Alleviation of heavy metal accumulation in rice: A synergistic planetary health approach of organic amendment and phytoremediation in cadmium contaminated soil

• Vermicompost (VC) and duckweed (DW) increase Cd-stressed rice morphological growth • VC and DW boost chlorophyll content and antioxidant enzyme activities of rice leaves • Optimal VC (4.4%) and DW (77.0 g m -2 ) reduce grain Cd level and increase grain yield Cadmium (Cd) contamination in agricultural soils poses serious risks to crop productivity, food safety, and public health. Therefore, we aimed to mitigate the detrimental effects of Cd stress on plant growth by utilizing organic substrates and phytoremediation methods. In this study, we performed a pot trial to investigate the potential mediating effects of vermicompost (VC) and floating duckweed (DW) on Cd uptake by rice cultivated in Cd-contaminated soil. We applied five distinct levels of VC and DW to optimize the rates of VC-DW applications. Our study revealed overall increases in plant height, root length, panicle length, number of filled-grain panicles per plant, 1000-grain weight, and both above- and below-ground biomass in the presence of VC and DW. Furthermore, VC and DW effectively mitigate Cd's toxic effects on plant growth and chlorophyll content, resulting in an increased grain yield. For example, treatment VC 4.4 DW 340 caused significant increases in rice grain g pot -1 (30.4%) and decreases in grain Cd content (80.0%) compared to the untreated control. We also found that using VC and DW efficiently minimized the production of malondialdehyde by increasing the activities of superoxide dismutase and catalase. The lower Cd content in rice grains in the presence of optimal VC (4.4%) and DW (187.0 g m -2 ) rates suggests that applying these precise rates of VC and DW for cultivating rice in Cd-polluted soil could be an effective strategy to address this global planetary health problem.