Effect of intercropping and biochar application on cadmium removal capacity by corchorus olitorius and zea mays

Heavy metals in farmlands represent a severe concern for food security. Particularly with the ongoing increase in its release to the environment. In this regard, intercropping is a natural way to remediate polluted soil via enhancing the phytoremediation efficacy of heavy metals. Besides, biochar amendments were also found to be an effective strategy for the removal of heavy metals from polluted soils. Thus, the present study aimed to compare intercropping and biochar amendments in reducing the potential risk of Cd in both Corchorus olitorius and Zea mays in alkaline soils. The results showed that intercropping with biochar amendment increased the metal removal equivalent ratio by 22.93% as compared to intercropping alone i.e., without biochar amendment. When biochar was applied with the intercropping system, C. olitorius phytoremediation ratio significantly increased by 198.93% as compared to the intercropping without biochar treatment. In contrast, phytoremediation ratio was significantly increased by 112.24% and 128.94% in case of Z. mays in the monocropping and intercropping systems, which suggested that intercropping is a promising eco-friendly strategy to remediate Cd-contaminated soil with biochar amendment. Meanwhile, the biochar application significantly reduced the soluble and reducible Cd in both cropping systems, while the oxidizable Cd significantly increased with biochar amendment. Further, biochar significantly reduced the residual Cd in the intercropping system, indicating that biochar treatment may enhance Cd removal from contaminated soils. C. olitorius intercropping with biochar application had a positive effect on improving Cd remediation efficiency and reducing the Cd content in Z. mays crops. This practice could be applied in Cd-contaminated soil remediation along with crop production in farmland.