Exploring Nitrogen Use Efficiency in Cereals: Insight into Traits, Metabolism, and Management Strategies Under Climate Change Conditions – A Comprehensive Review

Nitrogen (N) is an essential element for cereals growth and development, playing a crucial role in productivity and yield. Consequently, nitrogen fertilizers are extensively used in cereal cultivation. However, the excessive fertilizer application has led to significant environmental challenges, including nitrate leaching, greenhouse gas emissions coupled, and rising production costs due to increasing fertilizer prices. Additionally, has contributed to declining grain quality through reduced Nitrogen Use Efficiency (NUE). Enhancing NUE is crucial to address these issues, requiring comprehension understanding of its components and the physiological mechanisms governing nitrogen uptake, assimilation, and remobilization. This review synthesizes existing literature on NUE components and their influence on NUE variation. It explores nitrogen pathways in plants, interactions with soil properties, and the impact of root architecture and carbon–nitrogen metabolism. The review also highlights practical strategies for enhancing NUE, including agronomic innovations such as precision fertilization and irrigation, remote sensing, and site-specific management, and physiological approaches. Furthermore, emerging high-throughput tools, including remote sensing technologies and precision agriculture, are discussed. Given the challenges posed by climate change, such as heat stress, elevated CO₂ levels, and unpredictable rainfall, developing nitrogen-efficient cereals is essential for insuring sustainability, productivity, and global food security. This review underscores the need for integrated strategies that advanced research, agronomic techniques, and technological innovation. Additionally, limited progress has been made in integrating cutting-edge genetic tools, such as Omics and CRISPR technologies, with a deeper understanding of the complex interaction between genetic and environmental factors to enhance NUE of cereal crops.