Abstract:A lab incubation experiment and a pot experiment were conducted to investigate the effects of four recommended passivators (Yuanmeng, Zhutianfeng, Tianxiang 1, Yongqing), application dosage (recommended dosage, triple-recommended dosage), and the combination of the four passivators with lime (CaO) on immobilizing cadmium (Cd) in soil and Cd uptake by rice (Oryza sativa L.). The soil used for the experiments was Cd contaminated and collected from the suburb of Hangzhou, near Fuchun River. The four recommended passivators were selected from a previous experiment and have significant effects on immobilizing Cd and reducing Cd uptake by rice. The results show that soil pH increases significantly after the application of different passivators, and a greater increase is found under aerobic condition compared with flooded condition. Soil NH4NO3 extractable Cd decreases obviously after the application of the recommended dosages of passivators. Generally, the treatment of triple-recommended dosage shows a greater decrease for soil Cd extractability than the treatment of recommended dosage + CaO, followed by the treatment of recommended dosage. It indicates that soil NH4NO3-Cd is greatly affected by soil pH. The passivators of YM and TX1 show better Cd immobilization efficiency in general. Moreover, it is found that the application of lime and commercial passivators significantly reduces Cd concentration in brown rice along with an obvious decrease for soil Cd availability but without reduction and even a promotion for rice yield. The combination of the four passivators with lime shows a greater efficiency in reducing Cd concentration in brown rice and yield guarantees by increasing soil pH as well as providing some soil nutrients, especially calcium, organic matter and macronutrients.