Abstract. The shortage of water resources and the decline in soil organic matter (SOM) are important limiting factors affecting the improvement of rice productivity, while alternate wetting and drying (AWD) irrigation and rice straw return are considered favorable mitigation measures. However, its impact on rice yield and greenhouse gas (GHG) emissions, especially nitrous oxide (N₂O) emissions, needs to be further clarified, which is essential for the development of agronomic measures for water savings, soil fertilization and GHG reduction. Therefore, we explored the effects of mild AWD irrigation combined with rice straw return on N₂O emissions and rice yield through rice pot experiments. This study showed that N₂O emissions were mainly affected by urea application and irrigation methods, and urea application was the main reason. Compared with continuous flooding (CF) irrigation, mild AWD irrigation increased cumulative N₂O emissions, with an average increase of 28.8 %. In addition, adding rice straw to mild AWD irrigation further stimulated N₂O emissions. Compared with CF irrigation, mild AWD irrigation increased the yield-scaled N₂O emissions, and the addition of rice straw further promoted the yield-scaled N₂O emissions under mild AWD irrigation but reduced the global warming potential (GWP) by 62.9 %. Under the condition of urea application, compared with CF irrigation, mild AWD irrigation reduced nitrogen uptake by rice in the soil and rice aboveground biomass without reducing rice yield. Therefore, mild AWD irrigation combined with rice straw return is a promising agronomic measure to ensure rice yield, reduce the greenhouse effect and maintain or improve soil fertility.

中文翻译：

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温和干湿交替灌溉和稻草施用对水稻栽培N2O排放的影响

摘要。水资源短缺和土壤有机质（SOM）下降是影响水稻生产力提高的重要限制因素，而干湿交替（AWD）灌溉和稻草还田被认为是有利的缓解措施。然而，其对水稻产量和温室气体（GHG）排放，特别是一氧化二氮（N ₂ O）排放的影响需要进一步阐明，这对于制定节水、土壤施肥和减少温室气体的农艺措施至关重要。因此，我们通过水稻盆栽试验探讨了轻度AWD灌溉结合稻草还田对N ₂ O排放和水稻产量的影响。本研究表明，N ₂O排放主要受尿素施用和灌溉方式的影响，尿素施用是主要原因。与连续漫灌（CF）灌溉相比，轻度AWD灌溉增加了累积N ₂ O排放，平均增加了28.8%。此外，在轻度 AWD 灌溉中添加稻草进一步刺激了 N ₂ O 排放。与CF灌溉相比，轻度AWD灌溉增加了产量尺度的N ₂ O排放，稻草的添加进一步促进了产量尺度的N ₂轻度 AWD 灌溉下的 O2 排放，但将全球变暖潜能值 (GWP) 降低了 62.9%。在尿素施用条件下，与CF灌溉相比，轻度AWD灌溉减少了水稻对土壤中氮素的吸收和水稻地上生物量，而不降低水稻产量。因此，温和的AWD灌溉结合稻草还田是保证水稻产量、减少温室效应和保持或提高土壤肥力的一种很有前景的农艺措施。