Agriculture in the 21st century faces the dual challenges of increasing productivity while mitigating its impact on climate change. Nitrogen fertilizers are indispensable for increasing agricultural productivity, but hasten climate warming through greenhouse gas emissions. This study examined the effects of intercropping Cicer milkvetch (Astragalus cicer L.) with Smooth bromegrass (Bromus inermis Leyss.) and Ryegrass (Lolium perenne) at different nitrogen rates (300, 225, 150, and 75 kg ha-1) on hay yield, forage quality, and greenhouse gas emissions. The decrease in nitrogen fertilizer resulted in a linear decline in the yield and quality of monoculture grasses. However, milkvetch+bromegrass and milkvetch+ryegrass intercrops with 150 kg nitrogen ha-1 achieved highest hay yield (9.05-9.12 and 8.17-8.88 t ha-1), crude protein (1.39-1.43 and 1.18-1.23 t ha-1), and relative feed value yield (20.70-20.73 and 19.63-21.33 t ha-1) in 2021-2022, respectively. Legume-grass intercrops presented a good trade-off between environmental sustainability and yield benefits compared to monoculture pastures, indicated by lower greenhouse gas emissions, greenhouse gas intensity, and global warming potential. Milkvetch+bromegrass and milkvetch+ryegrass intercrops with 150 kg nitrogen ha-1 reduced cumulative nitrous oxide emissions by 59.11-62.92 % and 56.23-58.24 %, global warming potential by 59.83-64.02 % and 55.32-59.55 %, and greenhouse gas intensity based on hay yield by 70.96-78.47 % and 67.16-75.47 %, and based on crude protein yield by 83.14-88.12 % and 69.41-83.44 % compared to grass monocultures with nitrogen rate of 300 kg ha-1 in 2021 and 2022, respectively. Pasture fields acted as net methane sinks. Soil inorganic nitrogen and water contents were the primary regulating factors of greenhouse gas fluxes. Overall, legume-grass intercropping, specifically milkvetch+bromegrass with 150 kg nitrogen ha-1, represents a climatesustainable strategy for enhancing forage productivity in arid regions.