Nano-Modified Phosphate Fertilizers for Effective Nutrient Delivery and Eutrophication Management

Abstract Submission: Phosphorus from various sources, including fertilizers, is a primary contributor to eutrophication. The plant use efficiency (PUE) of phosphorus fertilizers is typically less than 20%, with most of the unused phosphorus ending up in water bodies. The authors have developed nano-modified rock phosphate (RP) fertilizers to increase PUE. The work focuses on delivering phosphorus (P) efficiently to plants in both acidic and alkaline soils, thereby minimizing runoff. Layer-by-layer biodegradable polymer deposition technique was used to coat nano-sized RP. The biopolymers include chitosan and hyperbranched organic acid. Batch studies carried out to investigate the release of phosphorus over a 60-day period showed that a chitosan coating on RP reduced P release by 45%. The subsequent coating with the hyperbranched organic acid facilitated a controlled release of phosphorus over time. Overall, the nano-modified rock phosphate (RP) fertilizers developed in this study demonstrated more efficient phosphorus release and a higher amount of plant-available phosphorus (580 mg/kg) compared to standard (unmodified) RP (200 mg/kg). Field-testing of the patented fertilizers is ongoing.

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