Harnessing nitrogen fixing plants for a bio-solar nitrogen economy

: The fossil fuel–driven chemosynthesis of ammonia for nitrogen fertilizers is a major contributor to global greenhouse gas emissions, releasing approximately 1130 million metric tons (MMT) of CO 2 -equivalent annually. In addition, the extensive use of synthetic nitrogen fertilizers (≈108 MMT annually) results in substantial emissions of nitrous oxide (N 2 O), while nearly 50% of applied nitrogen is lost through leaching and runoff, leading to widespread nitrate pollution and ecosystem degradation. In contrast, solar-powered biological nitrogen fixation (BNF) by nitrogen-fixing plants offers a sustainable alternative that supports agricultural productivity and healthy ecosystem resilience. BNF by leguminous and non-leguminous plants plays a critical role in reducing dependence on synthetic nitrogen fertilizers. Legumes alone contribute an estimated ∼32-149kg.hm -2 of fixed nitrogen annually. Beyond legumes, associative, endosymbiotic, and endophytic nitrogen fixation in non-legume plants further expands the ecological and taxonomic scope of BNF. Nitrogen-enriched cropping systems, such as legume–cereal rotations, can reduce greenhouse gas emissions by up to 88%, increase soil organic carbon stocks by approximately 8%, enhance soil microbiome activity by 45%, and provide farmers with 15–25% more stable revenues. Advances in biotechnology offer new opportunities to improve nitrogen fixation efficiency and develop novel nitrogen-fixing crops, including cereals and perennial fruit trees. By integrating nature’s evolutionary solutions (N 2 -fixing plants) with modern biotechnology, agriculture can transition from a fossil fuel–based chemo-nitrogen economy to a solar-powered bio-nitrogen economy.