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Aims <p>This study aimed to elucidate the regulatory mechanisms of nitrogen fertilization and rhizosphere processes on carbon dioxide emissions derived from soil inorganic carbon (SIC) in a winter wheat–summer maize rotation system; employing a field-based isotopic (δ¹³C) partitioning approach to quantify the contribution of SIC to total soil respiration and assess its interaction with agronomic practices.</p> Methods <p>The experiment comprised four nitrogen (N) application rates: 0, 200, 400, and 600&#xa0;kg N ha⁻¹, each with paired root-free and rhizosphere sub-treatments. Emissions of CO₂ from SIC sources were distinguished and quantified during the wheat and maize growing seasons using the natural abundance of ¹³C.</p> Results <p>Both nitrogen application and root presence significantly enhanced SIC-derived CO₂ emissions, with rhizosphere soils consistently exhibiting higher cumulative fluxes than root-free soils across all nitrogen levels; the proportional contribution of SIC was markedly higher in the wheat season (up to 56%) compared to maize (27%), revealing a crop-specific dynamic. Nitrogen stimulation followed a non-linear pattern, with the strongest response observed at intermediate application rates (N200–N400) in maize, while high nitrogen (N600) further promoted emissions in wheat.</p> Conclusions <p>The study demonstrates that soil inorganic carbon constitutes a substantial and previously underestimated source of CO₂ in calcareous croplands, especially under wheat cultivation; the synergistic effects of nitrogen management and rhizosphere activity critically regulate SIC dynamics, suggesting that optimized fertilization and root-zone management could serve as effective strategies to mitigate greenhouse gas emissions while maintaining soil health and agricultural productivity.</p>

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Regulatory effects of nitrogen application and rhizosphere effects on carbon dioxide emissions from inorganic carbon sources in the soil of a wheat-maize rotation system

  • 期刊论文

  • 发表日期：

    2026年6月15日

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  • Can Chen,
  • Tingting Zeng,
  • Jing Wang,
  • Wenxu Dong,
  • Chunsheng Hu

摘要

Aims

This study aimed to elucidate the regulatory mechanisms of nitrogen fertilization and rhizosphere processes on carbon dioxide emissions derived from soil inorganic carbon (SIC) in a winter wheat–summer maize rotation system; employing a field-based isotopic (δ¹³C) partitioning approach to quantify the contribution of SIC to total soil respiration and assess its interaction with agronomic practices.

Methods

The experiment comprised four nitrogen (N) application rates: 0, 200, 400, and 600 kg N ha⁻¹, each with paired root-free and rhizosphere sub-treatments. Emissions of CO₂ from SIC sources were distinguished and quantified during the wheat and maize growing seasons using the natural abundance of ¹³C.

Results

Both nitrogen application and root presence significantly enhanced SIC-derived CO₂ emissions, with rhizosphere soils consistently exhibiting higher cumulative fluxes than root-free soils across all nitrogen levels; the proportional contribution of SIC was markedly higher in the wheat season (up to 56%) compared to maize (27%), revealing a crop-specific dynamic. Nitrogen stimulation followed a non-linear pattern, with the strongest response observed at intermediate application rates (N200–N400) in maize, while high nitrogen (N600) further promoted emissions in wheat.

Conclusions

The study demonstrates that soil inorganic carbon constitutes a substantial and previously underestimated source of CO₂ in calcareous croplands, especially under wheat cultivation; the synergistic effects of nitrogen management and rhizosphere activity critically regulate SIC dynamics, suggesting that optimized fertilization and root-zone management could serve as effective strategies to mitigate greenhouse gas emissions while maintaining soil health and agricultural productivity.