Development of a Foliar Synergist Based on Radiation-Synthesized Potassium Polyacrylate for Rice Yield Enhancement

Stable rice production is critical for ensuring national food security and agricultural sustainability. Climate change is increasing the demand for efficient crop management strategies to maintain rice production. Foliar fertilization enables rapid nutrient supplementation by directly delivering nutrients to aboveground tissues while avoiding soil-related limitations. However, most foliar formulations are primarily designed for rapid nutrient delivery and have limited capacity to prolong water retention and nutrient availability on leaf surfaces after application. Hydrogels possess excellent water-retention and nutrient-delivery capabilities, but their intrinsic crosslinked networks limit water solubility and foliar suitability. Inspired by these characteristics, a sprayable polymer-based formulation was designed to combine hydrogel-like moisture preservation with foliar application compatibility. In this study, a foliar moisture-preserving synergist (FMPS) was developed using radiation-synthesized potassium polyacrylate as the polymer matrix, with urea and glucose incorporated as nitrogen and carbon sources, respectively. Structural characterization revealed morphological changes after incorporation of urea and glucose into PAA-K, while Fourier transform infrared spectroscopy suggested their incorporation and possible intermolecular interactions. Under standard growth conditions, FMPS increased the effective panicle number, filled grain number, and seed-setting rate by 29.3%, 18.4%, and 4.0%, respectively, resulting in significantly improved rice yield. These findings demonstrate the potential of FMPS as a hydrogel-inspired foliar formulation for enhancing rice productivity.