Journal of Integrative Agriculture ›› 2025, Vol. 24 ›› Issue (10): 4063-4077.DOI: 10.1016/j.jia.2025.04.009

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长期秸秆还田下水稻—土壤系统中光合碳和外源氮的转运与分配的定量评估：一项13C 和15N同位素标记试验

  

  • 收稿日期:2024-11-08 修回日期:2025-04-04 接受日期:2025-03-11 出版日期:2025-10-20 发布日期:2025-09-24

Quantitative assessment of the transport and distribution of  photosynthetic carbon and exogenous nitrogen in a rice–soil system under long-term straw return: An isotope trial using 13C and 15N labelling

Shiqi Yang1*, Liming Chen2*, Yifan Tang1, Xueming Tan1, Yongjun Zeng1, Xiaohua Pan1, Yanhua Zeng1#   

  1. 1 Jiangxi Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education/Jiangxi Agricultural University, Nanchang 330045, China

    2 Jiangxi Key Laboratory of Plant Resources and Biodiversity, Jingdezhen University, Jingdezhen 333400, China

  • Received:2024-11-08 Revised:2025-04-04 Accepted:2025-03-11 Online:2025-10-20 Published:2025-09-24
  • About author:Shiqi Yang, E-mail: ysq19990720@163.com; Liming Chen, E-mail: 13657987055@163.com; #Correspondence Yanhua Zeng, E-mail: zyh74049501@163.com * These authors contributed equally to this study.
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (32160503), the Earmarked Fund for Jiangxi Agriculture Research System, China (JXARS-01), and the National Key R&D Program of China (2023YFD2301303).  

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摘要：

秸秆还田在提高碳固存和氮吸收方面已表现出显著潜力，同时还能促进植物生产力。然而，在秸秆还田条件下，水稻植株—土壤系统中光合碳以及外源氮的具体转运和分布情况仍不清楚。基于此，我们在双季稻系统中进行了一项长期秸秆还田定位试验，设置秸秆移除（F）、秸秆焚烧还田（SBR）和秸秆还田（SR）处理，以使用13C脉冲和15N同位素示踪技术研究碳固存和外源氮吸收。结果表明，在水稻植物—土壤系统中，与SBR和F处理相比，SR显著提高了土壤13C丰度，增幅为24.4%—25.4%，地上部植物中13C积累量（18.4%—35.8%），以及穗中15N的积累量（12.8%—34.3%）。这些变化增加了植株—土壤系统中总有机碳的含量以及水稻籽粒产量。SR显著提高了光合碳向土壤中转移，增幅达9.8%。对于水稻器官而言，与SBR相比，SR在叶片和茎中表现出更高的光合碳分布，但在穗中分布较低。说明秸秆还田有利于将光合碳固定到土壤中；相反，在15N分布中观察到了相反的趋势。此外，SR增加了对肥料尿素和土壤氮源中氮的吸收，将氮回收率提高了9.2%—12.5%，并降低了氮素残留。相关性分析表明，SR 提高了叶片和根部13C的积累量，同时降低了所有水稻器官中15N的丰度，从而增加了水稻的产量。 偏最小二乘法路径模型表明，SR 下水稻产量的增加主要与水稻—土壤系统中13C积累量有关。研究结果表明，长期秸秆还田有利于增加水稻植物—土壤系统中光合碳和外源氮的固存，特别是氮素利用效率，从而提高水稻和土壤的生产力。

Abstract:

Straw return has demonstrated significant potential for enhancing carbon (C) sequestration and nitrogen (N) uptake while concurrently promoting plant productivity.  However, the specific transport and distribution of C produced by photosynthesis and exogenous N within the rice plant–soil system under straw return remains unclear.  A long-term straw return pot trial experiment was conducted in a double cropping rice system, incorporating treatments of inorganic fertilizer application with straw removal (F), straw burning and ash return with reducing inorganic fertilizers (SBR), and straw return with reducing inorganic fertilizers (SR) to investigate C sequestration and exogenous N uptake using 13C pulse and 15N isotope tracer techniques.  The SR treatment had significantly higher soil 13C abundance, by 24.4 and 25.4%, respectively, 13C concentrations in aboveground plant parts, by 18.4 and 35.8% respectively, and 15N concentrations in rice panicles, by 12.8 and 34.3% than the SBR and F treatments.  This enhancement contributed to a higher total organic C concentration and increased rice grain yield in the SR treatment.  Furthermore, the SR treatment had significantly higher photosynthetic C, by 9.8%, which was directly transferred to soil C.  The SR treatment had a higher distribution of photosynthetic C in the leaves and stems, but a lower distribution in the panicle compared to the SBR treatment.  This finding is advantageous for sequestering photosynthetic C into the soil through straw return; conversely, opposite trends were observed in 15N distribution.  In addition, rice plants in the SR treatment had increased N uptake from urea and soil N sources, enhancing N recovery by 9.2 and 12.5%, respectively, and reducing soil N residues.  Correlation analysis showed that the SR treatment increased the concentrations of 13C in leaves and roots while decreasing the 15N abundance in all rice organs, thereby contributing to an increase in rice yield.  The partial least square path model suggested that the increase in rice yield under the SR treatment was primarily linked to 13C accumulation within the rice plant–soil system.  The results suggest that straw return increases the sequestration of photosynthetic C and exogenous N in the rice plant–soil system and increases N utilization efficiency, which subsequently improves both rice and soil productivity.

Key words: long-term straw return , 13C pulse labelling ,  15N isotope tracer, rice plant-soil system ,  photosynthetic C ,  nitrogen utilization efficiency