Syed Burhan Geelani, Arindam Saraf, Prasanta Das
This review integrates biogeochemical, microbial regulation, and climatic control pathways to synthesize fertilizer-driven greenhouse gas (GHG) emissions. The potential of new fertilizer technologies, such as bio-based amendments, enhanced-efficiency fertilizers, inhibitors, and nanofertilizers, to increase nitrogen use efficiency (NUE) and lower emissions is assessed critically. Their performance is still site-dependent, though. The review highlights key trade-offs, demonstrating that increasing nitrogen input beyond optimal levels reduces NUE while disproportionately increasing emissions. Enzyme-mediated mechanisms controlling N 2 O, CH 4 and CO 2 fluxes are studied in conjunction with core activities such as nitrification, denitrification, methanogenesis, and respiration. A systems-level approach is used to explain how nitrogen inputs, soil characteristics, microbial dynamics, and environmental factors interact to produce emissions and feedback amplification under climate change. To achieve sustainable intensification, the study emphasizes the necessity of integrated, site-specific nutrient management and system-level optimization. Croplands are a significant source of GHG emissions, particularly N 2 O, due to agricultural intensification aimed at meeting growing food demand, which has increased reliance on nitrogen fertilizers. Despite increased production, conventional fertilizer methods remain ineffective due to high nutrient losses, low NUE, and detrimental environmental effects. Fertilizer management is a crucial intervention point within the framework of climate-smart agriculture (CSA) for addressing these issues.