This study was carried out to investigate the effect of slurry composting and biofiltration (SCB) liquid fertilizer amendment on the growth, photosynthetic rate, stomatal conductance, transpiration rate, heavy metal uptake and pigment concentration of Populus alba × glandulosa grown on Cd- and Pb-contaminated soil. Plants were grown under four test conditions: control, Cd-Pb treatment, SCB fertilization and combination of Cd-Pb treatment and SCB liquid fertilization. SCB fertilization enhanced the above-ground dry matter of P. alba × glandulosa grown in Cd-Pb treated soil. On the other hand, physiological parameters such as photosynthetic rate, stomatal conductance and transpiration rate of Cd- and Pb-treated seedlings showed lower values than those seedlings grown under controlled condition. Higher contents of photosynthetic pigment were observed in the leaves of SCB-treated seedlings and the positive effect of SCB fertilization on Cd uptake implying phytoextraction potential of Cd, but not with Pb which was considered less mobile in soil. In conclusion, the application of SCB liquid fertilizer significantly affected the mobility and bioavailability of metals in soil as reflected in the altered Cd and Pb uptake, which in turn affected the phytoextraction potential of P. alba × glandulosa grown in Cd-Pb treated soil.

Key words: Populus alba × glandulosa, photosynthetic rate, photosynthetic pigment, dry weight, phytoextraction, bioavailability, Cd-Pb treated soil, slurry composting, biofiltration