S Sasmitha

Rice (Oryza sativa L.) is a staple food for over 3.5 billion people worldwide; however, its production is increasingly threatened by climate change-induced drought, soil salinity and heat stress. Silicon (Si) is a beneficial and quasi-essential element and has been researched extensively for mitigating the effects of abiotic stresses in rice. Recent advances have focused on developing highly bioavailable Si delivery systems, including nano-silica nanoparticles (SiNPs) and Si-based biostimulants. This review synthesises current knowledge on Si dynamics in soil–plant systems, the physicochemical properties of nano-silica and major application strategies reported for rice cultivation. Mechanistic areas covered include enhancement of abiotic stress tolerance (drought, salt and heat stress), activation of the antioxidant defence, maintenance of photosynthesis, nitrogen-use efficiency (NUE), hormonal signalling mechanisms and rice blast (Magnaporthe oryzae) and sheath blight (Rhizoctonia solani) resistance. Environmental safety issues, regulatory considerations and future perspectives in precision and sustainable agriculture are also discussed. The on-farm adoption barriers and key research needs are highlighted throughout. Unlike earlier reviews focused primarily on conventional Si fertilisation, this review emphasises recent advances in nano-silica technologies, Si-based biostimulants and their relevance to climate-resilient rice production.