Enhancing remediation of As-contaminated orchard soil through intercropping Pteris vittata with low-accumulating peach trees.

In recent years, the frequent occurrence of heavy metal contamination in orchard soils has posed a threat to the quality and edible safety of fruits. To investigate the remediation efficiency and explore the application potential of intercropping patterns featuring hyperaccumulator Pteris vittata in orchards, this study focused on peach trees, a major economic fruit crop, and conducted a systematic examination of intercropping in As-contaminated orchard soil. First, the screening pot experiment compared the As accumulation ability of 10 main peach cultivars in local areas. The results showed that the As content in the peach roots was the highest, followed by the leaves and stems. Lvhua 9 (LH9) and Ruipan 13 (RP13) peach trees had better growth and lower As accumulation. Second, a pot intercropping experiment of P. vittata and low-As peach cultivars (LH9 and RP13) was conducted by the rhizosphere bag method (monoculture, restricted intercropping, opening intercropping). Compared with monoculture, intercropping increased the As content in P. vittata (8.29-134%) and decreased the As content in peach (31.1-69.1%) by root interaction. In addition, intercropping significantly increased the abundance of As-resistant Sphingomonas in the rhizospheres of the two peach cultivars and P. vittata (21.4% to 108%), and the As removal rate was increased (up to 198%). Finally, in the field experiment, the intercropping of P. vittata and LH9 significantly promoted the growth, photosynthesis, and As uptake of P. vittata, especially in rainy July and August. Moreover, the yield of peach fruits was not notably affected, and their As content met national standards. In conclusion, intercropping P. vittata with selected peach cultivars in As-contaminated orchard soils effectively enhances As remediation efficiency while maintaining fruit quality and safety, demonstrating its promising application potential for sustainable orchard management.