Effects Of Mg,B,Zn Nutrition On Growth And Physical-chemical Index Of Flue-cured Tobacco

The study focused on the evaluation on nutrient status of tobacco-growing soil in Tengchong by taking samples through large areas, and pointed out the basic fertility characteristics of tobacco-growing soil in this area and finded out the main constraint factors which influence on tobacco production.The study also analysed fertilizers such as Magnesium.Boron and Zinc's application effect on tobacco-growing soil in Tengchong by the way of pot experiment.The main research results were as follows:(1) The results of the study on the evaluation on nutrient status of tobacco-growing soil in Tengchong showed that tobacco-growing soil in most part of Tengchong tobacco-growing areas tended to be acidification, of which the acidification of texture sand such as sand, sandy loam and loam soil were especially serious.It also showed that the content of soil organic matter and available nitrogen in the soil tended to be high, of which loam and clay loam were most obvious. And the content of soil available phosphate in the soil was also much high,of which sandy soil was redundancy.But the content of soil available kalium in the soil was relatively low,of which all kinds of texture soil except for loam severely lack of kalium.In addition that, the content of exchangeable magnesium in the soil is extremely low,of which all kinds of texture soils seriously lack of magnesium. However, the content of available zinc in the soil was comparatively rich.The content of available boron tended to be low, and the water-solute chloridion content was suitable.On the whole,the differences of the content of trace elements among different texture tobacco-growing soils in Tengchong was not great. Analysing in terms of the application of soil,the acidity of dry field soil was more serious than that of paddy field soil.Except for Phosphorous, Magnesium, the content of the other nutrition elements of dry field soil was higher than that of paddy field soil.(2) The results of the study on the effect of fertility of tobacco-growing soil applied different MgSO4 in Tengchong showed that when the amount of application of MgSO4 was 4-8g/p, it could effectively promote the growth and nutrients absorption of tobacco plants. And it turned to be the trend that with the increase of the amount of application of Magnesium fertilizer, the effect of fertility would be increased.And the effect under the amount of application of 8g/p MgSO4 was best. When the amount of application of MgS04 was 16g/p, it would impede the growth of tobacco plants.(3) The results of the study on diffences of the effect of fertility applied different Magnesium fertilizer between paddy field soil and dry field soil in Tengchong showed that the effect on promoting the content of exchangeable Magnesium of tobacco-growing soil applied MgSO4 was best,but it would also further acidize the tobacco-growing soil.And the soil enzyme activity was significantly lower than that applied dolomite powder and FCMP fertilizers.By applying dolomite powder and FCMP fetilizers,it could not only increase the content of exchangeable Magnesium,but also improve or remain PH value of tobacco-growing soil.The effect of applying dolomite powder fertilizer was better than that of applying FCMP fertilizer.The soil applied dolomite powder fertilizer contained more soil enzyme activity and exchangeable Magnesium,which showed that by applying dolomite powder fertilizer in tobacco-growing area in Tengchong could create a better environment for tobacco plant and could provide much more Magnesium.Results also showed that the status of deficiency of magnesium of dry field soil was more serious than that of paddy field soil in Tengchong.By applying each kind of magnesium fertilizer could effectively alleviate the symptoms of magnesium deficiency of tobacco plants.The tobacco growing situation of dry field soil applied dolomite powder was best,then applied MgSO4 fertilizer.The effect of applying FCMP fertilizer was not as good as other magnesium fertilizer. While the effect of paddy field soil applied FCMP fertilizer was best, and then applied dolomite powder fertilizer. Applying MgSO4 fertilizer in paddy field would make a negative impact on the growth of tobacco plant.(4)The results of the study on the influence of tobacco-growing soil applied boron fertilizer in Tengchong on the growth and nutrition absorption of flue-cured tobacco showed that when the amount of application of borax was 0.8-1.6g/p, it could effectively promote the growth of tobacco plant and could shorten the growth circle.And when the amount was 0.8g/p,the effect was the best.With the improvement of the level of application of borax,the facilitation on the growth of tobacco plant would get down,then the cotent of boron in each part of tobacco plant would be gradually increasing. When the amount of application went up to 3.2g/p,it would go against the growth of tobacco plant.(5) The results of the study on the influence of tobacco-growing soil applied zinc fertilizer in Tengchong on the growth and nutrition absorption of flue-cured tobacco showed that the facilitation of the application of zinc to the growth of tobacco plant was comparatively low.When the amout of application was lg/p,it could promote the growth and nutrition absorption of tobacco plant to some extent,but the improving degree was relatively limited.When the amout was 2-3g/p,it would impede the growth and nutrition absorption of tobacco plant to different extent.which would be short and small,with a poor stress resistance.