Recovering a copper mine soil using organic amendments and phytomanagement with Brassica juncea L.

A 3-month greenhouse experiment was carried out for evaluating the effect of an amendment mixture and mustards on the chemical characteristics of a mine soil and the metal uptake by plants. A settling pond soil was amended with increasing percentages of a technosol and biochar mixture and vegetated with Brassica juncea L. Adding amendments and planting mustards increased the soil pH from 2.83 to 6.18 and the TSC from u.l to 131 g kg(-1) and generally reduced the CaCl2-extractable metal concentrations in the soil. However, the amendments increased the pseudo-total soil concentration of Ni from 9.27 to 31.9 mg kg(-1), Pb from 27.9 to 91.6 mg kg(-1) and Zn from 46.5 to 577 mg kg(-1). The technosol and biochar mixture increased the shoot biomass from 0.74 to 2.95 g and generally reduced the metal concentrations in plants, meaning B. juncea as a potential candidate for phytostabilization of mine soils.