Agricultural sustainability implications in using nanocellulose composite for delaying nitrogen release

Nitrogen fertilizer is a crucial macronutrient for the growth and metabolism of crops. However, conventional fertilizers' low nitrogen use efficiency (NUE), due to their high-water solubility and volatility, has consequences for unsustainable farming practices, and it has driven the highly efficient biopolymer-based fertilizers. Slow-release nitrogen fertilizer (SR-N), an environmentally friendly fertilizer, has been designed to release nutrients gradually, which can be absorbed by plant roots. This article reviews the nanocellulose used as a matrix and coating material in SR-N designs and its implications for sustainable agriculture. The advantages of nanocellulose drive the interest as an abundant, biodegradable, renewable material with high hydrophilicity and ease of modification. Findings indicate that nanocellulose and nitrogen can be used as nutrient suppliers to enhance the growth and diversity of soil microbes. The abundance of soil microbes can accelerate nitrogen fixation, convert it into nutrients that plants can absorb, and decompose organic matter into nutrient-rich humus. The high content of hydroxyl (-OH) groups in nanocellulose results in a high-water absorption capacity, thus maintaining soil moisture. Ease of surface modification, such as adding a charge, will provide new properties crucial for delaying nitrogen release. These aspects stimulate growth, increase productivity, and regulate the chemical composition of crop commodities. Delayed nitrogen release has consequences for reducing emissions in the agricultural sector. Future directions recommend considering the aspects: i) Cost and scalability, ii) Application methods, iii) Field variability and application, and iv) Regulation and public acceptance.