Straw returning not only improves carbon (C) and nitrogen (N) pools but also increases soil nitrous oxide (N₂O) emissions, which poses a threat to the sustainable development of agriculture. To investigate the effect of straw return combined with nitrogen fertilizer on labile C and N pools in the soil and short-term response to soil N₂O emissions in wheat–maize rotation system. The consecutive field experiment was conducted from 2019 to 2021. Single factor randomized block design was used in the experiment design, with no straw returning and no fertilizer (CK), no straw returning and nitrogen fertilizer (S₀N) and straw returning combined with nitrogen fertilizer (SN). The results indicated that the SN and S₀N treatments significantly (p < .05) increased N₂O emissions by 170.45% (2.43 kg N ha⁻¹ year⁻¹) and 119.5% (1.70 kg N ha⁻¹ year⁻¹), soil organic carbon (SOC) by 17.23% and 14.50% and soil total nitrogen (STN) by 58.50% and 31.50% respectively. In the 2020–2021 growing season, The soil microbial biomass carbon (SMBC) content of the SN and S₀N treatments were higher than those of CK in the winter wheat seedling, winter wheat jointing, winter wheat booting, summer maize seedling and summer maize bell-mouth stages. The structural equation model (SEM) indicated that C:N and NO₃⁻-N were the major drivers that increased soil N₂O emissions, but SMBN was the main driver that decreased soil N₂O emissions. The SN and S₀N treatments significantly increased soil N₂O emissions by increasing the NO₃⁻-N content. However, compared with the CK and S₀N treatments, the SN treatment mitigated soil N₂O emissions by increasing the SMBN content. More importantly, compared with CK treatment, SN treatment increased annual yield by 48.41% and 34.52%, the SN treatment could effectively improve the soil C and N pools. Therefore, straw return combined with nitrogen fertilizer (SN) may be the best choice of the treatments tested for reducing greenhouse gas emissions and achieving green and sustainable development.

中文翻译：

---

秸秆还田结合氮肥如何驱动小麦-玉米轮作系统N2O排放

秸秆还田不仅改善了碳（C）和氮（N）库，还增加了土壤一氧化二氮（N ₂ O）排放，对农业可持续发展构成威胁。_{探讨秸秆还田结合氮肥对小麦-玉米轮作体系土壤不稳定碳氮库的影响及对土壤N 2} O排放的短期响应。2019年至2021年进行连续田间试验。试验设计采用单因素随机区组设计，不还田不施肥（CK）、不还田施氮肥（S ₀ N）和秸秆还田结合施氮。氮肥（SN）。结果表明，SN 和 S ₀ N 处理显着 ( p  < .05) 将 N ₂ O 排放量增加了 170.45%（2.43 kg N ha ^-1 年^-1）和 119.5%（1.70 kg N ha ^-1 年^{-1 ）}）、土壤有机碳（SOC）分别减少17.23%和14.50%，土壤全氮（STN）分别减少58.50%和31.50%。2020-2021年生长季,冬小麦苗期、冬小麦拔节期、冬小麦孕穗期、夏玉米苗期和夏季土壤微生物量碳(SMBC)含量SN和S ₀ N处理均高于CK。玉米喇叭口阶段。结构方程模型(SEM)表明，C:N和NO ₃ ^{− -N是增加土壤N} ₂ O排放的主要驱动因素，而SMBN是减少土壤N ₂ O排放的主要驱动因素。SN和S ₀ N处理通过增加NO ₃ ^{− -N含量显着增加了土壤N} ₂ O排放。然而，与CK和S ₀ N处理相比，SN处理通过增加SMBN含量来减少土壤N _{2 O排放。}更重要的是,与CK处理相比,SN处理年产量分别提高了48.41%和34.52%,SN处理能有效改善土壤碳、氮库。因此，秸秆还田结合氮肥（SN）可能是减少温室气体排放、实现绿色可持续发展的最佳处理方式。