Evaluating the Effectiveness of Biogenic Silicon Sources and Na-Silicate as Silicon Fertilizers in Mitigating Boron Toxicity in Maize

Abstract Excess boron (B) in soil can severely damage plant tissues, reducing growth and yield. This study evaluated the effectiveness of biogenic silicon (Si) sources; rice husk (RH), modified rice husk (MRH), and RH-derived Nano-Si compared with a conventional Si source, Na-silicate, in mitigating B toxicity in maize. Maize plants were grown in soil containing 30 mg kg -1 B under screenhouse conditions. MRH and Nano-Si were characterized using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). All Si sources were applied at 200 mg Si kg -1 soil. Structural analyses indicated that MRH consisted of particles >100 nm, whereas Nano-Si had spherical particles <100 nm. XRD and FTIR confirmed the predominantly amorphous Si structure in both materials, verifying the successful synthesis of Nano-Si from rice husk. Application of RH and MRH produced the highest dry weights. All Si treatments significantly reduced membrane permeability relative to the control (23.2%) and decreased B concentrations in young and old plant tissues. In young plant parts, Si concentrations increased under most treatments, except RH, whereas differences in old tissues were not statistically significant. Biogenic Si sources alleviated B toxicity by reducing B uptake, improving membrane stability, and enhancing ionic balance. Among the treatments, RH and MRH were most effective, suggesting that Si-rich agricultural by-products can serve as sustainable alternatives to conventional Si fertilizers. These findings highlight the potential of biogenic Si in improving crop tolerance to B toxicity while promoting sustainable nutrient management in maize cultivation.