Research On Characters Of Heavy Metals In Flue-cured Tobacco Using Artificial Neural Network

The characters of heavy metal contents and accumulations in the flue-cured tobacco were investigated and obtained related data of heavy metals in tobacco plants and soils, soil and weather factors that affect them using the same cultivation model in 11 counties of 7 provinces lasting for 3 years. At the same time, the artificial network we used to study the layout of tobacco planting zones, the ecology factors that affect the contents and accumulations of heavy metals in flue-cured tobacco, the importance of ecology factors in quantity evaluation of tobacco. The mathematic and neural network models were built up according to the relationship between the accumulation characters of the heavy metals and the surrounding factors, and then to use these models to forecast the contents of heavy metals in flue-cured tobacco.1 The contents and accumulation of the heavy metals in the flue-cured tobacco plantThe content of Cu in the flue-cured tobacco plant was shoots> flowers> roots> stems> leaves in turn; Zn was shoots and flowers> roots and stems and leaves in turn, and that in the roots was almost equal to that in the leaves; Mn was leaves> roots> flowers> shoots> stems; Pb was roots> leaves> shoots> stems> flowers; the content of Cd in the leaf was much higher than that in the other organs. In general, Cu and Zn had higher content in the flowers and shoots, Mn and Cd were concentrated in the leaves mainly, and Pb was located in roots.The degree of dispersion in different parts of tobacco plant showed that the standard deviation of the Cu and Cd were consistent by and large in all organs, meanwhile the standard deviation of the Zn, Mn and Pb in the roots and leaves were greater than that of the other organs. Asymmetry coefficient of Cu in the leaves and roots, Zn in the shoots and roots, Mn, Pb and Cd in all parts of the plant showed positive. The values of kurtosis coefficient larger than 3 included Zn in the roots and shoots, Mn in stems, Pb in the leaves, stems and shoots, and Cd in the stems, leaves and shoots. The values...