Abstract:

Soil acidification exacerbates cadmium（Cd）activation and migration，posing a threat to the safe production of rice. This study conducted a field experiment in a Cd-contaminated paddy field in Zhejiang，China，to investigate the effects of five soil amendments：silicon-calcium-magnesium-potassium（SCMP），Ningliang shengwu，Fengshouyan，Tebei calcium，and lime，on ameliorating soil acidification and regulating Cd bioavailability. The results demonstrated that，except for SCMP，all other amendments significantly（p<0.05） increased soil pH value（from 0.50 to 1.28 ）and reduced the total exchangeable acid content by 74.68%-100.00%，with Fengshouyan showing the most pronounced effect. Additionally，all amendments significantly decreased bioavailable Cd content in soil and the Cd content in brown rice by 15.22%-58.94% and 17.04%-46.09%，respectively，among which Ningliang shengwu exhibited the optimal efficacy. In summary，Fengshouyan and Ningliang shengwu demonstrated superior performance in improving acidic soil and reducing Cd bioavailability，and their combined application was recommended. This study provided a scientific basis for the remediation of Cd-contaminated acidic paddy fields.

Key words: soil acidification, cadmium bioavailability, soil amendment, field experiment, brown rice cadmium accumulation