Understanding farmland ecosystem processes such as straw decomposition under nitrogen fertilization is critical for predicting carbon and nitrogen cycles. Nitrogen fertilization significantly affects soil and straw quality, which may significantly affect straw decomposition; however, comprehensive studies considering both factors are lacking. To evaluate the decomposability of crop residues under nitrogen fertilization, we conducted three subexperiments involving straw decomposition in situ, decomposition of the same straw in soils with different nitrogen fertilization regimes and decomposition of different straw types in the same soil with nitrogen fertilization and investigated the changes in soil respiration and wheat straw physicochemical properties. Nitrogen fertilization promoted straw decomposition: 180 and 360 kg N ha⁻¹ year⁻¹ increased the weight loss rate by 9.95% and 11.15%, respectively, but the difference between the two was not significant. The carbon emissions under 360 kg N ha⁻¹ year⁻¹ were significantly higher than those under 180 kg N ha⁻¹ year⁻¹. Straw chemical characteristics exhibited different sensitivities to nitrogen fertilization; hemicellulose responded positively to 180 kg N ha⁻¹ year⁻¹, while carbon and cellulose had obvious responses to only 360 kg N ha⁻¹ year⁻¹. The soil temperature, soil moisture, straw nitrogen content, and straw C/N ratio were the main factors affecting decomposition. Excessive nitrogen fails to promote nutrient return during straw decomposition and may also increase carbon emissions from farmland soil and aggravate the greenhouse effect. This study provides a theoretical basis for understanding nutrient cycling in farmland ecosystems under reasonable fertilization regimes and for improving farmland soil quality and nitrogen fertilization.

了解农田生态系统过程，如施氮肥下的秸秆分解，对于预测碳和氮循环至关重要。施氮显着影响土壤和秸秆质量，可能显着影响秸秆分解；然而，缺乏考虑到这两个因素的综合研究。为评价施氮条件下作物秸秆的分解能力，我们进行了秸秆原位分解、同种秸秆在不同施氮方式土壤中分解、同一土壤中不同类型秸秆在施氮条件下分解的三个子试验，研究了其变化情况。土壤呼吸和小麦秸秆理化性质的影响。施氮促进秸秆分解：180 和 360 kg N ha^-1 年^-1体重减轻率分别增加了9.95%和11.15%，但两者差异不显着。360 kg N ha ^-1  year ^-1以下的碳排放显着高于180 kg N ha ^-1  year ^-1以下的碳排放。秸秆化学特性对施氮的敏感性不同；半纤维素对 180 kg N ha ^-1  year ^{-1 有}积极响应，而碳和纤维素仅对 360 kg N ha ^-1  year ^-1有明显响应. 土壤温度、土壤水分、秸秆氮含量和秸秆碳氮比是影响分解的主要因素。过量的氮不能促进秸秆分解过程中的养分回流，还可能增加农田土壤的碳排放，加剧温室效应。本研究为了解合理施肥制度下农田生态系统养分循环、改善农田土壤质量和施氮提供理论依据。