Phytoremediation potential of poplar nursery for heavy metals under sewage sludge and chemical fertilizer application

A field study was conducted to evaluate the effect of sewage sludge (SS) combined with chemical fertilizers on growth and heavy metal uptake in poplar nursery. Sixteen treatments were given to poplar nursery i.e., sole application of sewage sludge and chemical fertilizers and their combinations at various doses. Maximum dry shoot weight was under 100% RDF + 10 t/ha SS (19.06 t/ha) which was at par with 75% RDF + 10 t/ha SS (17.56 t/ha). Root dry weight was highest at 100% RDF + 10 t/ha SS (3.33 t/ha) that was statistically similar to 50% RDF + 15 t/ha SS (3.30 t/ha) and 75% RDF + 10 t/ha SS (3.25 t/ha). Maximum litterfall (1.205 t/ha) was observed at 50% RDF + 15 t/ha SS which was at par with 75% RDF + 10 t/ha SS (1.142 t/ha). Sewage sludge increased Cd, Co, Cr, and Pb concentration and uptake over control without causing toxicity. Maximum soil metal build-up under 100% RDF + 15 t/ha SS was 0.341, 0.098, 0.117, and 0.288 mg kg−1 for Cd, Co, Cr, and Pb, respectively which remained below toxic limits. Contamination indices indicated enhanced bioaccumulation and translocation, particularly of Cd and Pb, demonstrating poplar’s phytoextraction potential.