Phytoremediation potential of wheat intercropped with different densities of Sedum plumbizincicola in soil contaminated with cadmium and zinc

Intercropping technology is applied widely in crop cultivation to help remediate soil polluted with heavy metals. To investigate the feasibility and potential of intercropping hyperaccumulator plants with crops in cadmium (Cd)- and zinc (Zn)-contaminated soil, a pot experiment was conducted to examine plant growth and the contents of Cd and Zn in the soil following intercropping of wheat and Sedum plumbizincicola. Five treatments were examined: control (wheat monoculture: 36 seedlings per pot), and intercropping of wheat with different planting densities of S. plumbizincicola (3, 6, 9 and 15 seedlings per pot, respectively). Results showed a decrease in soil pH, and in soil and wheat contents of Cd and Zn with increasing planting density of S. plumbizincicola, while the removal rate of Cd and Zn increased. Meanwhile, excessive planting (15 seedlings per pot) inhibited wheat growth by 27.34% compared with the control, and overall, the optimal planting density was 9 seedlings per pot, resulting in effective remediation with only a moderate effect on wheat growth. These findings highlight the value of intercropping S. plumbizincicola with wheat as a means of improving remediation of soil contaminated with heavy metals (Cd and Zn). •Intercropping of wheat and S. plumbizincicola decreased soil pH and soil Cd and Zn.•Removal of soil Cd and Zn increased with increasing density of S. plumbizincicola.•A proper planting density of S. plumbizincicola was 9 seedlings per pot.•Intercropping with S. plumbizincicola reduced heavy metal contamination.