文摘
We investigated nitrous oxide (N<sub>2sub>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<sub>2sub>O emissions from different treatments ranged from 11.58 to 215.81 N<sub>2sub>O-N μg/m<sup>2sup>/h, and seasonal N<sub>2sub>O emissions from 2.83 to 3.89 kg N<sub>2sub>O-N/ha. Compared with other fertilisers, N<sub>2sub>O emissions were greatest after the application of the conventional NPK fertiliser. Moreover, SUM + PK reduced total N<sub>2sub>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<sub>2sub>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<sub>2sub>O emissions without affecting grain production.