Effect of Peanut Intercropping on Arsenic Uptake and Remediation Efficiency of Plants in Arsenic-Contaminated Soil

Phytoremediation is an economically viable and environmentally friendly technique among various arsenic-contaminated soil remediation technologies. Field plot experiments were conducted to investigate the effects of peanut intercropping with sunflower, lucerne, and jute on the growth and development of intercropped crops and the efficiency of arsenic (As) remediation in polluted soil within the intercropping system. The results indicate that intercropping peanuts with other crops can enhance the biomass and yield of the crops. The land equivalent ratios (LER) of the three intercropping patterns were 1.03, 1.70, and 1.17, respectively. The intercropping pattern also influences the absorption and accumulation of As in crops. Total arsenic accumulation in peanuts intercropped with jute reached 493 μg·plant−1, which was significantly higher by 29.5% compared to peanut monoculture. Additionally, the translocation factor (TF) and bioaccumulation factor (BCF) of peanut seeds were significantly higher in peanut-jute intercropping compared to other treatments, but the As content of peanut seeds in all treatments complied with national food safety standards (GB2762-2022, 0.5 mg·kg−1). Intercropping of peanuts altered the pH and Eh values of rhizosphere soil, further influencing the percentage content of various forms of As in the soil, and reducing the mobility and effectiveness of As. The metal removal equivalent ratios (MRER) for the three intercropping patterns were 1.30, 2.11, and 1.26, respectively. The intercropping of peanuts and lucerne resulted in an MRER of 2.11. It indicates that peanut intercropping has a significant promotion and high restoration efficiency on the growth and development of lucerne. Therefore, among the three patterns, the peanut intercropping lucerne pattern has the best effect in applying to contaminated soil, and can better realize the integration of economic and ecological benefits.