Porous Microspheres Promote Rice Growth and Restore the Health of Contaminated Soil by Activating Beneficial Soil Microorganisms

Heavy metals and pesticides are persistent and toxic contaminants that are frequently present in agricultural soils. In this study, we developed porous microspheres (MS) using sodium alginate and carboxymethyl cellulose as composite carriers. Compared with untreated contaminated soils (copper, Cu; hymexazol, HML), MS treatment (MS-Cu, MS-HML) significantly improved soil pH (by up to 2.21%), electrical conductivity (reduction up to 35.12%), and increased nitrogen and phosphorus contents (nitrate nitrogen by 7.19-41.79%, available phosphorus by 4.42-24.58%). Urease and sucrase activities were enhanced by 6.74-27.10% from weeks 2 to 7. Moreover, the relative abundance of soil fungal communities increased with enrichment of beneficial fungi associated with heavy metal sequestration and plant growth promotion. MS addition reduced the accumulation of copper and HML in rice roots by 18.46% and 18.67%, respectively, thereby alleviating adverse effects on seed germination and seedling growth. These findings offer a promising strategy for the sustainable remediation of contaminated soils.