Aims

Soil comprises diverse carbon (C) pools undergoing various decomposition stages, each characterized by distinct stability and turnover rates. The response of these C pools to warming with the input of plant residues remains unclear.

Methods

We conducted a 90-day incubation study at 15 °C and 25 °C, introducing ¹³C-labeled cellulose into soils from old-field (OF), bare-fallow (BF), and bare-fallow plus 815-day pre-incubation (BF+) representing different stages of soil organic matter decomposition.

Results

We estimated the priming effects (PE) of cellulose and found that PE were 30.6%, 59.3%, and 63.0% at 15 °C, and 20.8%, 35.3%, and 39.8% at 25 °C for OF, BF, and BF + soils, respectively. Net C balance was higher in BF and BF + soils than in OF soil by 0.6 − 2.8 mg C g⁻¹ SOC at 15 °C and 1.8 − 3.8 mg C g⁻¹ SOC at 25 °C. This indicated both PE and net C balance declined with warming regardless of soil C pool stability, but much greater in soil C pools at a slower decomposition stage.

Conclusions

Overall, this study underscores warming can uniformly decrease soil C sequestration potential although the distinct priming effects of the soil C pools at different decomposition stages.

中文翻译：

---

无论土壤碳库的分解阶段如何，纤维素输入的启动效应都会随着变暖而减弱

目标

土壤由经历不同分解阶段的不同碳（C）库组成，每个阶段都具有不同的稳定性和周转率。这些碳库对植物残留物输入引起的变暖的反应仍不清楚。

方法

我们在 15 °C 和 25 °C 下进行了 90 天的培养研究，将¹³ C 标记的纤维素引入旧田 (OF)、裸地 (BF) 和裸地休耕加上 815 天预培养的土壤中。孵化（BF+）代表土壤有机质分解的不同阶段。

结果

我们估计了纤维素的启动效应 (PE)，发现 OF、BF 和 BF 在 15 °C 时的 PE 分别为 30.6%、59.3% 和 63.0%，在 25 °C 时为 20.8%、35.3% 和 39.8% + 土壤，分别。 BF 和 BF + 土壤的净碳平衡比 O​​F 土壤高，15 °C 时高 0.6 − 2.8 mg C g ⁻¹ SOC，25 °C 时高 1.8 − 3.8 mg C g ⁻¹ SOC。这表明，无论土壤碳库稳定性如何，PE 和净碳平衡都随着变暖而下降，但在分解较慢的阶段，土壤碳库的下降幅度要大得多。

结论

总体而言，这项研究强调，尽管土壤碳库在不同分解阶段具有不同的启动效应，但变暖会一致降低土壤碳固存潜力。