Abstract: A comparative research on the impact of organic meliorants on the uptake of heavy metals and quality of Oriental tobacco Krumovgrad 90 has been carried out. Experiments have been implemented in controlled conditions. The soil used in this experiment was sampled from the vicinity of the Lead-Zinc Complex near the town of Kardzali, Bulgaria (Ostovitsa village). The pot experiment was a randomized complete block design containing ten treatments and three replications (30 pots). The treatments consisted of a control (no organic meliorants) and compost, vermicompost and peat meliorants (added at 20 t/daa, 30 t/daa 40 t/daa, recalculated based on dry soil weight). Heavy metals were measured in roots, stems and leaves of Oriental tobacco Krumovgrad 90. Applicationof organic meliorants does not lead to effective immobilization of Pb, Zn and Cd phytoaccessible forms in soil. The effect of the meliorants used for the reduction of the heavy metal content in tobacco is negligible. The best results are obtained with the introduction of 40 t/daa of compost. Organic meliorants influence tobacco quality indicators (ash, protein and reducing sugars). The introduction of organic meliorants leads to increased minerals (pure ash) and protein levels, and reduces the amount of reducing sugars in tobacco leaves compared to the control. Adding compost and peat to soils leads to improved tobacco quality. However, the introduction of 30 t/daa and 40 t/daa of vermicompost into the soil results in lower quality tobacco (Schmuck number below 0.5).
Keywords: heavy metals, organic meliorants, oriental tobacco, quality