Study On The Relationship Between Major Ecological Factors And Cigar Leaf Quality In Sichuan

Based on the meteorological data and soil sample analysis materials in Sichuan cigar growing area,the climatic characteristics and soil nutrient suitability of Sichuan were systematically evaluated by using the method of numerical processing and analysis software;Then,based on the principle of one-to-one correspondence,the relationship between major ecological factors and cigar leaf quality was analyzed by using simple correlation analysis method and partial least square method,and the importance of ecological factors affecting cigar leaf quality was ranked.The main conclusions are as follows:1.The meteorological conditions in Sichuan cigar planting area have the characteristics of field temperature,≥10℃ accumulated temperature and appropriate sunshine hours,which are conducive to the growth,development,maturity and yellowing of cigars.The average temperature,the highest temperature,the lowest temperature and the ≥10℃ accumulated temperature in each growth period in the cigar growing areas of Sichuan increased gradually from root extension stage to maturity stage,and there were significant differences among regions,among which the heat condition in Xuanhan area was the best;The temperature difference between day and night and sunshine hours in field growth period were significantly different among regions,which showed that Deyang area was significantly lower than Dazhou area;There are significant differences in total precipitation between regions in maturity and growth period,especially in Wanyuan of Dazhou.The total precipitation in growth period is770.60 mm,which is significantly higher than that in other areas,but there is no significant difference between regions in root extension period and prosperous period;The average relative humidity in each region gradually increases from root extension stage to maturity stage.More precipitation and higher average relative humidity in maturity stage are unfavorable to the later growth and airing of cigars,which has also been proved in actual production.In order to better adapt to the local climatic conditions,the optimal growth environment can be obtained under more suitable climatic conditions by adjusting the transplanting time.2.The pH value of tobacco planting soil in Deyang and Dazhou in Sichuan cigar planting area is 84.84%,which is within the appropriate range.There is no strong acidic and alkaline soil,and the overall variation is small;The contents of soil organic matter and total nitrogen were not very high,both in the moderate and slightly low range,and the proportion of unsuitable was only 28.94% and 11.55% respectively;The content of available phosphorus in tobacco growing soil in Sichuan is high and varies greatly,and it is distributed in more unsuitable areas.Among them,the proportion of unsuitable areas in Shifang area is as high as46.05%,and that in other areas is slightly lower,and the overall average proportion of suitable areas is 67.9%;The spatial distribution of soil available potassium content is quite different.The proportion of Dazhou area is higher than that of Deyang area,the proportion of Deyang unsuitable area is higher than 50.0%,but the proportion of Dazhou unsuitable area is only17.3%.The content of available potassium in each area is at a medium to low level,which can be adjusted by increasing potassium fertilizer;The content of water-soluble chlorine in Sichuan soil is generally low,accounting for only 1.52% in the most suitable range of 10mg/kg ~ 30 mg/kg,17.34% in the sub suitable range of 3 mg/kg ~ 60 mg/kg,while the tobacco planting soil in the unsuitable range accounts for 81.14% of the total.Especially in Wanyuan area,this situation is the most serious,and the unsuitable proportion is as high as 91.78%.Chlorine fertilizer must be supplemented to improve the content of water-soluble chlorine in soil.3.According to the principle of one-to-one correspondence,through the analysis of the relationship between climate,soil factors and conventional chemical components and sensory quality of cigar tobacco leaves,it is considered that:(1)precipitation in maturity,average relative humidity,sunshine hours and temperature,soil p H,organic matter and water-soluble chlorine are important factors affecting the conventional chemical components of Sichuan cigars.In terms of meteorological factors,reducing sugar,nicotine,potassium content and potassium chloride ratio are closely related to meteorological factors.The total sunshine hours in root extension period and growth period are significantly positively correlated with potassium content,the long-term sunshine hours are significantly negatively correlated with reducing sugar,the precipitation and average relative humidity in mature period are extremely significantly negatively correlated with nicotine,and other chemical components are also significantly correlated with climate factors in varying degrees.In terms of soil factors,soil p H has a very significant positive correlation with total nitrogen,nicotine and chlorine,and a very significant negative correlation with potassium,sugar alkali ratio and potassium chloride ratio.Soil available phosphorus,available potassium and water-soluble chlorine have different degrees of significant correlation with reducing sugar nicotine,potassium and chlorine,while soil water-soluble chlorine has a very significant positive correlation with chlorine content in tobacco leaves,and water-soluble chlorine has a very significant negative correlation with potassium chloride ratio.(2)The average temperature at maturity,the average relative humidity at growth stage,the accumulated temperature at maturity and water-soluble chlorine are important factors affecting the sensory quality of Sichuan cigars.In terms of meteorological factors,with the increase of sunshine hours,the aroma quality,aroma quantity and dryness showed a significant downward trend,while the scores of alcohol,miscellaneous gas and aftertaste increased significantly;With the increase of precipitation in the growth period,the degree of alcohol,fineness,softness and ash setting showed a significant downward trend.The average relative humidity had a strong correlation with the degree of alcohol,miscellaneous gas,fineness and softness.In addition,the daily average temperature in the field period,the temperature difference between day and night and the accumulated temperature ≥ 10℃ had a significant correlation with the characteristics of flue gas and combustion;As far as soil factors are concerned,the correlation analysis results between soil factors and sensory quality show that soil factors are closely related to the aroma characteristics of tobacco leaves.Soil p H,soil available potassium,available phosphorus and water-soluble chlorine are significantly related to aroma temperament,aroma quantity,penetrability and aroma richness.Flue gas characteristics have little relationship with soil factors,and the taste characteristics are greatly affected by available potassium and watersoluble chlorine,It has a very significant positive correlation with water-soluble chlorine,a significant positive correlation with soil p H and water-soluble chlorine,and a very significant negative correlation with available phosphorus.4.On the basis of simple correlation analysis,this paper further analyzes the relationship between climate,soil factors and chemical composition and sensory quality by using partial least square method.The results show that:(1)different ecological factors have different effects on each chemical composition index of cigar tobacco leaves,and meteorological factors have a great influence on it,such as precipitation,average relative humidity,sunshine hours and temperature in the middle and late growth stage;Soil factors such as soil p H,organic matter and water-soluble chlorine have a great impact on it,and the importance coefficient VIP ranks first,which is consistent with the results of simple correlation analysis and typical correlation analysis.(2)The main influencing factors of sensory quality in Sichuan cigar areas are average temperature in mature period,average relative humidity in growth period and accumulated temperature in mature period.The influence of air temperature on it is mainly concentrated in the prosperous period and mature period of tobacco growth.The relative humidity in the prosperous period and later mature period is most closely related to the quality,and the water-soluble chlorine in soil has a great impact on the sensory quality.