Relationship Between Soil Nutrient Status And Flue-cured Tobacco’s Growth And Chemical Composition In Guangyuan

Soil nutrient status are the main factors for the tobacco growth and quality formation. In this paper, the suitable assessment of tobacco planting soil was evaluated in the Guang yuan region of Sichuan province. Then, the effect of the change of soil nutrient on the tobacco agronomic traits and the main chemical components contents of fresh tobacco leaves were studied during the flue-cured tobacco growth and development process. The relationship between soil fertility and the final chemical quality of flue-cured tobacco has also been investigated. The main results showed as follows:1, The pH value of tobacco planting soils was mostly alkaline in Guangyuan, it accounted for68.51%whose value was greater than7.5. The soil nutrient content was in a wide variation, unbalanced distribution. For the tobacco planting soils, the average content of soil organic matter was16.18g/kg, of which the suitable soil samples accounted for51.35%. The average content of total nitrogen was1.05g/kg, of which the content with middle and rich accounted for52.26%. The distribution of available phosphorus in study area varied greatly, with an average content of13mg/kg. The most suitable sample accounted for41.65%. The average content of soil available nitrogen was79mg/kg, with a suitable content range accounted for88.60%. The average content of available potassium was110mg/kg, which was below the critical value of abundance and deficiency judgment. The proportion of soil available potassium deficiency was a larger of71.22%, which was difficult to meet the demand for high yield and quality tobacco production. Soil exchangeable calcium and magnesium content were higher, the average content were1810.2mg/kg and80.27mg/kg respectively. The content of available sulfur changed in the range of2.01-214.56mg/kg, with suitable samples accounted for22.69%, rich and very rich accounted for38.72%. The contents of available iron, manganese and zinc were richer, the average content of them werel6.12mg/kg,15.4mg/kg and1.24mg/kg respectively. Available copper content was in medium, the average content was1.15mg/kg, of which above a critical value accounted for45.48%.The soil available boron was in rather deficit with an average of0.31mg/kg, of which deficiency and larger deficiency accounted for90.18%, which arear need to replenish the boron fertilizer. Chloride ion content was richer in soil, with the average content of0.04g/kg. The proportion of chloride ion content, which was suitable and quite suitabler accounted for79.91%. It meets the demand of chlorine for tobacco planting.According to soil nutrient suitability index and the membership, the fifteen analysis indexes of tobacco planting soil nutrient were evaluated for suitability assessment in different villages and towns. It was found that the subordinate degree of pH and water soluble chloride ion were fluctuat in the samples. For other nutrients, there are some room to improve except available manganese and alkali solution nitrogen in the regional soil. The comprehensive fertility of soil samples mainly was medium and high, which was more suitable for tobacco growing. The soil comprehensive score of Wangcang was higher in three counties of Guangyuan. The soil samples pertain to Grade I was accounting for12.5%, Grade Ⅱ was87.5%, that was suitable for tobacco planting. There were respectively63.64%and63.16%villages and towns in Jiange and Yuanba for suitable to planting tobacco.2, The method, gray correlation degree was adopted to analyze the relationship between soil nutrient factors and the tobacco plant growth status of Yunyan87.The results show that:The soil nutrient factors and the growth of tobacco plants was in different influence. As in the Muma site, the condition of tobacco plant growth was closely associated with effective Mo, S and available P. In Yaojia and Chengbei, the soil nutrient factors were available K and soil pH. While in the Jianmenguan, available Cu and P deeply affect the growth of tobacco plants. The soil available S and Mo were closely related to the growth of tobacco plant in Liugou. Available Zn and soil pH may became the restrictive factors of tobacco plant growth in Puan. Targeted adjustment should to do in each district for improving soil fertility according to the local nutrient index status.3, During the field process, the chemical components of fresh tobacco leaves were the basics of tobacco quality, of which formation and accumulation was a dynamic process effected by soil nutrient always. The results of grey correlation degree analysis between sites soil nutrient change and the chemical components of fresh tobacco leaves Yunyan87showed that:the important soil factors effected the total sugar and reducing sugar content of fresh tobacco leaves were soil alkaline hydrolysis nitrogen and Fe in Jianmenguan; They were soil pH, exchangeable Ca and water soluble Cl in Liugou; They were available K, organic matter, available S and P in Chengbei; They were alkaline hydrolysis nitrogen and water soluble Cl in Yaojia; They were total nitrogen, available Fe and Cu in Puan. The main factors that influenced the total nitrogen conten of tobacco fresh leaves were trace elements in addition to nitrogen. P were the restrictive factor of total nitrogen accumulation, because phosphorus will promote tobacco plants absorb more nitrogen. The trace elements were the important soil nutrient factor effecting the tobacco nicotinic of fresh leaves. Tobacco potassium content and accumulation were related to soil water soluble chloride, available K, P, alkali solution nitrogen, effective Mn and exchangeable Ca.4, The relationship between soil nutrient and chemical components of flue-cured tobacco leaves was studied through the stepwise regression equation establishment. The results shown that:The impact of the soil’s trace elements to the changes of tobacco chemical components was apparent, because the large elements basically got sufficient supply in the local existing fertilizer technology. The establishing stepwise regression equation between volatile aroma components and soil nutrient factors revealed that:the linear relationship between carotenoids, cembrane type, neophytadiene and other volatile substances of cured tobacco leaves and part of soil fertility change are significant and extremely significant. Wherein, the carotenoid with soil available B was significant negative correlation, while with soil water soluble chloride ion was significant positive correlation. The cembrane type with soil available Cu was a very significant negative correlation and the soil alkali solution nitrogen showed an extremely significant positive correlation; The Nephytadiene contents with soil available B was a extremely significant negative correlation, with soil available Cu was significant negative correlation, while with exchangeable Ca and Mg were extremely significant positive correlation. Other volatile substances and soil water soluble chloride ion content was a significant negative correlation, while it was an extremely significant positive correlation related to the soil available Fe, Mo and exchangeable Ca,Based on the above research results, Guangyuan in improving tobacco nutrition should be properly adjusted in tobacco planting soil pH value, strengthen pair of trace element content in soil of control factors on tobacco planting regions; combined with the local actual situation, makes the soil exchangeable calcium, magnesium, zinc, iron, water soluble chloride ion, manganese and effective alkali hydrolyzable nitrogen control or maintain in proper condition; part of tobacco-planting areas appropriate to add soil organic matter, total nitrogen, available phosphorus and available sulfur; on the whole by increasing and improving potassium fertilizer, boron fertilizer application rate and utilization rate of tobacco production in the region and the last step.