Role of Nitrogen fixation in Carbon sequestration

Nitrogen fixation plays a critical role in enhancing carbon sequestration, particularly in terrestrial ecosystems where plant productivity and microbial processes are tightly linked to nitrogen availability. Biological nitrogen fixation (BNF), carried out by free-living and symbiotic microorganisms such as Rhizobium, Nitrobacter, Nitrosomonas, Frankia, and cyanobacteria, converts atmospheric nitrogen (N₂) into bioavailable forms, supporting plant growth in nitrogen-limited soils. Enhanced plant biomass from increased nitrogen input translates into greater carbon dioxide (CO₂) uptake through photosynthesis and more carbon allocated to root systems and soil organic matter. Legume-based systems, through their symbiotic nitrogen-fixing capacity, not only reduce dependency on synthetic fertilizers but also foster increased soil carbon stocks via root exudates and litter deposition. In grasslands, forests, and agroecosystems, the coupling of nitrogen fixation and carbon inputs can improve soil structure, microbial activity, and long-term carbon storage. Moreover, BNF can influence soil carbon dynamics by altering microbial decomposition rates and the stabilization of organic matter through nitrogen-rich compounds. However, the efficiency of this process depends on multiple factors including plant species, soil type, microbial community composition, and environmental conditions. Integrating nitrogen-fixing species into sustainable land management strategies—such as agroforestry, cover cropping, and reforestation—can significantly enhance carbon sequestration while restoring soil fertility. Understanding and leveraging the synergies between nitrogen fixation and carbon storage is therefore vital for climate change mitigation, soil health, and ecosystem resilience. Ongoing research into optimizing BNF in various ecosystems offers a promising avenue to maximize carbon sequestration benefits in the face of global environmental challenges.