Abstract: In order to verify the remediation effect of the combined modifier on lead polluted soil, pot experiments were used to study the effects of different concentrations of modifiers (0, 600, 900 and 1 200 mg·kg^-1) on soil organic matter content, pH, microbial community structure, lead accumulation and nutritional quality of the radish (Raphanus sativus L.) planted in two levels of lead polluted soil (800 mg·kg^-1 and 1 200 mg·kg^-1). The results showed that after applying 900 mg·kg^-1 modifier, the organic matter contents of the 800 mg·kg^-1 and 1 200 mg·kg^-1 of the lead polluted soil increased by 21.32% and 25.35%, respectively. In addition, the bacterial quantity, actinomycetes quantity, and total microorganism amounts of the two levels of the lead polluted soil significantly increased. However, applying the combined modifier had no significant effect on the pH of the soil. Moreover, after applying 900 mg·kg^-1 combined modifier, the lead contents in the fleshy root of the radish planted in the 800 mg·kg^-1 and 1 200 mg·kg^-1 of lead polluted soil decreased by 20.35% and 27.69%, respectively. Furthermore, the contents of vitamin C, soluble sugar, and dry matter of radish were largely improved. These data indicated that the security and nutritional quality of the radish planted in the lead polluted soil were obviously improved comparing with no modifier application.

Key words: radish, lead, heavy metal, modifier, nutritional quality