Distribution Characteristics Of Soil Available Molybdenum Content And Its Relationship With Tobacco Leaf Quality In Middle Altitude Tobacco Fields In Qujing

Combining fieldwork and experiment analysis together,we collect 1605 soil samples in medium-level tobacco planting soil covering nine counties or cities of Qujing tobacco-growing area,and conduct analysis and determination on their effective molybdenum content and that in their corresponding tobacco,in order to give a research to such content’s overall situation and variation features.Taking tobacco-growing area located at medium-level red soil of Qujing as example.After carrying out an analysis of 280 soil samples and their corresponding tobacco molybdenum content,nutrient element content,as well as the relationship between their major chemical component and sensory quality,we arrive at the following conclusion:1.We have obtained 1605 soil samples and corresponding tobacco samples in Qujing’s medium-level tobacco planting soil,and come to such conclusion after analyzing the covering of its effective molybdenum content and tobacco molybdenum content:(1)With average molybdenum content of 0.199 mg/kg,its overall distribution is appropriate,while it is vulnerable to variation,and deficient samples takes up a high proportion.A notable gap exits in different regions.Luoping County and Shizong County enjoy high effective molybdenum content of 0.32 mg/kg and 0.31 mg/kg respectively,while Qilin,Zhanyi and Luliang County,as opposed to the former,just have 0.11 mg/kg,0.11 mg/kg and 0.13 mg/kg respectively.The effective molybdenum content in other counties and cities’ soil ranges from 0.15 mg/kg to 0.20 mg/kg.(2)Average molybdenum content in Qujing’s medium-level tobacco-growing area is 0.227 mg/kg,amplitude of variation being 2.687 mg/kg with high variable coefficient of 71.45%.Shizong County,having the notably highest molybdenum content,boasts of average 0.377 mg/kg,and the obviously lowest,Malong County,just has average 0.088 mg/kg.2.We have obtained 1605 soil samples in Qujing’s medium-level tobacco planting area to research its variation of effective molybdenum:(1)red soil,paddy soil and purple soil are major parts,of which red soil takes up the largest of 63.80% of all samples;the next,paddy soil,28.41%;and purple soil,the lowest,7.79%.Correspondingly,with averagely 0.21 mg/kg,effective molybdenum content in red soil is the highest,then,the paddy soil,and purple soil,the last.Variable coefficient of effective molybdenum content in the three soils are all high,dispersion degree being large in all of the three.Among the three soils,samples with deficient effective molybdenum content takes up to 54.39% in paddy soil,47.95% in red soil,and 57.60% in purple soil,while those with appropriate effective molybdenum content takes up 13.16%,15.63% and 20.00% respectively as the above sequence.So in general,the average of that in the three soils is larger than 0.15 mg/kg.However,samples with less than 0.15 mg/kg effective molybdenum content occupies a large proportion.(2)after analyzing the p H content and effective molybdenum content of such soil samples,we conclude that the average p H content is 6.31,in keeping with that of quality flue-cured tobacco soil.While after analyzing the p H content and effective molybdenum content of different soils in this region,we conclude that the effective molybdenum content in red soil has significantly positive correlation with its p H content,that in purple soil,significantly negative,while that in paddy soil has nothing to do with its p H content.(3)after analyzing different oxide content and effective molybdenum content,we conclude that the soil’s oxide resulting from ferrum and calcium has significantly negative correlation with its effective molybdenum content,while its manganese content,significantly positive.3.Taking tobacco located at Qujing’s medium-level red soil as example.We divide samples’ effective molybdenum content into five groups: that less than 0.1 mg/kg,ranging from 0.1 mg/kg to 0.15 mg/kg,from 0.15 mg/kg to 0.20 mg/kg,from 0.20 mg/kg to 0.30 mg/kg,and more than 0.30 mg/kg,so as to research the relationship between effective molybdenum and corresponding tobacco’s molybdenum content of sampling soils.We find that where the effective molybdenum content in soil grows,the tobacco’s molybdenum content grows,while in case that such content in soil is more than 0.30 mg/kg,the corresponding growing in tobacco go slow notably,too.The molybdenum content of soil in this group varies majorly compared with the others,while its content in tobacco is similar with that in group with such content ranging from 0.20 mg/kg to 0.30 mg/kg.4.Taking tobacco located at Qujing’s medium-level red soil as example.After analyzing 280 tobacco samples in this region and their chemical component we find that:(1)the overall sugar content in its regular chemical component is comparatively high,the nitrogen content,comparatively low,and the content of reducing sugar,nicotine as well as starch is perfect.Correlative tests shows that the content of overall sugar,nitrogen,nicotine as well as starch has the most significantly positive correlation with molybdenum content in tobacco,while content of reducing sugar,significantly positive.(2)among nutrient elements in this region’s tobacco,molybdenum content in tobacco has negative correlation with content of potassium,calcium,sulfur,copper,zinc,ferrum,manganese and boron in tobacco,of which potassium,sulphur,ferrum,manganese and boron is notable,while with the content of chlorine,magnesium and phosphorus,molybdenum content in tobacco show positive reaction,of which magnesium and phosphorus notable.5.Taking tobacco located at Qujing’s medium-level red soil as example.We divide 280 tobacco samples into groups(that less than 0.1 mg/kg,ranging from 0.1 mg/kg to 0.30 mg/kg,and more than 0.30 mg/kg)making molybdenum content in tobacco as standard.After analyzing the content and sensory quality we conclude that:(1)the quality of fragrance lies in medium level,rich but a little offensive,aftertaste being proper.With upper-or medium-level combustibility,its ash appears gray,scoring high.Its concentration and energy is proper,medium-level fragrance.Its trend to be masses is proper,a little dry,moderately sweet,and proper soft.(2)when molybdenum content is more than 0.30 mg/kg,the quality,quantity,offensive smelling,color of ash,concentration and energy scores high.When it is ranging from 0.1 mg/kg to 0.30 mg/kg,the aftertaste,combustibility,style of fragrance,and trend to be masses scores high.When it is less than 0.1 mg/kg,the offensive smelling,sense of drying,sweetness and softness scores high.(3)with the increasing of molybdenum content in tobacco,scores of quality,quantity,aftertaste,color of ash,concentration and energy scores higher firstly then go downwards with notable regression.With the increasing of molybdenum content in tobacco,offensive smelling scores lower firstly then go upwards with notable regression.While combustibility,style of fragrance,trend to be masses and sense of drying show insignificantly regression with molybdenum content in tobacco.