Effect Of Fertilizer Application On Soil Heavy Mental Phytoremediation By Different Varieties Of Tobacco

This study adopts pot experiment to explore distribution of cadmium on each part of four tobaccos including Yun87, Yun97, K326, NC71, NC297 and Xiang3 that is commonly seen in Hunan Province. It analyzes these six tobaccos’cadmium absorption characteristic differences.Different fertilizers and different ratios are used in the tobacco field which has been lightly polluted by Cd to research the influence which different kinds of fertilizers and different ratios have upon the absorption of the heavy metal of tobaccos.What’s more, the influence that different kinds of fertilizers and different ratios have upon the soil PH and chemical forms of Cd in soil is also studied. The conclusion is as follow.(1) Six tobacco varieties planted in three tobacco fields and Greenhouse pots shows that, there are several differences among the heavy metal content of the tobaccos in different tobacco fields, different parts of tobacco have different abilities to concentrate heavy metal. Cd is the main element of the tobacco, and these six tobacco varieties have strong concentration abilities to Cd. The different tobacco varieties have different abilities to accumulate heavy metal and the different parts of tobaccos have obvious difference to the concentration abilities of Cd. K326 has the strongest concentration abilities of the heavy metal,while Yun87 is on the contrary.(2) The result of field experiment and pot experiment shows that using K2SO4 as topdressing fertilizer to the tobaccos, the Cd of them has a high content, while using different processed fertilizers, the content of Cd obviously decreases. Especially the pot experiment show that the effect of reducing Cd of tobaccos can be as high as twenty to fifty percent after fertilizing the different processed fertilizers,so do the renewed tobaccos. It can be seen that it is an effective way to utilize fertilizers to reduce the content of Cd in tobaccos.(3) The result of different processed fertilizers show that, the one which was fertilized by K2SO4 has few changes in soil PH and available Cd contents in soil; Comparing six different processed fertilizers of Yun87, the soil PH separately has separately increased by 0.52,0.44,0.53,0.65,0.70 and 0.57, the available Cd contents in soil has separately reduced by 23.74%,21.46%,11.87%,19.63%,26.48% and 18.26%;Comparing six different processed fertilizers of K326, the soil PH has separately increased by 0.60,0.39,0.53,0.55,0.63 and 0.58,and available Cd contents in soil has separately reduced by 25.75% ,28.76%,14.59%, 26.61% ,28.76% and 26.18%.Through the research, it can be found that different fertilizers have big differences on the chemical forms of Cd in soil, ultimately, affect the absorption of Cd.