APPLICABILITY OF FLY ASH, INTERMEDIATE MATERIAL, AND ZEOLITE FOR IMPROVING SOIL FERTILITY AND YIELD OF TWO IRANIAN RICE CULTIVARS GROWN IN CADMIUM-CONTAMINATED SOIL

Cadmium (Cd) as a highly toxic heavy metal can cause seriously harmful to human health. The present study aimed to investigate the effects of fly ash, intermediate materials, and zeolite on the yield performance of two cultivars of Iranian rice (Anbarbo and Champa) and the remediation of Cd-contaminated soil. The experiment was carried out in two crop years, 2019-2020 and 2020-2021, in both forms of field and pot cultivation. The research treatments included fly ash, intermediate materials, zeolite, and genotype. Plant variables were analyzed by a split-plot method as a randomized complete block design, and soil variables were analyzed by a random complete block method. Results showed that intermediate material was significantly associated with dry weight, biomass, root Cd content, stem Cd content, seed Cd content, and rice yield (p<0.01). Genotype also significantly affected dry weight, biomass, root Cd content, and rice yield (p<0.01), and the Champa variety had the highest yield. The field and pot experiment results showed that the intermediate material was significantly associated with the highest amount of dry weight and the lowest amount of root, stem, and seed Cd content. Fly ash significantly increased soil pH, cation exchange capacity, phosphorus, and reduced soil Cd content (p<0.01). However, the highest amount of available soil potassium was observed in the zeolite treatment. The impact of zeolite on contaminated soil needs further exploration. In conclusion, this study suggested that one of the beneficial strategies to improve rice yield and the fertility of contaminated soils is using waste materials such as fly ash and its derivatives.