Crop straw incorporation alleviates overall fertilizer-N losses and mitigates N2O emissions per unit applied N from intensively farmed soils: An in situ 15N tracing study

• Published in: The Science of the total environment 2021-04, Vol.764, p.142884, Article 142884
• Main Authors: Xu, Cong, Han, Xiao, Zhuge, Yuping, Xiao, Guangmin, Ni, Bang, Xu, Xiuchun, Meng, Fanqiao
• Format: Article
• Language: English
• Subjects: 15N tracing; Intensive farming; Nitrogen fertilization; Nitrogen loss; Nitrous oxide; Straw incorporation
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2020.142884

A thorough elucidation of the coupled effects of N fertilization and straw incorporation on N2O emissions and N losses is crucial for alleviating negative environmental impacts in intensively farmed regions. Here, we conducted an in situ 15N tracing experiment to assess the source of N2O emissions and fate of fertilizer-N in soil intensively farmed with summer maize (Zea mays L.). Four treatments, i.e., no N fertilization and no straw incorporation (N0S0), straw incorporation only (N0S1), N fertilization only (N1S0), and N fertilization plus straw incorporation (N1S1), were established in the study. Compared with straw removal, straw incorporation increased the seasonal N2O emissions by 22.3% but reduced the N2O emissions per unit of applied N by 6.22% (P > 0.05). The emission of fertilizer-derived N2O occurred mainly in the 13–17 days after fertilization; thereafter, the ratio of fertilizer-derived N2O fluxes would be less than 5%. N fertilization significantly stimulated non-fertilizer-derived N2O emissions and soil CO2 fluxes, especially when straw was incorporated (P