Straw return with chemical fertilizers is integral to improving soil quality and the sustainability of agricultural production. However, little is known about how straw return with chemical fertilizer application affects CO2 emissions and carbon pools from the perspective of nutrient stoichiometry. We conducted a 2‐year (2020–2021) field experiment in a wheat–maize rotation system in silty clay loam to study the effects of straw return and fertilizer application on CO2 emissions, soil carbon pools and yields by applying stoichiometry. A split‐plot experimental design was used (straw was main treatment, and fertilizer was the split‐plot treatment). The treatments were no straw return + no fertilizer (S0W), no straw return + mineral nitrogen fertilizer (S0N), no straw return + mineral nitrogen and phosphorus fertilizer (S0NP), straw return + no fertilizer (SW), straw return + mineral nitrogen fertilizer (SN) and straw return + mineral nitrogen and phosphorus fertilizer (SNP). The results indicated that, compared with S0W, the SNP treatment significantly increased soil organic carbon (SOC) storage by 17% and 13% in the 0–20 cm and 20–40 cm soil horizons, respectively. Additionally, compared with S0W, the SNP and SN treatments significantly increased the annual cumulative CO2 emissions by 85% and 41%, respectively. Furthermore, the SNP and SN treatments significantly increased the annual yield by 61% and 38%, respectively, compared with S0W. Our results indicated that straw and fertilizer inputs reduced the C:Nimbalance in the topsoil (0–20 cm), with fertilizer inputs showing a more pronounced effect. However, straw incorporation increased the C:Nimbalance in subsoil (20–40 cm). Redundancy analysis (RDA) and structural equation models (SEM) suggested that 0–20 cm carbon‐phosphorus ratio (C:P) and nitrogen‐phosphorus ratio (N:P) could be significant predictors of annual yield and CO2 emissions. In conclusion, straw and fertilizers enhanced soil nutrient effectiveness and reduced carbon mineralization in favour of SOC storage. However, the input of exogenous materials (straw and fertilizers) disrupted the soil ecological stoichiometric balance and stimulated microbial activity, leading to increased CO2 emissions. Overall, this study provides theoretical guidance and scientific support for the green development of agriculture.

中文翻译：

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化肥秸秆还田通过调节化学计量改善土壤碳库和 CO2 排放


使用化肥进行秸秆还田是改善土壤质量和农业生产可持续性不可或缺的一部分。然而，从养分化学计量学的角度来看，关于化肥施用秸秆还田如何影响 CO2 排放和碳库知之甚少。我们在粉质粘壤土中进行了为期 2 年 （2020-2021） 的小麦-玉米轮作系统田间试验，通过应用化学计量学研究秸秆还田和施肥对 CO2 排放、土壤碳库和产量的影响。采用分区实验设计（秸秆是主要处理，肥料是分区处理）。处理为无秸秆还田+无肥（S0W）、无秸秆还田+矿物氮肥（S0N）、无秸秆还田+矿物氮磷肥（S0NP）、秸秆还田+无肥（SW）、秸秆还田+无机氮肥（SN）和秸秆还田+矿物氮磷肥（SNP）。结果表明，与 S0W 相比，SNP 处理在 0—20 cm 和 20—40 cm 土壤层位中显著增加了 17% 和 13% 的土壤有机碳 （SOC） 储量。此外，与 S0W 相比，SNP 和 SN 处理分别显著增加了 85% 和 41% 的年累积 CO2 排放量。此外，与 S0W 相比，SNP 和 SN 处理分别显著提高了 61% 和 38% 的年产量。我们的结果表明，秸秆和肥料投入降低了表层土壤 （0–20 cm） 的 C：Nimbalance，其中肥料投入显示出更明显的效果。然而，秸秆掺入增加了底土 （20–40 cm） 中的 C：Nimbalance。 冗余分析 （RDA） 和结构方程模型 （SEM） 表明，0-20 cm 碳磷比 （C：P） 和氮磷比 （N：P） 可能是年产量和 CO2 排放量的重要预测因子。总之，秸秆和肥料提高了土壤养分有效性，减少了碳矿化，有利于土壤有机碳储存。然而，外源物质（秸秆和肥料）的输入破坏了土壤生态化学计量平衡并刺激了微生物活动，导致 CO2 排放增加。本研究为农业绿色发展提供了理论指导和科学支撑。