HEAVY METAL CONCENTRATIONS IN SOIL AND TOBACCO PLANTS FOLLOWING LONG-TERM PHOSPHORUS FERTILIZATION

R. Bozhinova

Abstract: The effects of the different phosphorus rates (0; 75 and 225 kg ha-1) on heavy metal concentrations in soil and tobacco plants have been studied in a stationary field trial. A long-term fertilizer experiment with continuous tobacco cropping system was established on rendzina soil (Rendzic Leptosols) in 1966. Although P fertilizers are considered a source of anthropogenic contamination of soil, the application of increasing P rates did not increase the total Cd, Pb and Cu content in the soil. Slightly higher Ni concentration was observed in plots receiving supplemental P fertilizer as compared to 0 kg P2O5 ha-1 treatment. The changes in the available Cd and Pb content as a result from the long-term P fertilization are insignificant. There was significant increase of available Ni and Cu in the plots treated with 225 kg P2O5 ha-1 compared to the 0 kg P2O5 ha-1 treatment. Increasing levels of P fertilization had no pronounced effect on Cd, Pb and Ni concentrations in leaves. Copper content in leaves decreased with the increase of P fertilizing levels. Therefore, the impact of phosphate fertilizer application on Cd, Pb, Ni and
Cu content in soils and tobacco plants was proved to be limited. Under our experimental conditions, the risk of heavy metals’ accumulation in soil and tobacco associated with long-term P fertilization was low.

Keywords: cadmium; copper; lead; nickel; phosphorus fertilization; tobacco

Date published: 2017-08-16