Effects of Intercropping System on Phytoremediation of Cadmium Contaminated farmland Soil in the Central Hanjiang River Basin

Kai Luo¹Kaixin Yan¹Xinkun Fu¹Haofei Xiong²Yonglin Sun^1*Yuqi Li^1*

• ¹Hubei University of Arts and Science, Xiangyang, China
• ²Xiangyang Academy of Agricultural Sciences, Xiangyang, China

Cadmium (Cd) pollution poses a global environmental challenge, especially in the rapidly developing central Han River Basin. Cd contamination in farmland soil there is becoming increasingly serious, warranting studies on remediation using hyperaccumulators. To explore the phytoremediation effects of different planting patterns on typical farmland soil (moisture soil) contaminated with Cd, two Cd hyperaccumulators (Sedum alfredii and Solanum nigrum) suitable for growth in Hubei Province and two common crops (celery and soybean) were selected for pot experiments involving monocropping and intercropping. The results showed that the absorption and accumulation of Cd by the two hyperaccumulators were as follows: CdS alfredii > CdS. nigrum, and the Cd concentrations in plants were as follows: Cdshoot >Cdroot, indicating a strong ability to transfer Cd from the root to the shoot. The Cd concentrations in each part of celery were as follows: Cdroot> Cdsteam> Cdleaf, while in soybean as follows: Cdroot> Cdleaf> Cdsteam. The Cd concentration in plants was significantly correlated with soil properties, negatively with pH (-0.68**) and positively with both total and available Cd in the soil (0.99**). The accumulation of Cd in plants in high - Cd soil treatments was significantly higher than that in low - Cd soil treatments (P < 0.05). The accumulation of Cd in plants ranged from 0.04 to 1.02 mg, and the Cd removal rate from the soil was between 1.96% and 19.68%. Intercropping enhanced the overall remediation efficiency. In the S. alfredii - celery and S. nigrum - soybean systems, the biomass of crops increased, the Cd absorption by the hyperaccumulators was significantly increased (P < 0.05). Both intercropping systems demonstrated relatively high soil Cd removal efficiency. Therefore, the two intercropping systems were suitable phytoremediation methods for Cd – polluted farmland soil in the central Han River Basin. Intercropping with the corresponding hyperaccumulators in fields of typical crops celery or soybean could reduce the food safety risk of these crops while simultaneously achieving phytoremediation.