Upcycling trace amounts of biomass waste into flash graphene can boost crop yields by more than a quarter and offer climate benefits

Global food security faces immense pressure from population growth and climate change, demanding sustainable agricultural intensification. While biochar offers promise for soil enhancement and carbon sequestration, its large-scale application requires significant biomass feedstock and energy-intensive production, raising economic and carbon footprint concerns. Nano-enabled foliar feeding is gaining momentum, but practical, eco-efficient field use from lab to farm remains challenging. Bridging this gap is essential for realizing nano-enabled agriculture without exacerbating environmental burdens. Here, we demonstrate on-site conversion of ecologically safe flash graphene via flash joule heating. Spraying 18 g/hectare of this graphene, produced from 75 g (<0.001%) of crop residues per hectare, on multi-crops over two seasons increased yields by 9.1%–27.3% through enhanced photosynthesis and alleviated oxidative stress. Compared to biochar, this approach reduces farmers' inputs by 86%–91% and lowers life-cycle carbon emissions by up to 10,000-fold. We offered a self-sufficient, scalable, and climate-smart circular foliar feeding pathway to advance food security sustainably.