In recent decades, agricultural productivity has increased dramatically, largely driven by the widespread adoption of intensive practices introduced during the green revolution. While this progress has helped meet global food demand, it has also come with significant environmental consequences. To sustain a rapidly growing population, the use of fertilizers has risen sharply, now exceeding 55 million tons per year [1]. This trend is expected to continue, with projections suggesting further exponential growth in fertilizer demand, raising serious concerns about long-term sustainability, resource depletion, and environmental damage. In this context, the excessive and often uncontrolled application of fertilizers has led to a range of environmental issues, including soil degradation, water contamination, eutrophication of aquatic systems, and contributions to climate change [2]. At the same time, the worsening global water crisis is highlighting the urgent need to improve water efficiency in agriculture.

To address these challenges, superabsorbent polymers (SAPs), particularly potassium-based polyacrylates (SAP-K), have gained attention as promising materials due to their ability to retain large amounts of water and enhance soil moisture [3]. These materials are low-cost, non-toxic, environmentally safe, and do not contribute to soil salinization, making them well suited for sustainable agricultural applications [3].

In this work, SAPs-K were modified to serve a dual function: acting as nutrient-enriched slow-release fertilizers and enabling the recovery of water vapor from high-temperature emissions, such as industrial chimneys. To the best of our knowledge, although SAPs-K have been commercially available for many years, no previous studies have investigated this combination of functionalities.

In this study, commercial SAPs-K were modified using nutrient-rich precursors - such as starch, ethylenediamine, L-asparagine, and hydroxyapatite - to introduce key elements including nitrogen, calcium, and phosphorus. The modified materials were then tested for their ability to absorb water vapor at 160 °C, and the most promising formulations were further evaluated for nutrient release in soil. The results showed that nutrient enrichment significantly improved the polymers’ ability to absorb water vapor. To assess their practical potential in agriculture, nutrient release tests were carried out, demonstrating that the modified materials increased soil water retention by up to 40% and enabled a gradual release of nutrients into the soil.

In addition, a Life Cycle Assessment (LCA) was conducted to specifically evaluate the environmental impact associated with the chemical modifications applied to SAPs-K aimed at enhancing their nutrient content. This approach allowed for a clearer understanding of the trade-offs between improved agronomic performance and environmental sustainability, ensuring that the enhancement of nutrient release capabilities does not compromise the overall environmental profile of the material. Overall, these findings highlight the potential of nutrient-enriched SAPs-K as multifunctional materials for sustainable agriculture. By combining water vapor recovery with the controlled release of both water and nutrients, these systems offer a promising approach to tackling water scarcity and improving fertilizer efficiency. Their low cost, environmental compatibility, and circular design make them strong candidates for future agricultural innovation

References

1- M. A. Sutton, A. Bleeker, C. M. Howard, M. Bekunda, B. Grizzetti Probl. Agric. Econ. 2013, 3, 127.

2- C. Dordas, Conservation Agriculture, 1st ed., 2015, Cham, Switzerland, Springerp.

3- S. Behera, P. A. Mahanwar Polym. Plast. Technol. Mater. 2019, 59, 341.