Silicate-genotype interactions help improve stress tolerance of Glycine max and CO2 dynamics in saline soil

Abstract Soil salinity is limiting agricultural sustainability and rhizospheric carbon dynamics. The presence of soil silicates (Si) has been considered beneficial for plant growth; however, little is known about genotype-specific (G) responses in semi-silicious plants and CO 2 dynamics in the rhizosphere during saline (S) conditions. Here, we evaluate the G×Si×S interactions to understand how Si regulates genotype-specific salinity tolerance and rhizospheric carbon composition in 30 soybean ( Glycine max ) genotypes, both tolerant and sensitive. Si significantly increased above- and below-ground biomass in untreated control and salinity treatments. Four salt-tolerant genotypes showed significant Si uptake, biomass stability, photosynthetic assimilation, and carbon mobilization in the rhizosphere during salinity stress. Additionally, tolerant genotypes exhibited higher Si uptake capacity, enhanced soil carbonic anhydrase activity, and organic carbon accumulation in the rhizosphere compared to sensitive genotypes. Further, our machine learning models resolved the complexity of G×Si×S interactions, showing Si as a critical factor influencing plant growth and rhizospheric CO₂ dynamics.