Nitrous oxide emission from a transplanted rice field in alluvial soil as influenced by management of nitrogen fertiliser

We investigated nitrous oxide (N 2 O) emission from an irrigated rice field over two years to evaluate the management of nitrogenous fertiliser and its effect on reducing emissions. Four forms of nitrogenous fertilisers: NPK at the recommended application rate, starch–urea matrix ( SUM ) +  PK , neem‐coated urea +  PK and urea alone (urea without coating) were used. Gas samples were collected from the field at weekly intervals with the static chamber technique. N 2 O emissions from different treatments ranged from 11.58 to 215.81 N 2 O‐N  μ g/m 2 /h, and seasonal N 2 O emissions from 2.83 to 3.89 kg N 2 O‐N/ha. Compared with other fertilisers, N 2 O emissions were greatest after the application of the conventional NPK fertiliser. Moreover, SUM  +  PK reduced total N 2 O emissions by 22.33% ( P  < 0.05) compared with NPK during the rice‐growing period ( P  < 0.05). The results indicate a strong correlation between N 2 O emissions and soil organic carbon, nitrate, ammonium, above‐ and below‐ground plant biomass and photosynthesis ( P  < 0.05). The application of SUM  +  PK in rice fields is suitable as a means of reducing N 2 O emissions without affecting grain production.