Role of nitrogen and silicon in improving growth, yield, and stress tolerance of rice (Oryza sativa L.): A review

Abstract

Rice (Oryza sativa L.) is a staple food crop that feeds over half of the global population and plays an essential role in ensuring food and nutritional security. However, rice cultivation and its productivity are increasingly challenged by climate change, soil degradation, water scarcity, pest and disease infestations. Among the various agronomic strategies, integrated nutrient management, particularly involving nitrogen (N) and silicon (Si), has emerged as a promising approach to address these challenges. Nitrogen is a vital macronutrient that supports plant metabolism, vegetative growth, tillering, chlorophyll synthesis, and grain development. Conversely, silicon, though not classified as an essential, plays a complementary role by strengthening structural integrity, improving nutrient uptake, regulating enzymatic and hormonal activities, reinforcing cell walls, boosting photosynthesis efficiency, and increasing resistance to both abiotic and biotic stresses. The combined application of N and Si has shown a synergistic effect, where it improved the rice growth, yield attributes, stress resilience, and defense system of the plant more effectively than either nutrient alone. Moreover, it also enhances the enzymatic activity while mitigating lodging and heavy metal uptake. Therefore, optimizing the combined use of both nitrogen and silicon in rice cultivation is important for achieving higher productivity and greater resilience against stress conditions.