Influence of soil amendments on the growth and cadmium accumulation of rice in high-cadmium-contaminated agricultural soils: a pot experiment

High-selenium areas are often accompanied by high soil cadmium (Cd) concentrations, which increases the potential risk to agricultural product safety in these selenium-rich areas. Therefore, this study investigated Cd absorption and accumulation in rice plants and explored the effects of rice plant growth and development when different soil amendment combinations were added to the high-Cd soils. Combination design experiments were conducted in different proportions, using biochar, trace element fertilisers and clay minerals as raw materials. Investigations showed that soil amendments significantly improved chlorophyll, root vitality and antioxidant enzyme activity. We also observed that all soil amendment treatments added to the high-Cd soils reduced the water-soluble and ion-exchangeable cadmium content in these soils. However, the maximum effect treatment was 21.46% lower than that of CK (no use of soil amendment). Furthermore, T2 (1.2% rapeseed meal + 0.3% calcium-magnesium-phosphate fertiliser + 2.4% sepiolite + 0.1% silicon fertiliser) and T8 (3% rice biochar + 0.3% silicon-calcium-potassium-magnesium fertiliser + 1.8% vermiculite + 0.1% silicon fertiliser) treatments could significantly reduce malondialdehyde content in leaves, decreasing Cd transfer in the plant. Moreover, while the Cd content in roots, stems and leaves, respectively, was reduced by 57.34% and 71.64% following the T2 treatment, a decrease by 46.20% and 67.03% following the T8 treatment was observed. After comprehensive analysis and comparison, we propose that the T2 and T8 treatments can protect rice growth and reduce Cd accumulation of plant in naturally high-Cd areas.