Effect of Phosphate and Zinc Amendment at Paddy Season on Cadmium Absorption in Rice and Sedum plumbizincicola

Rotation or intercropping of hyperaccumulator and crop is an important way to realize the production while remediation on heavy metal polluted soils. The influence of phosphate (P) and zinc (Zn) amendments at rice growth season on cadmium (Cd) uptake in rice and succeeding Sedum plumbizincicola was studied in a pot experiment using Cd contaminated acid red soil through the rotations of rice and S. plumbizincicola. The results show that at the high P (400 mg·kg^-1) treatment soil CaCl₂ extractable Cd decreased compared with the control (100 mg·kg^-1), and the Cd concentration in rice straw was not effected obviously, but the Cd transfer coefficient from straw to grain was significantly decreased in the rice season. The soil CaCl₂ extractable Cd concentration reduced under Zn treatment, and the Cd concentration in brown rice was reduced from 0.21 mg·kg^-1 (control) to 0.15 mg·kg^-1. The P and Zn treatment at rice season had no obvious influence on the shoot biomass and Cd concentration of S. plumbizincicola at next season. Zn treatment at rice season increased Zn accumulation in rice and S. plumbizincicola. The P and Zn treatment at rice season could reduce the risk of Cd accumulation in rice and had no obvious effect on Cd removal by succeeding S. plumbizincicola. So adding Zn and P can be regarded as an adjustable way to treat Cd polluted soil with production while remediation.