Biodegradable Polymer Nanocomposites Provide Effective Delivery and Reduce Phosphorus Loss during Plant Growth

Although phosphorus (P) is an essential element, its availability to plants is often limited, and P-containing fertilizers must be supplemented to stimulate plant performance. However, the inefficiencies and negative environmental impacts associated with current nutrient delivery strategies have motivated interest in nanotechnology-enabled agriculture. Here, we synthesized biodegradable polymer nanocomposites (PNCs) containing polyhydroxyalkanoate (PHA) and calcium phosphate nanoparticles (Ca-P-NPs) and assessed their efficacy as a P-delivery vehicle, compared to a conventional P source (CaHPO4), using tomato as a test plant. The effectiveness of PHA-Ca-P PNCs was assessed by measuring plant biomass, fruit yield and quality, tissue elemental and chlorophyll content, and enzymatic biomarkers. Phosphorus in the leachate was used as a surrogate for runoff. PHA-Ca-P PNCs biodegraded as a result of microbial activity in the soil, controlling the release of P during the initial stages of plant growth. PHA-Ca-P PNCs supported plant performance comparably to the conventional P source, while significantly reducing the P loss from the soil by over 80%. Given the negative consequences of eutrophication driven by P-rich agricultural runoff, this significant reduction in lost P has broad implications. Our studies also highlight the need to improve the efficiency of P uptake by plants from exogenous P sources. Collectively, these findings demonstrate the significant potential of biodegradable PNCs as a nutrient delivery platform to simultaneously enhance crop productivity and reduce the negative impacts of agriculture on the environment.