Active Water Cluster Reconfiguration Enables Seawater‐Potentiated Solar Evaporation for Agricultural Irrigation

Solar‐driven interfacial evaporation offers a sustainable route to alleviating global agricultural water scarcity, yet intrinsic energetic barriers at the gas–liquid interface limit its practical efficiency. Here, we report an electrospun nonwoven nanofibrous hydrogel fabric that combines textile‐like flexibility in the dry state with hydrogel functionality upon hydration. By synergizing the nanoscale interfacial compartmentalization of the fabric architecture with the molecular‐level regulation of functional groups, this material effectively disrupts long‐range cooperative hydrogen‐bonding networks, transforming bulk‐like water into less‐associated, more volatile water states. Crucially, we reveal a counterintuitive seawater‐induced activation mechanism, in which sodium ions trigger an ion‐exchange process that expands the polymer network and exposes hidden active sites. This dynamic activation delivers an exceptional salt‐enhanced evaporation rate of 2.92 kg m −2 h −1 for a 2D planar evaporator in natural seawater under 1 sun illumination. Validated through large‐area fabrication and winter field trials for greenhouse crop irrigation, this scalable architecture provides a robust, decentralized strategy for global agricultural water security.