| Summary: | Nitrogen (N) fertilization is one of the most effective practices to increase productivity, and has therefore had a fast global increase. Consequently, the effects of the application of N fertilizer on emissions of N<sub>2</sub>O have been widely studied, but the effect of rice planting on N<sub>2</sub>O emission was not adequately quantified. To evaluate the effect of rice cultivation on N<sub>2</sub>O emissions, different levels of N were applied in a typical temperate rice field, and the N<sub>2</sub>O fluxes were compared in rice-planted and non-planted soils. Seasonal N<sub>2</sub>O fluxes responded differently with respect to N fertilization in the two different soil conditions. In non-planted soils, seasonal N<sub>2</sub>O fluxes ranged within 0.31–0.34 kg N<sub>2</sub>O ha<sup>−1</sup> under 0 kg N ha<sup>−1</sup> fertilization, and significantly increased by increasing N fertilization rates, with an average rate of 0.0024 kg N<sub>2</sub>O kg<sup>−1</sup> N for 3 years. In rice-planted soils, seasonal N<sub>2</sub>O fluxes were also increased by N fertilization but showed large negative N<sub>2</sub>O fluxes, irrespective of the N fertilization level. This study confirms that the rice reacted as a reducer of N<sub>2</sub>O emissions, not an emission source, in paddy fields, suggesting that N<sub>2</sub>O fluxes should be estimated by the static chamber planted with rice to obtain a more precise field environment. The differences of N<sub>2</sub>O fluxes between the rice-planted and non-planted soils might have been caused by the rice plant’s rhizospheric activities, which may have influenced the N<sub>2</sub>O consumption potential in the rice plants’ rhizosphere. The N<sub>2</sub>O consumption potential was significantly increased with increasing N fertilization rates and was highly correlated with rice biomass yields. Therefore, the decrease in N<sub>2</sub>O fluxes by N fertilization in rice-planted soils might have been caused by a decreasing denitrification potential in paddy soils.
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