| Flue-cured tobacco is an important cash crop in China,and its yield and quality are affected by ecological environment.The Liangpan tobacco growing area is the main tobacco producing area in Sichuan.The environment in this area is complex,and the soil,climate and other factors show obvious differences,which affect the quality of tobacco leaves in this area.Therefore,it is necessary to study the spatial distribution characteristics of ecological factors in Liangpan tobacco growing areas.On this basis,the influence of ecological factors on the quality of tobacco leaves is analyzed,and then the main ecological factors are identified and appropriate intervals are extracted.This study used the 494 flue-cured tobacco samples(C3F)from 27 counties and districts in Liangpan tobacco growing areas of the year 2007-2013 as materials to analyze the appearance,chemical and sensory quality.And used the inverse distance weighted interpolation method(IDW)to analyze the spatial distribution characteristic of tobacco quality.Collected 1658 soil samples,and analyzed the soil nutrient contents such as SOC,pH,AN,AP and AK.Then the use of HASM EF on the spatial distribution of soil nutrients were studied.The use of Liangpan area and 37 meteorological stations around the years(1981-2013 years)meteorological monitoring data,remote sensing and digital elevation model(DEM)data to simulate the spatial distribution of main meteorological factors from from April to September by using HASM mathematical modeling techniques.Based on the DEM data of Liangpan tobacco growing area,the topographic factors(altitude and slope)which have important influence on the growth and development of flue-cured tobacco were extracted,and the topographic and environmental conditions of the cold climbing area were analyzed.On this basis,the ecological factor data of the corresponding tobacco leaf samples were extracted,and the correlation between the different ecological factors and the quality of tobacco leaves were analyzed,and the partial least squares regression model(PLR)was used to identify the major ecological factors in Liangpan tobacco growing areas,the fuzzy C means clustering method was used to extract the appropriate intervals of the major ecological factors.The main results were as follows:(1)The quality of tobacco leaves in Liangpan tobacco growing area was statistically analyzed,and the spatial distribution map of tobacco quality was obtained by using IDW interpolation method,and the pictures were obtained.The appearance quality,color was ranging at the "lemon yellow" and "orange",maturity was ranging at the "ripe",mature leaves was ranging at the "loose structure",identity to slightly thin and slightly thick,with oil,chroma.The analysis of the total score,color,maturity,leaf structure,identity,oil space performance showed that the central was low,but the northwest and southeast was higher.The chemical quality,high content of total sugar and reducing sugar,total alkaloid,total nitrogen,chlorine content is suitable,the potassium content was generally low,the ratio of sugar to nicotine content was high,and the ratio of potassium to chlorine,the ratio of nitrogen to nicotine were in tobacco optimal range.In the sensory quality,the aroma quality was better,the aroma quantity was enough,the aftertaste was more comfortable,the miscellaneous gas was slight,the stimulation was slight,the sense of sweetness was moderate,and the concentration of the action was moderate.(2)The spatial distribution of soil factors in Liangpan tobacco growing area was analyzed by HASM_EF method,and the spatial distribution of soil nutrients was obtained About 55%of the soil organic matter content in the cold trap area was about 45%,and the soil pH value was concentrated between the most suitable range 5.5～6.5,which wasweak acid or neutral.The spatial variability of available nutrients in soil was large,and the content of soil alkali hydrolyzable nitrogen was higher on the whole.The available P was low and the total available potassium was not enough.(3)The Liangpan meteorological index in tobacco growing areas of space remote sensing and simulation based on DEM data,drawed the map and Liangpan meteorological factors spatial distribution area of 90m spatial resolution,among them,the percentage of sunshine,temperature,sunshine duration,residual precipitation,relative humidity average values were 0.87℃,0.25%,4.18 h,0.95 mm,0.33%,which was high accuracy.Space,air temperature had the North South high-low trend;the percentage of sunshine and sunshine hours decreased,higher than the Northeast southwest;the maximum rainfall area from April to August from north to South mobile.(4)Using PLR model to identify the main ecological factors of affecting the quality of tobacco and the suitable interval of major ecological factors was extracted by using ROC curve.The results showed that,The main factors of appearance quality were the precipitation in August which the suitable interval was 177.31-189.12 mm,the relative humidity in April which the suitable interval was 52.41-54.35%,and the precipitation in April which the suitable interval was 37.13-40.61 mm.The main factors of chemical quality include the precipitation in August which the suitable interval was 193.56-195.57 mm,the precipitation in May which the suitable interval was 80.10-87.91 mm,and the precipitation in July which the suitable interval was 212.81-214.24 mm.The main factors of sensory quality include the sunshine hours in September which the suitable interval was 123.67-125.57 h,the sunshine hours in May which the suitable interval was 204.38-209.90 h,the sunshine hours in April which the suitable interval was 236.05-239.33 h,the percentage of sunshine in September which the suitable interval was 35.10-36.46%,and the som was 30.29-32.41 g/kg。... |
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