Foliar fertilization acts as a ubiquitous component of conventional crop production, which brings considerable economic and ecological costs. Due to droplets rebounding and splashing during spraying and rain erosion, low bioavailability of fertilizer results in severe environmental pollution. Contrary to conventional fertilizer formulations with polymers, surfactants, and organic reagents, a method of improving fertilizer bioavailability based on a biocompatible protein coating is presented herein. In this system, whey protein concentrate (WPC) can undergo amyloid-like aggregation after the reduction of its disulfide bond by the reducing agent tris(2-carboxyethyl) phosphine (TCEP). Such aggregation affords a fast formation of the optically transparent and colorless phase-transitioned WPC (PTW) coating at the solid/water interface, with robust interfacial adhesion stability. Upon packaging with fertilizers through electrostatic and hydrogen-bonding interactions, such reliable interfacial adhesion thereby facilitates the effective deposition of fertilizers on superhydrophobic and hydrophobic leaf surfaces, with excellent adhesion stability. Based on practical farmland test, this work demonstrates that the application of PTW can significantly boost the bioavailability of fertilizers and decrease at least 30% fertilizer use in large-scale crop planting. This innovative strategy has the great potential to offer a transformative step forward in managing fertilizer contamination and overuse in future agriculture.
Keywords: colloids; fertilizers; protein aggregation; superhydrophobic surfaces; surface/interfaces.
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