Effect Of Nutrition Regulator And Nano-Silicon On The Content Of Heavy Metals And Potassium In Flue-cured Tobacco Leaves

To explore the effects and the mechanisms of Nano-Silicon(N-Si) and Nutrition Regulator (NR) on the contents of potassium and heavy metals (Pb、Cd) in flue-cured tobacco leaves, a field experiment was conducted. It was designed as the combined application of N-Si and NR with the duality-quadratic saturation D-optimization design. The growth and yield of flue-cured tobacco, the contents of potassium and heavy metals (Pb、Cd) in flue-cured tobacco leaves were studied. Through potted test and simulation test, determination soil pH, exchangeable potassium, available calcium,available magnesium, heavy metal speciation and the heavy metal effective State, Explore the mechanism of NR and N-Si increased the content of potassium and reduced the content of heavy metal in flue-cured tobacco.The conclusions are described as follows:1. The yield of flue-cured tobacco was increased significantly by means of combined application N-Si and NR, improved the agronomic characters and tobacco growth. Among all treatments, the increment of yield was most in the T5(NR46.02kg/ha N-Si45.00kg/ha). It was8.8%higher than the Treatment2(N-Si45.00kg/ha) and6.7%higher than the Treatment3(NR66.00kg/ha).2. The potassium contents in flue-cured tobacco leaves were increased significantly by means of combined application N-Si and NR. Among all treatments, the increment of potassium contents in upper, middle and lower leaves were most in the Treatment5,it contained3.1%,3.6%and2.7%.Compared with upper, middle and lower leaves, they were61.4%,42.1%and56.6%%higher than the CK. Upper and middle leaves achieved the International high quality tobacco potassium content standards of3%.3. The contents of heavy metals (Pb、Cd) in flue-cured tobacco leaves were descended significantly by means of combined application N-Si and NR. Among all treatments,the contents of Pb and Cd in tobacco was the lowest with Treatment5. Compared with CK, the Pb contents of upper, middle, lower leaves have fallen by53.4%,30.2%and39.4%respectively, and Cd contents of upper, middle, lower leaves have down by46.8%,49.7%,54.6%respectively.4. The contents of heavy metals Pb and Cd in the soil had been passivated after application the N-Si and NR. It can significantly reduce soil DTPA extracting contents of available Pb and Cd, which reduced the bioavailability of heavy metals Pb and Cd in soils. Treatment5reduced most significantly, compared with CK, the content of available Pb have fallen by32.0%, available Cd have down by90.4%. NR effected of Pb and Cd in soil by acid extractable and reversible state reduced, oxidation state and rump state increased, N-Si effected of Pb and Cd in soil by acid-extractable residues modal transformation, its best for application N-Si and NR.5. The contents of exchangeable Ca, Mg in soil was reduced significantly by means of combined NR and N-Si,the content of available K in soil was improved.The ratio of K/(Ca+Mg) was improved, more conducive to the absorption of potassium in flue-cured tobacco. Among all treatments, the decrement of exchangeable Ca, Mg was most in the fifth treatment,the addition of available K was most in the fifth treatment.Treatment5compared with CK, the content of exchangeable Ca in soil decreased by35.7%, the content of exchangeable Mg decreased by39.4%, the content of available K improved by85.2%.