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Background and aims <p>Human-induced increases in nitrogen (N) and phosphorus (P) deposition are considered significant threats to soil carbon (C) sequestration in northern peatlands. However, this hypothesis lacks validation with long-term simulation experiments and dating technology, which are crucial for accurately assessing C storage.</p> Methods <p>Using accelerator mass spectrometry (AMS) <sup>14</sup>C dating technology, we examined the effect of 13&#xa0;years N and P additions on soil C storage in a <i>Sphagnum</i> dominated peatland.</p> Results <p>AMS <sup>14</sup>C dating showed that apparent soil accumulation rate decreased from 0.94 in control to 0.74&#xa0;cm&#xa0;yr<sup>−1</sup> on average in nutrient addition plots. However, the soil C storage in the past 50&#xa0;years was not reduced by N or low level of P additions due to accelerated peat decomposition being offset by more belowground biomass inputs. We found that high level of P additions increased C storage significantly (up to 30%). The additions of N, P or their co-addition increased the ratio of soil labile organic C to total organic C, suggesting a potential decrease in stability due to a shift towards less stable C. Comparatively, microbial and enzyme activities were more sensitive to P addition.</p> Conclusion <p>The chronic exogenous nutrient enrichment may facilitate C sequestration to some extent, but it could threaten C sink by diminishing the stability of soil C fractions in peatlands in the long run. The contrasting responses of the quality and quantity of C pool to long-term nutrient enrichment may explain the underlying mechanisms of C dynamics in peatlands.</p>

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Additions of nitrogen and phosphorus do not reduce storage but stability of soil carbon in a northern peatland

  • 期刊论文

  • 发表日期：

    2025年4月23日

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  • Si-Nan Wang,
  • Xu Chen,
  • Jun-Xiao Ma,
  • Xuan Liu,
  • Azim Mallik,
  • Meng Wang,
  • Shasha Liu,
  • Mingming Zhang,
  • Zhao-Jun Bu

摘要

Background and aims

Human-induced increases in nitrogen (N) and phosphorus (P) deposition are considered significant threats to soil carbon (C) sequestration in northern peatlands. However, this hypothesis lacks validation with long-term simulation experiments and dating technology, which are crucial for accurately assessing C storage.

Methods

Using accelerator mass spectrometry (AMS) 14C dating technology, we examined the effect of 13 years N and P additions on soil C storage in a Sphagnum dominated peatland.

Results

AMS 14C dating showed that apparent soil accumulation rate decreased from 0.94 in control to 0.74 cm yr−1 on average in nutrient addition plots. However, the soil C storage in the past 50 years was not reduced by N or low level of P additions due to accelerated peat decomposition being offset by more belowground biomass inputs. We found that high level of P additions increased C storage significantly (up to 30%). The additions of N, P or their co-addition increased the ratio of soil labile organic C to total organic C, suggesting a potential decrease in stability due to a shift towards less stable C. Comparatively, microbial and enzyme activities were more sensitive to P addition.

Conclusion

The chronic exogenous nutrient enrichment may facilitate C sequestration to some extent, but it could threaten C sink by diminishing the stability of soil C fractions in peatlands in the long run. The contrasting responses of the quality and quantity of C pool to long-term nutrient enrichment may explain the underlying mechanisms of C dynamics in peatlands.