Effects of Sedum plumbizincicola-Oryza sativa rotation and phosphate amendment on Cd and Zn uptake by O. sativa.

In a pot experiment, hyperaccumulator Sedum plumbizincicola and low-cadmium accumulating Oryza sativa cultivar "Zhongxiang No. 1" were planted in rotation on a heavy metals-polluted soil, and calcium magnesium phosphate (Ca-P) and rock phosphate (P-R) were amended, aimed to study the effects of the rotation and phosphate amendment on the growth of the two plants and the zinc-and cadmium accumulation in their shoots. After the amendment of 50 g P-R∙kg^-1, the Zn and Cd uptake by S. plumbizincicola was 11.5 mg∙pot-1 and 0∙79 mg∙pot^-1, respectively, being significantly higher than that after the amendment of 4 g Ca-P∙kg^-1. After the planting of S. plumbizincicola, the Zn and Cd concentrations in "Zhongxiang No. 1" increased, but the amendment of Ca-P decreased the accumulation of Zn and Cd in rice shoot significantly. The rotation with S. plumbizincicola and the amendment of Ca-P and P-R could immobilize the Zn and Cd in the contaminated soil as indicated by the quantitative change of NH₄OAc-extractable Cd and Zn, and the efficiency of amendment with Ca-P was better than that of amendment with P-R. Field trial showed that amendment with Ca-P could not only increase the rice yield, but also reduce the Zn and Cd accumulation in rice shoot to a certain extent. [ABSTRACT FROM AUTHOR]