Research Progress and Application Advances of Controlled-Release Nitrogen Fertilizers in Crop Production

Against the backdrop of global population and food security challenges, improving crop nitrogen use efficiency (NUE) is essential for sustainable agriculture. Conventional nitrogen fertilizers suffer from low utilization rates and significant environmental pollution. In contrast, controlled-release nitrogen fertilizers (CRNFs) synchronize nutrient supply with crop demand, offering significant advantages in enhancing yield, efficiency, and environmental sustainability. This review systematically outlines the developmental types of CRNFs, with a focus on their agronomic and ecological benefits. Key quantitative outcomes include yield increases of 3.0–15.3% in winter wheat, 12.38–22.67% in cotton, and maintained or improved maize yield even with a 20% reduction in nitrogen input. CRNFs also reduce ammonia volatilization by 20–43% in paddy fields. The review further elucidates the synergistic mechanisms through which CRNFs optimize root growth, enhance photosynthetic efficiency, and improve NUE. Major challenges such as high costs, release control precision, and coating material sustainability are critically assessed. Future directions include developing biodegradable coatings, smart fertilization systems, and stronger policy frameworks to facilitate broader adoption. This work provides a comprehensive theoretical and practical foundation for advancing the efficient and sustainable use of CRNFs in modern crop production.