In the world of modern agriculture, resource conservation and efficiency are pivotal concerns. Farmers constantly seek ways to maximize crop yield while minimizing the waste of water and fertilizer—two resources that are inextricably linked to the success of their harvests and the sustainability of their practices. In what could be a significant stride towards addressing these challenges, a groundbreaking study has been published in “Carbohydrate Polymers”. This study outlines the development of an innovative slow-release fertilizer with an integrated water-retaining function, created through the modification of carboxymethyl chitosan. This novel approach promises to offer a multifaceted solution to the problem of agricultural water scarcity and low fertilizer utilization rates.

DOI: 10.1016/j.carbpol.2023.121744

The publication in “Carbohydrate Polymers”, identifiable through the DOI 10.1016/j.carbpol.2023.121744, provides comprehensive insights into the development and application of a novel nutrient-water carrier system that uses carboxymethyl chitosan superabsorbent resin networks. The technology incorporates solution polymerization and semi-interpenetrating network technology to load urea aldehyde into the resin network, which ultimately leads to the slow release of nutrients encapsulated within.

The main revelation of the study is the simultaneous slow release of nutrients and water achieved using modified chitosan, a natural polymer obtained from the deacetylation of chitin, which is commonly found in the shells of crustaceans. The implications of applying chitosan in agriculture primarily involve regulating soil water and fertilizer conditions, thereby promoting more efficient crop growth and elevating agricultural sustainability, especially in regions with limited water availability.

Led by a team of researchers from Shandong Agricultural University, including Mingshang Liu, Jinxi Li, Bincheng Ren, Yan Liu, Zihan Liu, Tongtong Zhou, and Dongdong Cheng, the research details the optimal preparation conditions for the carboxymethyl chitosan-based fertilizer. These conditions include particular percentages and ratios of the chemical ingredients, such as MBA, KPS, AM to AA, CMC content, and UF, as well as specific reaction temperatures and times.

Results from the study show that the maximized water absorption rate of the optimized carboxymethyl chitosan, abbreviated as NC, reached an impressive 172.3 g/g. Moreover, the cumulative release of nitrogen over a 30-day span was 83.67%. When applied to sandy soil, the carboxymethyl chitosan greatly promoted seed germination and growth, demonstrating its broad application prospects in arid regions due to its exceptional water retention and nutrient release performance.

This comprehensive study not only showcases the feasibility of carboxymethyl chitosan as a medium for slow-release fertilizers but also underscores its potential to revolutionize agricultural practices in arid and semi-arid areas where water scarcity prevails. As it stands, current agricultural practices in these regions face challenges such as unpredictable rainfall, water-intensive irrigation methods, and the rapid depletion of water tables, among other irrigation-related issues. By creating a fertilizer that effectively retains moisture and delivers essential nutrients over a sustained period, there is potential to reduce the frequency of watering and to take a step forward in the struggle against drought and soil degradation.

The authors of the study declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in the paper. This ensures the integrity and impartiality of the research findings.

References

1. Liu, M., Li, J., Ren, B., Liu, Y., Liu, Z., Zhou, T., & Cheng, D. (2024). The water-retaining functional slow-release fertilizer modified by carboxymethyl chitosan. Carbohydrate Polymers, 328, 121744. https://doi.org/10.1016/j.carbpol.2023.121744

2. Zhao, Y., Wang, Y., Zhu, H., Zhang, Z., & Li, R. (2021). Advances in design and application of chitosan-based sustainable composites for water and fertilizer retention in agriculture. Environmental Science and Pollution Research, 28(30), 40479-40498. https://doi.org/10.1007/s11356-021-13951-z

3. El-Mohdy, H. L. A. (2020). Radiation synthesis of hydrogel, their applications in agriculture. Radiation Physics and Chemistry, 168, 108499. https://doi.org/10.1016/j.radphyschem.2019.108499

4. Azeem, B., Kushaari, K., Man, Z. B., Basit, A., & Thanh, T. H. (2014). Review on materials & methods to produce controlled release coated urea fertilizer. Journal of Controlled Release, 181, 11-21. https://doi.org/10.1016/j.jconrel.2014.02.020

5. Giroto, A. S., GuimarĂŁes, G. G. F., Foschini, M., Ribeiro, C., & Faria, R. T. (2017). Control of nutrient release by the chitosan coating of urea. Journal of Coatings Technology and Research, 14(1), 123-132. https://doi.org/10.1007/s11998-016-9827-6

Keywords

1. Slow-release fertilizer
2. Carboxymethyl chitosan
3. Superabsorbent resin
4. Soil water retention
5. Sustainable agriculture technology

With this new technology, farmers may have a powerful tool at their disposal to conserve water, reduce the wastage of fertilizers, and ultimately support global sustainability. For agriculture to adapt to the challenges of changing climates and growing populations, innovations like the water-retaining functional slow-release fertilizer could play a vital role in the future of farming.