| Field experiments were conducted in Dunhua county of Yanbian region of Jilin Province in 2008, selectling three representative and larger planting area soil types: dark brown soil, black sand soil ,and white slurry soil as the research object, tested tobacco varieties was for JiYan 9, after transplanting tobacco 20d, 40d, 60d, 80d, 100d, 120d six reproductive period, collected rhizosphere, non-rhizosphere soil, and the tobacco samples, studied the dynamic changes of microorganisms in rhizosphere and non-rhizosphere, the dynamics changes of soil enzyme activity and nutrient and chemical constituents in flue-cured tobacco leavies and their analysis of the correlation. The objective is to identify the possible biological factors to further improve soil fertility and improve the quality of tobacco leaves at this stage , aimed at high-quality tobacco leaf production and ecosystems to provide sustainable and stable development of reference. The main conclusions are as follows:1. The three soil types, the number of micro-organisms in flue-cured tobacco rhizosphere and non-rhizosphere have shown the same law: bacteria> actinomycetes> fungi, which is generally similar to farmland soil microbial composition. In addition, the amount of microorganisms is different from different soil types, and the test showed that the amonut of rhizosphere bacteria and Actinomyce has with the following results: dark brown soil>black sand soil>white slurry soil, non-rhizosphere bacteria in the three soil types showed the same laws as above, but the amount of fungi is without any obvious changes in the law. The amount of rhizosphere micro-organisms was changed in different stages of flue-cured tobacco growth process. It is showed that the bacteria was least in the period of 20-40d after transplanting, then increased gradually, and the peak value appeared at the date of 60d after transplanting,after then, the bacteria began to reduce; but the amount of actinomycetes and fungi was showed to have the trend to increase gradually. In different growth stages, the bacteria, actinomycetes and fungi in the three soil types have shown the same law with significant rhizosphere effect as following: the rhizosphere> non-rhizosphere, (R / S).2. Ammonification bacteria, Nitrosococcus bacteria, nitrifying bacteria, nitrogen- fixing bacteria self, solution of potassium aerobic bacteria and cellulose-degrading bacteria in the three Rhizosphere soil types are changing in different growth process. It is showed that the beneficial microorganisms in the rhizosphere of dark brown soil is better than black sand and white slurry soil..3. The peak value of converting enzyme, polyphenol oxidase, catalase and urease, which content in dark brown soil, black slurry soil and white slurry soil, appeared in the period 40d-60d after transplanting, and it was also the tobacco plant vigorous growth stage till squaring stage, since there is a large number of nutrients and an adequate supply of nutrients, the temperature and moisture during this period are also suitable for the growth of micro-organisms, thus the enzyme have higher activity. synthetical adjustment, the four enzyme activities in dark brown soil are slightly higher than that in the other two types soil.4. In tobacco reproductive period, the non-rhizosphere pH values of three types soil are all higher than that of root, named: pH(non-rhizosphere)> pH(root), this result may be associated with root exudates of tobacco-relationship; this result went all throught the entire growth stages, only with small fluctuation; the pH values of rhizosphere and non-rhizosphere in different soil types are as flowing: dark brown soil>black sand> white slurry soil.5. Rhizosphere soil nitrogen fertility of the three types soil showed a downward trend during all the tobacco growth stages; and for rhizosphere soil, the nitrogen changes in the soil types is with the following trend: white slurry soil>black sand>dark Brown; During the entire reproductive, available P changes in the rhizosphere of tobacco in the three types of soil performance are different: In the 120d, the percentage of rhizosphere phosphorus P in the dark brown soil is slightly higher than that of the black slurry soil and white slurry soil; the changes of rhizosphere oil K in the soil types is as following: dark brown soil> black sand> white slurry soil. In the 120d, the percentage of available K in rhizosphere soil in the dark brown soil is higher than that of black slurry oil and white slurry oil.6. During the entier growth process, the changes for water-soluble sugar and reducing sugar in the different soil types are all with the same trend; the percentage of nicotine is with upward trend; meanwhile the percantage of thetotal nitrogen is with downward trend ; the dynamic changes of potassium percentage is also with the same trend, showing an upward at the beginning and then downward trend in laws till harvest, the percentage of potassium in the three types soil are with the following results: dark brown soil> black sand> white slurry soil, indicating the accumulation of potassium in leaves is different from types soil; during the reproductive stage, the Chlorine percentage changes is different in different types soil, test results showing white slurry soil>black sand>dark Brown.7. From the correlation analysis, we can find that the soil microbial activity and soil have a good correlation; Enzyme and the aerobic nitrogen-fixing bacteria of Self-significant is positive correlation, but is significantly negatively correlated with the fungus; Catalase and aerobic nitrogen-fixing bacteria of Self-significant is positive correlation, but is significant negative correlation with actinomycosis; Oxidase with a number of aerobic nitrogen-fixing bacteria of Self-significant is positive correlation, but is significantly negatively correlated with the fungus; Bacterial urease is significant positive correlation with the bacteria, and also is a significant positive correlation with ammonia bacteria.8. The pH value of the soil is significant positive correlation with bacteria, bacteria Nitrosation with the solution of potassium bacteria; nitrogen and actinomycetes was significantly negatively correlated with the fungi, and aerobic cellulose-degrading bacteria is significant negative correlation digestion of bacteria and a significant positive correlation; available P and sub-nitrifying bacteria and denitrifying bacteria was significantly positively correlated with a significant negative correlation fungi; K and sub-nitrifying bacteria and denitrifying bacteria was significantly positively correlated with the solution of potassium significantly correlated bacteria.9. Tobacco leaf total soluble sugar and fungi is significantly positively correlated with aerobic cellulose-degrading bacteria significantly correlated with the nitrifying bacteria is negatively correlated; reducing sugar with the fungi and aerobic cellulose-degrading bacteria significantly correlated; nicotine with the fungi and actinomycetes significant positive correlation; total nitrogen and fungi and actinomycetes are significantly negatively correlated with aerobic cellulose-degrading bacteria is negatively correlated; potassium content with the fungi significantly negatively correlated with actinomycosis significant negative associated with the solution of potassium significantly correlated bacteria; chlorine with these types of correlation between micro-organisms did not reach significant level. To sum up, through the effects of three types of soil rhizosphere bacteria, fungi, actinomycetes and some quantity of activity, which can increase the impact of a number of N, P, K utilization efficiency of the number of beneficial microorganisms and changes in trends, improve soil fertility conditions, such as to increase the potassium in the distribution of the ratio of leaf to leaf chemical composition in a more coordinated, so as to improve the appearance of the upper part of leaf quality and internal quality for the sustainable development of tobacco as a way to provide. |
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