Nitrogen (N) fertilization improves crop growth and productivity, but can cause adverse environmental problems in particular nitrous oxide (N2O) emissions, requiring reasonable fertilization strategy for a better agroecosystem. Our goal was to understand how different N fertilizations influence greenhouse gas (GHG) emissions (CO2, CH4, and N2O) and global warming potential (GWP), soil properties, and productivity from lettuce (Lactuca sativa) cultivated fields [control (No fertilizer), urea ((NH2)2CO), ammonium sulfate ((NH4)2SO4), and compost (10 Mg ha -1)]. Inorganic N fertilizations significantly increased GWP as compared to the control, mainly increasing N2O emissions. However, CH4 and CO2 were not significantly different among all treatments, indicating N2O emissions were main contributors to be influenced by N fertilizations. Ammonium sulfate showed higher GWP than the urea. However, GWP was lowest in the control, but was not significantly different as compared to the compost. Lettuce yield was significantly enhanced by chemical N fertilizations, showing much greater biomass in ammonium sulfate than the urea. Lettuce yield with the compost was less than with chemical fertilizations, but significantly greater than control. GWP per productivity as an indicator for sustainability was lowest in compost treatment among all treatments mainly due to reduced GHG emissions by less mineralization. Conclusively, compost application could be a sustainable way to mitigate GHG emissions, maintaining soil quality and productivity in upland soils.

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