Annual Research & Review in Biology

Climate change is increasing the frequency and severity of drought, salinity, heat stress, nutrient imbalance, and related constraints that threaten agricultural productivity and food security. Conventional adaptation approaches, including genetic improvement, irrigation technologies, and nutrient management, remain important but may address individual stresses rather than the interacting constraints increasingly experienced by crops. Silicon (Si), although generally regarded as a beneficial rather than an essential element, has considerable potential to support crop performance under multiple abiotic stresses. This review synthesises evidence on Si-mediated improvements in water relations, ion homeostasis, antioxidant defence, nutrient-use efficiency, membrane stability, and photosynthetic performance under drought, salinity, heat, and nutrient-related stress. It also examines the persistent gap between the expanding scientific evidence base and the limited inclusion of Si in mainstream fertiliser recommendations, extension programmes, and climate-smart agricultural frameworks. The available evidence indicates that Si responses are context-dependent and can vary with crop species, Si-accumulation capacity, stress intensity, soil conditions, source chemistry, dose, and management context. Therefore, Si should be considered a potentially strategic crop-management input rather than assumed to provide universal protection. Future progress requires stronger mechanistic understanding, identification of Si-efficient genotypes, long-term field validation, economic assessment, region-specific management guidance, and integration of Si into crop nutrition and climate-resilience strategies. These priorities could support evidence-based use of Si in sustainable crop production under increasing climatic stress.