Background and Aims

Plant and microbial-derived carbon (C) constitute the soil C pool and determine its response to N deposition. However, the response of plant and microbial-derived C to exogenous N input in forest soils, accounting for 70% of the global soil C, remains unclear.

Methods

We conducted a global meta-analysis to assess the response of microbial-derived C (indicated by amino sugars) and plant-derived C (indicated by lignin phenols) in forest soils to the increasing N deposition.

Results

Results revealed significant increases in both total amino sugar and lignin phenols, with a more pronounced increase in temperate forest soils experiencing low-level N addition. Glucosamine (GluN) exhibited no significant change, but muramic acid (MurN) was increased following N addition. Positive correlations were observed between total amino sugars and SOC and total phospholipid fatty acid (PLFA), as well as between MurN and bacterial PLFA. Lignin phenols were positively correlated with litterfall but unrelated to root biomass.

Conclusion

N deposition enhanced the accumulation of microbial and plant-derived C in soils, particularly in N-deficient temperate forest soils. The accumulation of microbial-derived C is primarily attribute to the increased microbial biomass and bacterial-derived C, while the accrual plant-derived C is mainly associated with the increase in aboveground C input caused by N addition. These findings collectively uncover the general patterns and mechanisms of microbial and plant-derived C in forest soils in response to N deposition, providing new insights into interpreting soil C dynamics and predicting soil C pools in forest ecosystems facing future climate changes.

中文翻译：

---

氮沉降增强森林土壤中微生物和植物源碳的积累：全球荟萃分析

背景和目标

植物和微生物来源的碳 (C) 构成土壤碳库并决定其对氮沉降的响应。然而，森林土壤中植物和微生物来源的碳对外源氮输入的响应仍不清楚，森林土壤占全球土壤碳的 70%。

方法

我们进行了一项全球荟萃分析，以评估森林土壤中微生物来源的碳（以氨基糖表示）和植物来源的碳（以木质素酚表示）对增加的氮沉降的响应。

结果

结果显示，总氨基糖和木质素酚均显着增加，其中在低水平氮添加的温带森林土壤中增加更为明显。葡萄糖胺（GluN）没有表现出显着变化，但胞壁酸（MurN）在添加氮后增加。总氨基糖与 SOC 和总磷脂脂肪酸 (PLFA) 之间以及 MurN 与细菌 PLFA 之间均观察到正相关。木质素酚与凋落物呈正相关，但与根生物量无关。

结论

氮沉降增强了土壤中微生物和植物来源的碳的积累，特别是在缺氮的温带森林土壤中。微生物源碳的积累主要归因于微生物生物量和细菌源碳的增加，而植物源碳的累积主要与氮添加引起的地上碳输入的增加有关。这些发现共同揭示了森林土壤中微生物和植物来源的碳响应氮沉降的一般模式和机制，为解释土壤碳动态和预测森林生态系统面临未来气候变化的土壤碳库提供了新的见解。