<b>The effects, patterns, and predictors of phosphorus addition on terrestrial litter decomposition </b>raw data.xlsx

Elevated phosphorus (P) deposition profoundly affects carbon (C) and nutrient dynamics in terrestrial and aquatic ecosystems, which poses a threat to soil health and nutrient sustainability. Litter decomposition is crucial for maintaining soil C and nutrient pools, yet there is a significant knowledge gap regarding the effects of elevated P deposition on global-scale litter decomposition. To address this, we conducted a global meta-analysis of 731 observations from 261 field studies to investigate the impact of P addition on litter decomposition. Our analysis revealed that P addition increased the activities of β-1,4-glucosidase (BG) and β-1,4-N-acetylglucosaminidase (NAG) during decomposition. This increase in enzyme activity accelerated the degradation of lignin and cellulose and the release of litter C and nitrogen (N). Ultimately, this resulted in a 6.42% increase in litter mass loss. The positive effect of P addition on litter mass loss was further amplified when combined with N addition. The effects of P addition on litter decomposition varied depending on P fertilizer type (e.g., Ca(H2PO4)2, NaH2PO4, and KH2PO4), P addition level (e.g., &lt;5, 5-10, and &gt;10 g P m-2 year-1), experimental duration (e.g., &lt;12, 12-24, and &gt;24 months), and ecosystem type. Model selection analysis indicated that soil pH was the primary predictor driving global-scale litter decomposition in response to P addition. In conclusion, P addition overall accelerated litter decomposition due to increased activities of BG and NAG. However, the patterns varied with N availability, P fertilizer type, P addition level, experimental duration, and ecosystem type. Future studies should thus consider the effects, patterns, and drivers of P addition on litter decomposition when guiding sustainable practices in nutrient management.

磷（P）沉降增加会深刻影响陆地与水生生态系统中的碳（C）及养分动态平衡，对土壤健康与养分可持续性构成威胁。枯落物分解对于维持土壤碳与养分库至关重要，但目前关于磷沉降增加对全球尺度枯落物分解的影响，仍存在显著的认知空白。为填补这一研究空白，我们整合了261项野外研究的731组观测数据开展全球尺度元分析，以探究磷添加对枯落物分解的影响。分析结果显示，磷添加可提升分解过程中β-1,4-葡萄糖苷酶（β-1,4-glucosidase, BG）与β-1,4-N-乙酰氨基葡萄糖苷酶（β-1,4-N-acetylglucosaminidase, NAG）的活性。酶活性的提升加速了木质素与纤维素的降解，以及枯落物碳（C）和氮（N）的释放，最终使得枯落物质量损失率提升6.42%。当磷添加与氮添加联合施用时，其对枯落物质量损失的促进作用会进一步增强。磷添加对枯落物分解的影响因磷肥类型（如磷酸二氢钙Ca(H₂PO₄)₂、磷酸二氢钠NaH₂PO₄及磷酸二氢钾KH₂PO₄）、磷添加水平（如<5、5~10及>10 g P·m⁻²·a⁻¹）、实验周期（如<12、12~24及>24个月）以及生态系统类型而异。模型选择分析表明，土壤pH是调控全球尺度下磷添加响应下枯落物分解的核心预测因子。综上，磷添加整体上通过提升BG与NAG的活性加速了枯落物分解，但这一效应的具体模式会随氮素有效性、磷肥类型、磷添加水平、实验周期及生态系统类型的不同而发生变化。因此，未来在制定养分管理可持续实践方案时，应充分考虑磷添加对枯落物分解的影响、效应模式及其驱动机制。