摘要:夜间增温幅度大于白天是气候变暖主要特征之一。夜间增温对水稻生产及CH₄和N₂O排放的影响备受关注。品种混栽可提高水稻产量，增强水稻植株抗性。增温或混栽单因子对稻田CH₄和N₂O排放影响已有报道，但二者耦合如何影响水稻生产及稻田CH₄和N₂O排放，尚不清楚。采用2因素随机区组设计，通过田间试验研究了夜间增温下品种混栽对水稻产量、CH₄和N₂O综合增温潜势和排放强度的影响。夜间增温设2水平，即对照（CK，control）和增温（NW，nighttime warming）；品种混栽设2水平，即混作（I，intercropping），单作（M，monocropping），混栽处理将主栽品种（超级稻南粳9108）与次栽品种（杂交稻深两优884）以3：1的比例种植。水稻生长期用铝箔反射膜覆盖水稻冠层进行被动式夜间增温试验（19：00-6：00）。结果表明，夜间增温或品种混栽均显著降低水稻植株分蘖数和生物量。品种混栽显著提高水稻产量，而夜间增温则显著降低产量。品种混栽可缓解夜间增温对水稻产量的抑制作用。夜间增温下品种混栽处理稻田CH₄累计排放量在分蘖期、拔节-孕穗期、抽穗-扬花期和灌浆-成熟期比单作对照分别高55.32%、45.89%、43.49和125.82%。夜间增温下品种混栽处理稻田N₂O累计排放量在分蘖期、拔节-孕穗期和抽穗-扬花期分别比单作对照高64.44%、46.26%和42.07%。研究认为，夜间增温下品种混栽显著提高稻田CH₄和N₂O排放通量和累积排放量，显著增加综合增温潜势（GWP）和排放强度（GHGI）。



Abstract:Asymmetric diurnal warming is one of the main characteristics of global climate change. The effects of nighttime warming on rice production, methane (CH₄) and nitrous oxide (N₂O) emissions in paddy field have received more attention. Intercropping can increase rice yield, and enhance rice resistance. Some reports have been available concerning nighttime warming or intercropping effects on CH₄ and N₂O emissions in rice fields, but it is still unclear regarding the effects of both coupling on the emissions in paddy field. We carried out a field experiment with a two-factor randomized block design to investigate the effect of intercropping on rice yield, CH₄ and N₂O global warming potential, and greenhouse gas emission intensity under nighttime warming. The experiment was performed at the Station of Agricultural Meteorology, Nanjing University of Information Science and Technology, Nanjing, China. The tested paddy soil was classified as Typic Stagnic Anthrosol. Warming was set at two levels- control and nighttime warming-and the degree of intercropping was set at two levels, i.e., intercropping and monocropping. Intercropping was achieved by transplanting at a ratio of 3:1 the main planting cultivar (super cv. Nanjing 9108) with the secondary planting cultivar (hybrid cv. Shenliangyou 884). During the rice-growing season, nighttime warming was achieved by covering the rice canopy with an aluminum foil reflective film at night (19:00-6:00). CH₄ emission was measured by the closed chamber method at 1-week intervals during the rice-growing period. The results showed that nighttime warming or intercropping significantly reduced tiller number and aboveground and root dry matter weight in rice. Intercropping significantly increased yield, while nighttime warming significantly reduced yield in rice. Intercropping could alleviate the inhibitory effect of nighttime warming on yield in rice. The CH₄ cumulative emission in the treatment with intercropping under nighttime warming was 55.32%、45.89%、43.49 and 125.82% higher than that monocropping at tillering stage, jointing-booting stage, heading-flowering stage, and filling stage. Under nighttime warming, N₂O cumulative emission in the treatment with intercropping at tillering stage, jointing-booting stage and heading-flowering stage was 64.44%、46.26%, and 42.07% higher than that monocropping. Intercropping significantly increased the fluxes and the cumulative emissions of CH₄ and N₂O and significantly increased the global warming potential and greenhouse gas emission intensity under nighttime warming.





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