Strategies for enhancing the phytoremediation of cadmium-contaminated agricultural soils by Solanum nigrum L

Field trials contribute practical information towards the development of phytoremediation strategies that cannot be provided by laboratory tests. We conducted field experiments utilizing the Cd hyperaccumulator plant Solanum nigrum L., on farmland contaminated with 1.91 mg kg−1 Cd in the soil. Our study showed that S. nigrum has a relatively high biomass. Planting density had a significant effect on the plant biomass and thus on overall Cd accumulation. For double harvesting, an optimal cutting position influenced the amount of Cd extracted from soils. Double cropping was found to significantly increase the amount of Cd extracted by S. nigrum. Fertilizing had no significant effect on plant biomass or on the Cd remediation of the soil over the short-term period. Our study indicates that S. nigrum can accumulate Cd from soils where the concentrations are relatively low, and thus has application for use in decontamination of slightly to moderately Cd-contaminated soil.

Research highlights
► S. nigrum L. is an effective phytoremediation plant for Cd-polluted soils.
► Agronomy practices that increase harvested biomass improve bioremediation efficiency.
► Double cropping of S. nigrum L. is an effective phytoremediation strategy.
► Field experiments are necessary to effectively assess phytoremediation techniques.