The Study On Environmental Quality Of Soil And Tobacco Chemical Quality In Yunnan Zhaotong Tobacco-planting Areas

Soil environmental quality directly impacts on the production and quality of the tobacco, thereby affecting the competitiveness and economic benefits of tobacco products, In recent years, China has carried out a number of studies of soil environment quality in tobacco growing areas, the results show that there are different degrees of heavy metal pollution in tobacco-growing soils, big differences about soil fertility and mineral content in different regions. flue gas characteristics of tobacco in different regions is different, which is closely related to the soil environment. Yunnan Zhaotong had a long history in planting tobacco, wide geographical distribution of tobacco planting soil and planting areas, but the relationship between soil environmental quality and the quality of tobacco had not yet have a system of monitoring and evaluation. Therefore, this study had carried out a comprehensive monitoring which includes21indicates, such as soil fertility, content of amount elements and trace elements, mainly heavy metal content about the605soil samples which ware collected by systematic sampling, according to the Zhaotong Tobacco-planting areas distribution and cultivation of tobacco. At the same time, monitoring sites received a total of458tobacco samples (include150tobacco samples collected an the time when the soli samples are collected), heavy metals and chemical quality of a total of15indicators were monitored. according to the monitoring results, evaluate the soil quality conditions and the quality of tobacco in the study areas comprehensively, referring to the soil fertility evaluation reference index, soil environmental quality standards, tobacco chemical quality indicators grading standards and recommended indicators; at the same time,this study investigated the relevant law between tobacco health quality and soil properties, using the soil-tobacco simultaneous monitoring data as basis and multivariate statistical analysis. All above could provide a basis to how to optimize the layout of tobacco and manage the cultivation in Zhaotong. The main conclusions are as follows: 1. The monitoring results of soil in Zhaotong Tobacco-planting Areas show that the city’s soil fertility is higher than the national average level, most of the soil is suitable for the cultivation of tobacco. The suitable pH range for tobacco planting soils is5.5to7.0, according to this standard, there ware over50%of the soil in Zhaotong planting tobacco-growing areas was suitable for tobacco cultivation. In accordance with the requirements of Soil Fertility in planting tobacco, the area that the content of soil organic matter and phosphorus ware moderate above the standards ware71.8%and75.1%of the total areas, the content was rich; the area that the content of soil nitrogen and potassium ware moderate above the standards are52.7%and58.6%of the total areas, the content was rich.The content of most amount and trace elements ware abundant in Zhaotong Tobacco-planting area soils, but some separate trace elements was lack, so it brought a good protection for the production of quality tobacco. In accordance with the standard of the trace element content of tobacco soil, the content of effective zinc, the effective manganese, effective copper and exchangeable magnesium was rich in the tobacco planting soils of the city, the area that the content was moderate above the standards was85%of the total areas. The average content of exchangeable calcium and effective molybdenum in Zhaotong Tobacco-planting area soils ware slightly higher than the national level, accounted for65.8%and60%of the total areas whose content ware above the moderate level. The average content of effective boron and water-soluble chlorine in Zhaotong Tobacco-planting area soils was lower than the national level, and its content was essentially lower than the critical value of Tobacco-planting soil’s needs. Need to add the appropriate amount of boron and chlorine fertilizer.According to the secondary standard of national soil environment, the heavy metals in Zhaotong Tobacco-planting area soils was generally not exceeded, but there ware also the phenomenon of excessive individual elements. From a single pollution index, only nickel content exceed commonly in each of tobacco planting soils, the rest of the heavy metal have not reached the pollution levels, the size of over standard rate was:Ni> Cd> As> Pb, mercury content was not exceeded. According to nemerow pollution assessment, Zhaoyang was in a security level, in addition to the Qiaojia was in the the mild pollution level, the level of contamination of the remaining six counties ware in the alert level.2. To conduct monitoring and analysis of tobacco leaf in Zhaotong Tobacco-planting Areas, and follow the standards of it production of pollution-free, Overall quality of tobacco leaf was good, Single heavy metal content in tobacco leaves to exceed bid badly; The over standard rate for the heavy metals in tobacco leaves was Ni>Pb>Zn>Cu>Cd, Hg and As not to exceed bid. The over standard rate of Cu was19.91%in the tobacco leaves, mainly distributed in Weixin and Yongshan.The over standard rate of Zn was31.20%, mainly distributed in Zhaoyang、Zhenxiong、Yiliang and Ludian. The over standard rate of Ni was96.03%, as the main pollutants, generally there ware overweight in Zhaotong Tobacco-planting Areas. The over standard rate of Pb was67.04%, mainly distributed in Ludian、Qiaojia、Yiliang and Daguan. The over standard rate of Cd was4.01%, mainly distributed in Zhaoyang.Chemical elements of tobacco leaves overall reach the quality requirements of tobacco in Zhaotong Tobacco-planting Areas, With the average contents of total nitrogen, nicotine and starch are within the quality requirements of tobacco. With the average contents of total sugar and reducing sugar are exceed the quality requirements of tobacco. But with the average contents of chloride ion and potassium ion ware below the quality requirements of tobacco. Difference of reducing sugar and total sugar of tobacco leaves were more than5%in Zhaotong Tobacco-planting Areas; K/Cl of tobacco leaves was8.77; Schmuck’s value of tobacco leaves was5.98; The ratio of total nitrogen to nicotine of tobacco leaves was0.64; The ratio of total sugar to nicotine of tobacco leaves was9.98.3. The correlation analysis of tobacco leaves heavy metals and soil heavy metals, it shows Ni、Pb、Cu in the tobacco leaves ware very significantly correlated with Ni、Fb、 effective Cu in the soil, the correlation coefficients ware0.2309、0.2965and0.3022; As、Hg、Cd、Zn in the tobacco leaves ware not significantly correlated with these heavy metals in the soil. The study about related law between tobacco heavy metals and soil physical and chemical properties shows that the main factors affecting the copper in tobacco ware soil available phosphorus, the effective potassium, organic matter and total nitrogen. The main factors affecting the arsenic in tobacco ware soil available phosphorus, total phosphorus, soil acidity, available nitrogen and organic matter. The main factors affecting the Lead in tobacco ware soil effective potassium, available phosphorus, total phosphorus, total nitrogen, soil acidity and available nitrogen. The main factors affecting the cadmium in tobacco ware soil effective potassium,soil acidity,organic matter,total cadmium, total potassium, and available nitrogen. The main factors affecting the mercury in tobacco ware soil total phosphorus, organic matter, total potassium, total mercury and total nitrogen. The main factors affecting the zinc in tobacco ware soil available potassium, available nitrogen, total potassium and soil ph, total nitrogen and total phosphorus, effective phosphorus. The main factors affecting the nickel in tobacco ware soil total nickel, organic matter, effective nitrogen, available potassium, effective phosphorus and total potassium.