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<p>Biochar is increasingly promoted as a strategy for mitigating soil nitrous oxide (N<sub>2</sub>O) emissions, yet its effect on the temperature sensitivity (Q<sub>10</sub>) of N<sub>2</sub>O emissions remains poorly understood. In this study, short-term incubation experiments were conducted using two contrasting soils (agricultural and forest soils) amended with two biochar types (wood- and rice husk-derived) at three application rates (0, 1%, and 3%) under three temperatures (10&#xa0;°C, 20&#xa0;°C, 30&#xa0;°C). We investigated how biochar alters Q<sub>10</sub> of N<sub>2</sub>O emissions and explored the underlying mechanisms. Results showed that cumulative N<sub>2</sub>O emissions increased with temperature in both soils, with higher Q<sub>10</sub> values in forest soils (1.63–2.84) than in agricultural soils (1.13–1.63). Only high-rate wood biochar (WH) significantly changed Q<sub>10</sub>, decreasing it in agricultural soils but increasing it in forest soils. In agricultural soils, WH strongly reduced NO<sub>3</sub><sup>−</sup>–N availability and minimized its temperature response, intensifying substrate limitation and lowering Q<sub>10</sub>. In forest soils, biochar accelerated the decline of NH<sub>4</sub><sup>+</sup>–N and slowed the increase of NO<sub>3</sub><sup>−</sup>–N with temperature, suggesting tighter coupling between nitrification and nitrate-consuming processes. Although WH and high rate rice-husk biochar showed the smallest NO<sub>3</sub><sup>−</sup>-temperature slopes, the unique properties of WH (e.g., low ash content, higher aromaticity, and larger pore size) may have promoted short-term NO<sub>3</sub><sup>−</sup> retention, thereby strengthening temperature-coupled nitrification–denitrification turnover, which likely contributed to the higher Q<sub>10</sub> observed under WH. Partial least squares path modeling (PLS-PM) confirmed that temperature exerted stronger total effects on N<sub>2</sub>O emissions&#xa0;than biochar through changes in substrate availability, pH, and functional genes, while biochar acted as a secondary modulator. Overall, biochar regulated N<sub>2</sub>O Q<sub>10</sub> through soil-specific pathways, highlighting the need for soil-specific biochar application strategies under future climate change scenarios.</p> Graphical Abstract <p></p>

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Biochar modulates temperature sensitivity of soil N2O emissions: soil-specific mechanisms

  • 期刊论文

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  • 发表日期：

    2026年3月24日

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  • Siyu Luo,
  • Zhibo Li,
  • Jing Hu,
  • Xiaolin Liao

摘要

Biochar is increasingly promoted as a strategy for mitigating soil nitrous oxide (N2O) emissions, yet its effect on the temperature sensitivity (Q10) of N2O emissions remains poorly understood. In this study, short-term incubation experiments were conducted using two contrasting soils (agricultural and forest soils) amended with two biochar types (wood- and rice husk-derived) at three application rates (0, 1%, and 3%) under three temperatures (10 °C, 20 °C, 30 °C). We investigated how biochar alters Q10 of N2O emissions and explored the underlying mechanisms. Results showed that cumulative N2O emissions increased with temperature in both soils, with higher Q10 values in forest soils (1.63–2.84) than in agricultural soils (1.13–1.63). Only high-rate wood biochar (WH) significantly changed Q10, decreasing it in agricultural soils but increasing it in forest soils. In agricultural soils, WH strongly reduced NO3−–N availability and minimized its temperature response, intensifying substrate limitation and lowering Q10. In forest soils, biochar accelerated the decline of NH4+–N and slowed the increase of NO3−–N with temperature, suggesting tighter coupling between nitrification and nitrate-consuming processes. Although WH and high rate rice-husk biochar showed the smallest NO3−-temperature slopes, the unique properties of WH (e.g., low ash content, higher aromaticity, and larger pore size) may have promoted short-term NO3− retention, thereby strengthening temperature-coupled nitrification–denitrification turnover, which likely contributed to the higher Q10 observed under WH. Partial least squares path modeling (PLS-PM) confirmed that temperature exerted stronger total effects on N2O emissions than biochar through changes in substrate availability, pH, and functional genes, while biochar acted as a secondary modulator. Overall, biochar regulated N2O Q10 through soil-specific pathways, highlighting the need for soil-specific biochar application strategies under future climate change scenarios.

Graphical Abstract