Agriculture and Horticulture

Biography

Biography: Baljit Singh

Abstract

Heavy metal contamination of soil and water through disposal of industrial wastes poses serious hazards to human beings and the ecosystem. Trees have the ability to accumulate such toxic metals in biologically less hazardous forms. Therefore, the present investigation was conducted to determine the potential of different multipurpose tree species to tolerate and extract cadmium (Cd) and lead (Pb) from the soils contaminated with these heavy metals. Phytoextraction potential of four multipurpose tree species viz. eucalyptus (Eucalyptus tereticornis), subabul (Leucaena leucocephala), dhrek (Melia azedarach) and shisham (Dalbergia sissoo) was determined at six rates each of applied Cd (0, 10, 20, 40, 80 and 120 mg/kg soil) and Pb (0, 30, 60, 120, 180 and 240 mg/kg soil). Dry matter (DM) of leaves, stems and roots, Cd and Pb content of these components and that of soil were determined after 18 months of plant growth in the earthen pots filled with 8 kg soil/pot. Subabul had the highest (312 g/pot) and eucalyptus the lowest (195 g/pot) total DM without application of these metals. Highest level of Cd resulted in 49, 41, 26 and 43% and that of Pb 39, 35, 23 and 24% reduction in DM of eucalyptus, subabul, dhrek and shisham, respectively over control. Subabul had the highest average uptake of Cd (40.8 mg/pot) and Pb (59.8 mg/pot). The AB-DTPA (ammonium bicarbonate – diethylene triamine penta acetic acid) extractable Cd and Pb in the soil after harvesting of the plants were the lowest in subabul and the highest in shisham pots. The critical levels of Cd and Pb in the soil were the highest for dhrek and the lowest for eucalyptus. Among these tree species, subabul can be rated as the best tree species for phytoextraction of Cd and Pb from the polluted soils. Further studies are required to evaluate the potential of fast growing tree species to extract heavy metals from contaminated soils under field conditions.