Scalable SDS-templated CMCU@CaCl2 hydrogel with autonomous multisource hydration for atmospheric water harvesting and drought-resilient agriculture

Addressing water scarcity and agricultural sustainability under climate stress requires multifunctional materials with autonomous multisource hydration capable of harvesting moisture and supporting plant growth. Here, we report the development of a biodegradable, hydrogel composed of carboxymethyl cellulose (CMC), urea and CaCl 2 for integrated atmospheric water harvesting (AWH) and soil conditioning. Incorporation of sodium dodecyl sulfate (SDS) as a templating agent significantly enhanced the hydrogel's porosity and water uptake, as confirmed by SEM and BET surface analysis, which revealed increased pore volume, surface area, and morphological uniformity. The optimized CMCU@CaCl 2 hydrogel exhibited a high-water sorption capacity of 2.13 g/g at 90 % relative humidity and 25 °C, maintaining stable performance across 20–90 % RH. The condensed water met WHO purity standards, validating its suitability for agricultural applications. Agronomic trials demonstrated that the hydrogel extended maize plant survival from 7 to 20 days under drought conditions while maintaining comparable morphological traits to irrigated controls. Moreover, the hydrogel's ability to retain moisture and gradually release nitrogen improved soil water content and nutrient availability, enhancing drought resilience. This work introduces a cost-effective and scalable CMC-based hydrogel platform with strong potential for deployment in arid environments. Its dual function in autonomous multisource hydration and crop support offers a promising route toward sustainable agriculture and water management.