Effects of intercropping peaches with Hylotelephium spectabile on Cd uptake, rhizosphere soil properties and phytoremediation efficiency

Abstract

An effective strategy for the safe utilization of Cd-contaminated soil involves the cultivation of crop varieties with low Cd accumulation in conjunction with a hyperaccumulator such as Hylotelephium spectabile. In this study, the peach cultivar ‘Lvhuajiu’ was intercropped with two ecological types of H. spectabile, ‘Liaoning (LN)’ and ‘Hebei (HB)’, to explore plant Cd uptake and rhizosphere soil properties. The results revealed that under pot intercropping conditions, the roots of the ‘Lvhuajiu’ peach tree engaged in nutrient competition, which increased biomass production. A maximum of 68.02% reduction in Cd content was observed in peach tree roots under open intercropping with H. spectabile LN. H. spectabile absorbed more available Cd under intercropping, and LN had a higher Cd absorption capacity than HB. The removal efficiency under restrictive intercropping (0.34%–0.50%) was slightly lower than that under open intercropping (0.62%–0.67%). Intercropping systems were highly abundant in Proteobacteria, Acidobacteria, Bacterodietes, and Actinobacteria, which are essential for the elimination of Cd and cycling of nutrients. Furthermore, the field experiment showed that peach and H. spectabile intercropping could achieve a 4.11% removal efficiency per year under water-soluble chitosan addition. Besides, Cd concentrations in the peaches under all treatments remained below the national food standard of 0.05 mg·kg⁻¹. In conclusion, intercropping peaches with H. spectabile facilitates the safe utilization of Cd-contaminated soil by modifying rhizospheric soil properties, underscoring its considerable potential for a wide range of applications.