Background and aims

Litter decomposition is essential for the global carbon cycle, which is affected by environmental factors. In the context of global warming and increasing nitrogen deposition, the responses of litter decomposition are unclear in subtropical forests.

Methods

Here, we carried out an interaction experiment of warming (3.3 °C) and nitrogen addition (50 kg ha⁻¹ yr⁻¹) and a recovery experiment (remove warming and nitrogen addition treatments) in a subtropical evergreen broad-leaved forest for four years in total.

Results

The results showed that during the treatment period, warming, nitrogen addition, and their combination significantly decreased litter decomposition according to the k values by 35.8%, 23.0%, and 42.2%, respectively. However, there was no significant interaction effect between warming and nitrogen addition. Litter decomposition rates quickly returned to the same level during the two-year recovery period. Variance partitioning analysis (VPA) and covariance analysis (ANCOVA) simultaneously confirmed that warming and nitrogen addition significantly affected litter decomposition. VPA and ANCOVA also showed that soil temperature and water content significantly contributed to the decomposition rate during the treatment period.

Conclusions

This study suggests that warming and nitrogen addition significantly inhibit litter decomposition, but this effect is not sustainable.

中文翻译：

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气候变暖和氮沉降对西南亚热带山地森林凋落物分解没有显着的交互作用

背景和目标

凋落物分解对于受环境因素影响的全球碳循环至关重要。在全球变暖和氮沉降增加的背景下，亚热带森林中凋落物分解的反应尚不清楚。

方法

在这里，我们在亚热带常绿阔叶林中进行了变暖（3.3 °C）和氮添加（50 kg ha ^-1  yr ^-1 ）的相互作用实验和恢复实验（去除变暖和氮添加处理），为期四个月总计年。

结果

结果表明，在处理期间，升温、添加氮以及它们的组合根据k值分别显着减少了凋落物分解35.8%、23.0%和42.2%。然而，变暖与氮添加之间没有显着的交互作用。在两年的恢复期内，凋落物分解率迅速恢复到相同水平。方差分配分析（VPA）和协方差分析（ANCOVA）同时证实变暖和氮添加显着影响凋落物分解。 VPA 和 ANCOVA 还表明，土壤温度和含水量对处理期间的分解速率有显着影响。

结论

这项研究表明，变暖和氮添加显着抑制凋落物分解，但这种效应是不可持续的。