Combined Application of Rice Straw and Fungus Penicillium Chrysogenum to Remediate Heavy-Metal-Contaminated Soil.

The search for cheap and environmentally friendly materials is essential for remediation of heavy-metal-contaminated agricultural soils. A pot experiment was undertaken to evaluate the application of rice straw and filamentous fungusPenicillium chrysogenum (P. chrysogenum)on the fractionation of copper (Cu) and cadmium (Cd), soil microbial properties, and Cu and Cd uptake by romaine lettuce (Lactuca sativa) in a contaminated agricultural soil. Rice straw was applied at three rates (0, 7.8, and 11.7 g kg−1soil), and in combinations with P. chrysogenum (1.0 × 106spores g−1soil). It was found that the combined treatment of rice straw andP. chrysogenumsignificantly decreased the acid-extractable Cu and Cd by 15.4–25.1% and 20.2–27.3%, and increased the oxidizable Cu and Cd by 16.1–18.0% and 72.1–98.4%, respectively. Soil microbial biomass and fresh weight of lettuce were also remarkably enhanced after rice straw plusP. chrysogenumaddition. Rice straw combined withP. chrysogenumwas more effective in reducing Cu and Cd uptake by lettuce than rice straw alone. The joint application of rice straw andP. chrysogenumremarkably reduced Cu and Cd concentrations in lettuce shoots by 13.6–21.9% and 32.9–41.7%, respectively. These results indicate that the combined application ofP. chrysogenumand rice straw is a promising method to alleviate the bioavailability of metals, and to improve soil microbial properties and plant yield in heavy-metal-polluted agricultural soils. [ABSTRACT FROM AUTHOR]