Metal-Phenolic Complexation Governs Soil Mineral Crystallinity to Enhance Crop Growth

Plants release polyphenols into soil under stress, yet their role in regulating soil mineral structure and nutrient availability is unclear. Herein, tannic acid (TA), a representative plant-derived polyphenol, is used to first demonstrate the role of natural mineral particle restructuring in soil to control nutrient availability-a phenomenon that is facilitated through the formation of amorphous metal-phenolic complexes. From these findings, a coordination-driven assembly strategy is devised to engineer minerals with tunable crystallinity via coprecipitation of TA and minerals (calcium phosphate and struvite). These nature-inspired hybrid minerals exhibit reduced crystallinity (up to 46% relative to the control minerals) depending on the amount of TA incorporated (up to 17%), enabling tunable disassembly behavior. The TA-loaded minerals exhibit enhanced nutrient release and polyphenol codelivery under biologically relevant conditions, primarily driven by TA-induced destabilization of the mineral lattice. Pot experiments reveal increased biomass production (up to 2.5-fold) using the TA-loaded minerals, largely due to enhanced nutrient bioavailability, stimulatory effects of TA on crop growth, and enrichment of crop-beneficial microbes. The findings unveil the role of plant polyphenols in regulating soil mineral dynamics and demonstrate a strategy for designing fertilizers that leverage plant-soil-microbe feedback mechanisms.