Journal of Integrative Agriculture ›› 2026, Vol. 25 ›› Issue (9): 3868-3881.DOI: 10.1016/j.jia.2025.12.046

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秸秆覆盖农田肥料氮回收与土壤有机碳稳定过程和组分构成的关系：基于15N示踪及13C自然丰度法分析

  

  • 收稿日期:2025-07-31 修回日期:2025-12-26 接受日期:2025-11-11 出版日期:2026-09-20 发布日期:2026-08-11

Fertilizer-N recovery links to SOC stabilization and fractionation in straw-mulched soil: Insights from 15N-tracing and 13C natural abundance

Cong Xu1, 3, 4, Ziqi Yang1, 4, Jing Wang2, Roland Bol5, 6, Weijie Li1, 3, Cheng Ji1, 4, Jie Yuan1, Lei Wang1, Dong Liang1, Hanshen Zhu1, 4, Jidong Wang1, 3, 4#, Yongchun Zhang1, 3, Yuchun Ai1   

  1. 1 National Agricultural Experimental Station for Agricultural Environment, Luhe/Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China

    2 Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China

    3 College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China

    4 School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China

    5 Institute of Bio- and Geosciences, Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Jülich 52425, Germany

    6 School of Natural Sciences, Bangor University, Bangor, Gwynedd, LL57 2UW, United Kingdom

  • Received:2025-07-31 Revised:2025-12-26 Accepted:2025-11-11 Online:2026-09-20 Published:2026-08-11
  • About author:Cong Xu, E-mail: cxu@jaas.ac.cn; #Correspondence Jidong Wang, E-mail: Jidongwang@jaas.ac.cn
  • Supported by:
    This work was supported by grants from the National Key R&D Program of China (2023YFD1901102-04), the National Natural Science Foundation of China (42477314, 42377338, and 42577335), the Basic Research Program of Jiangsu, China (BK20230076), the Jiangsu Agriculture Science and Technology Innovation Fund, China (CX(23)1019), the Key Research and Development Project of Jiangsu Province, China (BE2021378), and the China Agriculture Research System (CARS-10-Sweetpotato).

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摘要：

秸秆覆盖还田是消减集约化农田中肥料氮损失的重要途径。然而，覆盖还田土壤中有机碳（SOC）如何在团聚体和剖面尺度上调控肥料氮去向仍不明确。本研究在为期四年的田间定位试验中设置微区，结合15N示踪和13C自然丰度法，评估秸秆覆盖土壤中肥料氮的去向及其与SOC组分和稳定化过程的关系。试验共设置三个处理，分别为（i）常规施氮（FN）、（ii）减量施氮（RN）和（iii）减量施氮配合秸秆覆盖（RS）。结果显示，与FN相比，RN处理下的作物产量显著降低，而RS处理则在保持与FN相当产量的同时，实现肥料氮回收率提升7.71%（P<0.05）。在团聚体尺度上，＞2 mm及＜0.053 mm粒径中的δ13C分馏值与肥料氮含量呈显著正相关，表明氮素固持与SOC稳定化过程紧密关联；与RN相比，RS处理下SOC向＜0.053 mm团聚体的转化概率提高了2−3.4倍，同时团聚体结合的肥料氮含量增加了1.4倍。在剖面尺度上，不同SOC组分对肥料氮的分布具有差异化调控作用，表现为稳定性SOC与肥料氮含量呈正相关，而可溶性有机碳呈负相关，但后者提高了植株对肥料氮的利用率；相较于RN处理，RS处理显著增加了24%的SOC储量，减少了37%的NO₃⁻-N累积，并提升了36%的微生物氮固持量（P<0.05）。通过以上分析可知，秸秆覆盖可通过介导SOC组分、稳定化过程及微生物氮利用，有效提高氮素回收效率。研究结果有望为深入理解土壤SOC与氮素间的相互作用、优化土壤碳氮管理策略提供依据。

Abstract:

While straw mulching has the potential to reduce fertilizer-nitrogen (N) losses in intensively managed cropland, how soil organic carbon (SOC) regulates this fate of fertilizer-N at soil aggregate or profile scales remains unresolved.  Here, micro-plots were nested within a four-year field experiment to assess fertilizer-N fates and their linkages with SOC fractions and stabilization processes via 15N-tracing and 13C natural abundance analyses.  Three treatments were included: (i) conventional N application (FN), (ii) reduced N application (RN), and (iii) reduced N with straw mulching (RS).  While RN reduced crop yields compared to FN, RS achieved comparable yields and 7.71% higher N recovery efficiency (P<0.05).  The δ13C fractionation between aggregates and bulk soil was significantly positively correlated with the fertilizer-N content in the >2 mm and <0.053 mm fractions, indicating that N retention was coupled with SOC stabilization processes.  Compared with RN, RS resulted in a 2−3.4 times greater SOC conversion probability into the <0.053 mm fraction and a 1.4 times higher aggregate-associated fertilizer-N content.  SOC fractions differentially regulated the profile distribution of fertilizer-N, with nonlabile organic carbon (C) correlated positively, while dissolved organic C correlated negatively but increased plant N recovery.  Compared with RN, RS increased the SOC stock by 24%, reduced NO3−-N accumulation by 37%, and immobilized 36% more N into the microbial biomass (P<0.05).  Our findings demonstrate that straw mulching increases N recovery by mediating SOC fractionation, stabilization, and microbial N immobilization.  These results provide new insights into SOC–N interactions that could aid in the development of optimal soil C and N management strategies.

Key words: fertilizer-nitrogen fate , soil aggregate , soil organic carbon flow , 15N , 13C