Abstract:In order to provide scientific basis for food safety in rice fields, a field trial was conducted in Changsha, Hunan Province to investigate the effects of biochar amendment on the form of cadmium (Cd), the uptake and distribution of Cd and soil fertility of rice field polluted by Cd. Five biochar application treatments (0, 10, 20, 30 and 40 t/hm2) were set to analysis the effects of the biochar amendment on the migration of Cd in the soil and the distribution of Cd in the rice organs. The results showed that the biochar reduced the accumulation of Cd in the rice organs by passivating the acid-soluble Cd into the reducible Cd in the soil, and the amount of passivation increased with the increasing of biochar, the acid-soluble Cd decreased by 3.83%~19.08% in biochar treatments compared with CK. After the biochar applying, the translocation coefficient of Cd for stem to root and brown rice to stem were decreased by 4.23%~9.30% and 1.39%~8.33%, respectively. The decision analysis showed that the content of the acid-soluble Cd in soil directly affected the Cd content in the brown rice, and was regulated by soil pH and organic carbon in the soil. In conclusion, biochar amendment could improve the soil fertility and decrease the Cd bioavailability in the Cd polluted rice field. The addition of 20 t/hm2 biochar could be taken as a reference standard for remediation of the rice field polluted by Cd around the research area.