Remediation of Arsenic contaminated soil using malposed intercropping of Pteris vittata L. and maize.

Intercropping of arsenic (As) hyperaccumulator and cash crops during remediation of contaminated soil has been applied in farmland remediation project. However, little is known about the fate of As fractions in the soil profile and As uptake within the intercropping plants under field condition. In this study, As removal, uptake, and translocation were investigated within an intercropping system of Pteris vittata L. (P. vittata) and maize (Zea mays). Results indicated that the concentration of As associated with amorphous Fe (hydr)oxides in the 10-20 cm soil layer was significantly lower under malposed intercropping of P. vittata and maize, and As accumulation in P. vittata and biomass of P. vittata were simultaneously higher under malposed intercropping than under coordinate intercropping, leading to a 2.4 times higher rate of As removal. Although maize roots absorbed over 13.4 mg kg-1 As and maize leaves and flowers accumulated over 21.5 mg kg-1 As (translocation factor higher than 1), grains produced in all intercropping modes accumulated lower levels of As, satisfying the standard for human consumption. Our results suggested that malposed intercropping of a hyperaccumulator and a low-accumulation cash crop was an ideal planting pattern for As remediation in soil. Furthermore, timely harvest of P. vittata, agronomic strategies during remediation, and appropriate management of the above ground parts of P. vittata and high-As tissues of cash crops may further improve remediation efficiency.