Enhancing indigenous plant growth in metal(loid) contaminated soil using biochar.

Soil around mines contaminated with metal(loid) is not suitable for growing plants and it is necessary to select indigenous plants with tolerance for metal(loid) and ameliorate metal toxicity in soil using soil amendments. Therefore, the purpose of this study was to improve the soil environment to make it suitable for plant growth by treating chicken manure derived-biochar in soil contaminated with arsenic (As), cadmium (Cd), and lead (Pb). Biochar application increased soil pH and significantly reduced bioavailable As, Cd and Pb, thereby lowering toxicity in plants. Indigenous plant growth also increased by 30.2 and 91.3% in As and Pb contaminated soil under biochar treatment, respectively. Especially, Artemisia japonica Thunb. was effective for phytoextraction due to its accumulation of metals from contaminated soil, along with biochar application. Carex breviculmis R. Br. and Lespedeza cuneata (Dum. Cours.) G. Don. showed decreased above-ground Cd uptake by 57.6 and 44.9%, respectively, and As, Cd and Pb uptake by Juncus decipiens (Buchenau) Nakai decreased by 47.3, 65.7, and 94.1%, respectively, following biochar treatment. Juncus decipiens (Buchenau) Nakai, displayed tolerance in As, Cd and Pb contaminated soils and showed similar growth with or without biochar treatment, while the other three indigenous plant species failed to grow in the absence of biochar treatment. Therefore, J. decipiens is the most suitable candidate for the phytoremediation of metal-contaminated soils, and biochar further promoted plant health and growth.