Study on the Effect of Potassium Fertilizer and the Nutrition Regulator on the Contents of Potassium and the Heavy Metals in Flue-cured Tobacco Leaves

To explore the effect of potassium fertilizer and the nutrition regulator(NR) on the yield of flue-cured tobacco and the contents of potassium and heavy metals(Cu,Zn,Cd and Pb) in flue-cured tobacco leaves,a field experiment was conducted.It was designed as the combined application of potassium fertilizer and NR with the duality-quadratic saturation D-optimization design.A primary evaluation was made about the potential harm of the heavy metals(Cd and Pb) in the flue-cured tobacco leaves to human bodies.The results showed that the combined application of potassium fertilizer and NR could increase the flue-cured tobacco yield significantly and enhance the potassium content in the flue-cured tobacco leaves.It had the best effect in the 5th treatment,the yield was 29.03% higher than the 1st treatment,the potassium contents in upper,middle and lower leaves were 109.09%,115.54% and 86.29%.At the same time,the combined application of potassium fertilizer and NR could decrease the heavy metals(Cu,Zn,Cd and Pb) content in flue-cured tobacco leaf significantly.It had the best effect in the 6th treatment,the content of Cu,Zn,Cd and Pb were 27.30%,9.74%,34.46% and 39.01% lower than the 1st treatment,respectively.The evaluation result showed that the quantity that a person exposes to heavy metals(Cd and Pb) in the flue-cured leaves per day under all treatments was lower than the ADI value that stipulated by the FAO/WHO.In the treatments which applied the NR the quantity were lower.So,the NR could reduce the potential harm of the heavy metal in flue-cured tobacco to human bodies.