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The study was aimed at evaluating the effect of nanosilica and different sources of silicon on soil properties, total bacterial population and maize seed germination. Nanosilica was synthesised using rice husk and characterised. Silica powder was amorphous (50 nm) with >99.9% purity. Sodium silicate treated soil inhibited plant growth promoting rhizobacteria in contrast to nanosilica and other bulk sources. Surface property and effect of soil nutrient content of nanosilica treatment were improved. Colony forming unit (CFU) was doubled in the presence of nanosilica from 4 × 105 CFU (control) to 8 × 105 CFU per gram of soil. The silica and protein content of bacterial biomass clearly showed an increase in uptake of silica with an increase in nanosilica concentration. Nanosilica promoted seed germination percentage (100%) in maize than conventional Si sources. These studies show that nanosilica has favourable effect on beneficial bacterial population and nutrient value of soil.

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In this study, maize treated with nanosilica (20-40 nm) is screened for resistance against phytopathogens such as Fusarium oxysporum and Aspergillus niger and compared with that of bulk silica. The resistivity is measured for disease index and expression of plant responsive compounds such as total phenols, phenylalanine ammonia lyase, peroxidase and polyphenol oxidase. The results indicate that nanosilica-treated plant shows a higher expression of phenolic compounds (2056 and 743 mg/ml) and a lower expression of stress-responsive enzymes against both the fungi. Maize expresses more resistance to Aspergillus spp., than Fusarium spp. These results show significantly higher resistance in maize treated with nanosilica than with bulk, especially at 10 and 15 kg/ha. In addition, hydrophobic potential and silica accumulation percentage of nanosilica treated maize (86.18° and 19.14%) are higher than bulk silica treatment. Hence, silica nanoparticles can be used as an alternative potent antifungal agent against phytopathogens.

Magnesia (MgO) nanoparticles were produced from magnesite ore (MgCO3) using ball mill. The crystalline size, morphology and specific SSA were characterized by X-ray diffraction analysis, transmission electron microscopy and Brunauer-Emmett-Teller method, respectively. MgO nanoparticle-incorporated nylon 6 solutions were electrospun to produce nanofiber mats. Surface morphology and internal structure of the prepared hybrid nanofiber mats were examined by scanning electron microscopy and high-resolution transmission electron microscopy, respectively. The fire retardancy and antibacterial activity (Staphylococcus aureus and Escherichia coli) of coated fabrics made from MgO/nylon 6 hybrid nanofiber are better than those from nylon 6 nanofiber.