data in tobacco-growing areas, and variation analysis and multiple comparison among tobacco chemical components in different altitudes in Chongqing displays the variation of tobacco chemical components with that of altitudes and mutual relathionship between altitudes and quality index of tobacco leaves, as well as whether chemical components contents in suitable range.The results of field experiment show that different transplanting time has large effect on the development and yield of tobacco. If the transplanting time is too in advance, then rainfall capcity would be in excess demand in vigorous stage,190millimetres higher than that of normal transplanting time, and deficient in glomorous and mature stage,54millimetres lower than that of control group in glomorous stage and92millimetres lower in mature stage. Sunshine hours would be too long in mature stage,78hours higher.The unbalanced allocation of rainfall capacity in the whole developmental phase and exceeding sunshine hours in mature stage result in inappropriate enlonging duration of developmental phase, which also further lead to the late-maturing of tobacco-leaves which are too thick and with high peduncle-rate. Exceeding rainfall capacity in vigorous stage results in remarkably low leaf area index. The yield and yield value are reduced a great deal in the end, yield666kg/hm2than that of normal transplanting time, yield value14672yuan· hm-2lower. If the transplanting time is too late, the accumulating temperature and rainfall capacity would be too high in mature stage,47millimeter higher than that of normal transplanting time, and deficient in vigorous stage, sunshine hours too long in glomorous stage,42hours higher than that of normal transplanting time, which further gives rise to a fact that the duration of developmental phase is cut down and low single-leaf weight, thin leaf, exceeding ratio of potassium to chlorine. In the end, the yield and yield value are much lower than that of routine transplanting time. However, in normal transplanting time, the optimum yield and yield value can be obtained and tobacco develops well due to low incidence of mosaic and fine physical quality resulted from relatively low accumulative temperature in glomorous stage and high accumulative temperature in vigorous stage, main distribution of rainfall capacity in vigorous stage. With the transplanting time too in advance, rainfall capacity in vigorous stage is exceeding and accumulated temperatures deficient, which blocks the transformation of nitrogen into nicotine and lower the content of nicotine. In the treatment of early transplanting time, content of nicotine in upper leaves only takes advantage of50.7%of that in control group,58.3%in lower leaves, and fall short of appropriate range. Besides, low accumulative temperature in vigorous stage leads to the hinderance of composition for nutritional objects, which further results in the the content of total sugar lower by17.5%compared with that of control group in upper leaves,18.0%in middle leaves and23.3%in lower leaves.With the lagging transplanting time, accumulative temperature is so exceeding in glomorous stage and deficient in mature stage, rainfall capacity too large in mature stage, which has disadvantageous effect on the transformation of nitrogen to nicotine. If20days later normal transplanting time, nicotine in upper leaves is reduced by56.9%than that of control group, in middle leaves22.1%, in lower leaves46.3%, all of whose nicotine content is not among suitable scope. Besides,20days later, the content of total sugar is33.1%lower than that of control group in upper leaves,20.5%lower in middle leaves,31.9%lower in lower leaves, and content in middle and lower leaves is below the suitable scope. The variation of climate resources allocation leads to the significant change of tobacco quality, yield value, physics property, disease rate, duration of growing period and biological properities due to different transplanting time. The best transplanting time is the one tillers used to follow, which means climate resources allocation in this period is the most approriate for tobacco growth and quality forming. Further, by simulating the relative leaf area index and relative climate indexes, the index dynamic model formulation of relative leaf area "y=(a+bx)/(l+cx+dx2)" is established. It is found that when the ratio of accumulative temperature, rainfall capacity and sunshine hour before and after the maximum leaf area forming reach1.44,1.86.2.21, respectively, the highest yield value could be gained. In addition, due to with the ratio of developmental duration before and after the maximum leaf areas in the highest-yield-value tobacco-planting site,1.42, lower than average1.52and normal ratio1.67-1.8, if the harvest time could be in advance or lengthen the duration of mature stage, the allocation of climate resources would become better and help reach the higher value. Then ratio of climate resources contents before and after the maximum leaf area forming could be found out by means of derivation of the equation. The new equation after derivation could be used for calculation of ration of climate resources contents before and after leaf harvestation of beginning in high yield region. The reasonable transplanting time could be arranged based on the climate data in former years, which is instrumental in the improvement of tobacco yield and quality.The correlation analysis between climate factors and tobacco chemical components shows the sufficient accumulated temperature in early growth period of tobacco avails for the formation of sugar in tobacco, but not advantageous for formation of nitrogenous compounds and tobacco potassium. Therefore, in view of climate conditions of tobacco-growing areas in Chongqing, transplanting in mid-to-late May could be helpful for enhancing the ratio of sugar to nicotine and sugar to protein, which could make smoke medium rather than exceedingly strong. The rainfall capacity in late growing period of tobacco is disadvantageous for the formation of nicotine, sugar and potassium. If average relative humidity in late growing period of tobacco is too high, the composition of sugar and nicotine will be hindered. Also, the correlation between climate factors and chlorine is hardly relavant, which illustrates that accumulation of chlorine in tobacco leaves is affected by other factors. After consulting references and investigation, the continuous cropping may be the possible reason for high chlorine content in tobacco leaves.The results of regression analysis and simple correlation analysis on relationship between soil factors and tobacco quality are generally consistent, which shows that wide range of investigation areas in this research rules out occurrence of extreme situation, such as abnormally high or low nutrient content in some regions. The reliability of research results are strenghthened based on extensive research areas. The results show that in different tobacco-planting regions of Chongqing, as soil pH and organic matters content increase, the sugar, nicotine content and ratio of potassion to chlorine increase significantly, the chlorine and potassium content decrease; as soil available iron and available manganese content increase, the sugar, nicotine, chlorine content and ratio of sugar to protein will enhance obviously, but the content of nitrogen, phosphorous and protein will fall; as soil exchangeable calcium and magnesium content increase, the tobacco sugar and protein content will rise remarkably, but phosphorous, chlorine content and ratio of sugar to protein will reduce; as the enhancement of soil water-soluble chlorine ion, the tobacco potassium, ratio of sugar to nicotine, sugar to protein and potassium to chlorine will become quite higher, but tobacco phsophorous content become much lower.The research on the relathionship between altitude and tobacco quality shows that altitude is significantly positively correlative with tobacco sugar, nicotine content and ratio of sugar to nicotine, and negatively correlative with tobacco protein and nitrogen content, but not significantly relative with ratio of potassium to chlorine, sugar to protein, potassium and chlorine content. In tobacco-growing areas of Chongqing, the chemical composition of coordination in tobacco leaves during the range from600to1100meters is the best. As a result, tobacco-growing in these regions should be focused and strenghthened.