The growing demand for sustainable and environment-friendly materials has driven extensive research on biopolymers for applications in agriculture, food science, and environmental remediation. Among these, nanocellulose-hydrogel hybrids (NC-HHs) have gained significant attention as an innovative class of bio-based materials that uniquely combine the remarkable physicochemical properties of nanocellulose with the functional versatility of hydrogels. These hybrids are characterised by exceptional water retention, mechanical strength and biodegradability, enabling advances in precision agriculture, smart food preservation and contaminant remediation. This review provides a comprehensive understanding of the synthesis, properties, and multifunctional applications of NC-HHs, emphasising their innovative role in sustainability. In agriculture, NCHHs enhance soil moisture retention, support plant growth, and serve as carriers for controlled-release fertilizers, optimizing water and nutrient use efficiency. In the food industry, they enable intelligent packaging solutions that extend shelf life, monitor food freshness, and inhibit microbial growth. Additionally, NC-HHs present groundbreaking strategies for environmental remediation by effectively immobilizing pollutants in water and soil. Beyond summarizing recent advances, this review presents an in-depth mechanistic perspective on the interactions between NC and HH, critically evaluating their structure-property relationships, functional adaptability and application-specific performance. By integrating recent advances in nanocellulose functionalisation, polymer chemistry and the development of responsive hydrogels, this review critically examines the key technological innovations and future prospects of NC-HHs, underscoring their transformative potential in addressing global challenges related to food security, environmental sustainability, and sustainable agricultural practices.

Microplastic contamination of low-density polyethylene mulch and nutrient loss from fertilizers present significant challenges in the crop-growing. In this study, the focus was on creating a biodegradable film that combines the advantages of plastic film, thermal insulation and water retention, as well as the controlled release of fertilizer. A key innovation was the efficient introduction of low molecular weight and low dispersibility of poplar lignin into chitosan and polyvinyl alcohol matrices. The lignin was extracted using deep eutectic solvents of binary carboxylic acids (choline chloride and maleic acid). The refined lignin was used as a superhydrophobic additive to improve the mechanical properties, hydrophobicity, and controlled nutrient release properties of the films through cross-linking. The mulch attained a tensile strength of 37.6 MPa, an elongation of 644.1 %, and a precise release of 53.1 % urea over 30 d at the ideal lignin content ratio (10 %). Furthermore, the film proficiently regulated soil temperature and moisture content. Successful enhancement of cabbage growth was achieved by actual measurements. This discovery provides innovative ideas for the development of nutrient slow- release high-strength integrated agricultural mulching films to promote sustainable, high-quality green agriculture.

Through a paddy soil column experiment, we comprehensively evaluated the effects of three irrigation practices and three nitrogen (N) fertilizer application strategies on NH3 volatilization, N2O emissions, and rice yields during the rice growing season to identify the optimal irrigation and fertilization combination technique to reduce both NH3 and N2O losses in paddy soil while sustaining rice yield. In addition, we integrated molecular biology techniques (Quantitative PCR) to establish correlations between environmental factors and the abundance of N cycling-related soil microbial functional genes, revealing the intricate interactions between NH3 volatilization and N2O emissions under varied coupling irrigation and fertilization schemes. Our results clearly showed a trade-off relationship between N2O and NH3 emissions under water-saving irrigation practices (controlled irrigation (CI) and intermittent irrigation (II)) coupling with traditional fertilizer urea. Compared with continuous flooding (CF) practice, both CI and II treatments reduced NH3 volatilization by 36.3-73.9%, while increasing N2O emissions by 1483.2-2246.2% during the rice growing season. Notably, the combination application of CRF under CI mode (CI-CRF) significantly reduced NH3 volatilization by 65.0% during the rice growing season, compared to the conventional II-Urea approach. Although the impact on N2O emissions was modest, CI-CRF strategy still achieved a 4.6% reduction in N2O emissions, thus tackling the trade-offs between two important environmentally damaging gases under water-saving irrigation. The suppression of NH3 volatilization was primarily attributed to the CI-CRF strategy lowering NH4+-N concentrations in flooding water, while the reduction in N2O emissions was associated with an increase in soil nirS and nosZ gene abundances. Further estimates indicated that the CI-CRF strategy could potentially reduce NH3 volatilization by 259.2 Gg N yr-1 and N2O emissions by 3.1 Gg N yr-1 in single-crop paddy field in China, compared with traditional II-Urea approach. Therefore, the optimal reduction of gaseous N loss, coupled with yield enhancement, could be achieved through the synergistic strategy of CI-CRF in single-crop rice cultivation ecosystems. Future studies should focus on fieldbased experiments that explore the long-term effects of CI-CRF combinations under varying soil types, climates, and rice cultivation systems.