Mitigating cadmium contamination in rice: insights from a large-scale meta-analysis of amendment effects

Cadmium (Cd) pollution in rice is a health hazard. to humans. Amendments often decreases soil Cd bioavailability and Cd accumulation in rice plants. However, a complete and quantitative understanding of the effects of soil amendment on soil properties, Cd availability, rice yield, and Cd accumulation in rice is lacking.

A meta-analysis was conducted using data obtained from 436 peer-reviewed articles to evaluate the impact of 11 types of amendments on different variables in a soil-rice system polluted with Cd.

Clay minerals, lime, phosphate fertilizers, nanomaterials, industrial by-products, biochar, manure, composite materials, other organic materials, and other inorganic materials significantly reduced the rice Cd content. Amendments decreased brown rice Cd concentrations by 33.4%, increased crop yields by 12.1%, and decreased the soil available Cd by 26.4%, on average. However, no amendments led to economic improvements. The amendments increased soil pH, CEC, and SOC by 7.94%, 14.73%, and 11.97%, respectively, affecting soil Cd forms. The selection of amendments principally determines their inhibitory effects on Cd in brown rice. Subgroup analysis revealed that during intense precipitation (> 2000 mm), amendments were more efficient at decreasing Cd content in brown rice. However, their effectiveness was diminished in loamy soils. Soil pH was essential for regulating accessible Cd in acidic soils.

Amendments successfully lowered Cd levels in rice grains and enhanced soil quality while maintaining rice yield.