The combined effects of nitrogen (N) fertilizers and straw incorporation (SI) on GHG emissions, crop yields, and net ecosystem carbon budget (NECB) in summer maize-winter wheat rotation systems are still uncertain. We conducted a two-year field experiment to evaluate the effects of SI combined with different N fertilization practices on soil NO emissions, ecosystem respiration (Re), NECB, grain yields, net global warming potential (NGWP), and greenhouse gas intensity (GHGI). In total, five treatments were considered, namely conventional urea-N application (FP), optimal urea-N fertilizer (OPT) with and without SI (S+OPT and OPT), and enhanced-efficiency N fertilizers (equivalent to OPT) with and without SI (S+EENF and EENF). The results showed significantly decreased average annual NO emissions under the OPT and EENF treatments by 22.70 and 51.35% ( < 0.05), respectively, compared with that under the FP treatment. However, no significant differences in the annual Re emissions, NECB values, and crop yields were observed between the N fertilizer treatments ( > 0.05). The SI significantly increased the average annual NO emissions, annual Re emissions, and annual grain yields by 36.01, 27.94, and 11.54% ( < 0.05), respectively compared to no-straw treatments. The annual NECB values under the SI and no-straw treatments ranged from 1.19 to 1.94 t C ha yr and −1.89 to −1.19 t C ha yr, respectively. The lower NGWP and GHGI values were observed in the S+EENF plots. The results suggest that the practice of enhanced-efficiency N fertilizers coupled with SI could improve crop yields and reduce NGWP and GHGI values in summer maize-winter wheat rotation systems.

中文翻译：

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强化氮肥结合秸秆还田可以降低夏玉米-冬小麦轮作系统中的全球变暖潜力，同时提高碳固存量

夏玉米-冬小麦轮作系统中氮（N）肥和秸秆还田（SI）对温室气体排放、作物产量和净生态系统碳预算（NECB）的综合影响仍不确定。我们进行了为期两年的田间实验，评估 SI 结合不同施氮肥实践对土壤 N2O 排放、生态系统呼吸 (Re)、NECB、粮食产量、净全球变暖潜势 (NGWP) 和温室气体强度 (GHGI) 的影响）。总共考虑了五种处理，即常规尿素氮施用（FP）、添加和不添加SI的最佳尿素氮肥（OPT）（S+OPT和OPT）以及添加高效氮肥（相当于OPT）。且没有 SI（S+EENF 和 EENF）。结果表明，与 FP 处理相比，OPT 和 EENF 处理下的年平均 NO 排放量分别显着降低了 22.70% 和 51.35%（ < 0.05）。然而，氮肥处理之间的年铼排放量、NECB 值和作物产量没有观察到显着差异（> 0.05）。与无秸秆处理相比，SI 显着增加了年平均 NO 排放量、年 Re 排放量和年粮食产量，分别增加了 36.01、27.94 和 11.54%（ < 0.05）。SI和无秸秆处理下的年NECB值分别为1.19至1.94吨查年和-1.89至-1.19吨查年。在 S+EENF 图中观察到较低的 NGWP 和 GHGI 值。结果表明，高效氮肥与 SI 的结合可以提高夏玉米-冬小麦轮作系统中的作物产量并降低 NGWP 和 GHGI 值。