Closing the gap between climate regulation and food security with nano iron oxides

Rice production poses one of the most important dilemmas between climate regulation and food security. While fertilization often results in a higher yield, it is also accompanied by more greenhouse gas (GHG) emissions. For this dilemma, the final consideration usually depends on the trade-offs to mitigate on-going climate change while supporting a continuously growing global population. Here we conducted a 4-year field experiment to evaluate the capacity of iron oxide nanoparticles (FeONPs) at 6.3 kg ha−1 yr−1 as the basal fertilizer to close the gap of such trade-offs. Compared with urea fertilization, FeONPs can mitigate climate change by reducing 50% of methane (CH4) and nitrous oxide (N2O) emissions while supporting significant soil carbon sequestration by 7.4% in the fourth year. Moreover, through reductions in ammonia volatilization and the entrapment of nitrogen in nanoparticles, FeONPs improve the retention of soil nitrogen nutrients, leading to an increase in food production of up to 25%. Our results show that FeONPs effects became more and more prominent throughout a continuous 4-year application. Together, our study revealed FeONPs as a next-generation fertilizer with great potential to solve the dilemma of meeting food security demand while complying with climate regulation. Rice is a staple crop for much of the world's population, but its production can be a major source of greenhouse gas emissions. Supplemental nano iron oxides application can halve these emissions while boosting crop yield.