Global atmospheric nitrogen deposition significantly affects the nutrient cycling and C–N–P stoichiometry in ecosystems. Herein, a global meta-analysis was conducted based on 898 pairwise observations to analyze the impact of nitrogen addition on plant-soil-enzyme C–N–P stoichiometry and microbial nutrient limitation in different ecosystem types (cropland, grassland, and forest), nitrogen addition intensity (0–5, 5–10, and >10 g N m⁻² yr⁻¹) and duration (0–5, 5–10, and >10yr). Results showed that nitrogen addition significantly decreased plant C:N (shoot: 16.5%, root: 27.1%, litter: 16.5%), soil C:N (5.9%), enzyme C:P (1.2%), and enzyme N:P (5.1%), whereas significantly increased soil C:P (4.9%), enzyme C:N (7.1%), vector angle (4.4%), vector length (3.9%), and plant N:P (shoot: 24.1%, root: 23.8%, and litter: 13.5%). Furthermore, nitrogen addition mainly affected the enzyme C:N and vector length in grasslands. Additionally, the changes in C:N in plants, soil, and enzymes, and vector angle and length were higher at nitrogen addition intensity of >10 g N m⁻² yr⁻¹. The changes in C:N and C:P in plant and soil were higher at nitrogen addition duration of >10 yr. Finally, the N:P in shoot, soil and enzyme, and vector angle were strongly correlated with mean annual precipitation (MAP). In conclusion, nitrogen addition significantly reduced the C:N ratio in plants and soil and increased plant N:P, and microbial C and P limitation. These effects vary with the ecosystem type, MAP, and nitrogen addition intensity and duration. The results improve our understanding of the plant-soil-microbial nutrient cycling processes in terrestrial ecosystems under global nitrogen deposition.

全球大气氮沉降显着影响生态系统中的养分循环和 C-N-P 化学计量。在此，基于 898 个成对观察结果进行了一项全球荟萃分析，以分析氮添加对不同生态系统类型（农田、草地和森林）中植物-土壤-酶 C-N-P 化学计量和微生物养分限制的影响，氮添加强度（0-5、5-10 和 >10 g N m ^-2 yr ^-1) 和持续时间（0-5、5-10 和 >10 年）。结果表明，施氮显着降低了植物 C:N（芽：16.5%，根：27.1%，凋落物：16.5%）、土壤 C:N（5.9%）、酶 C:P（1.2%）和酶 N： P（5.1%），而显着增加土壤 C:P（4.9%）、酶 C:N（7.1%）、载体角度（4.4%）、载体长度（3.9%）和植物 N:P（芽：24.1 %，根：23.8%，凋落物：13.5%）。此外，氮添加主要影响草地中的酶C：N和载体长度。^{此外，在氮添加强度 >10 g N m -2} yr ^-1时，植物、土壤和酶中 C:N 的变化以及载体角度和长度的变化更高。. 植物和土壤中 C:N 和 C:P 的变化在氮添加持续时间 > 10 年时更高。最后，枝条、土壤和酶中的 N:P 以及载体角度与年平均降水量 (MAP) 密切相关。总之，氮添加显着降低了植物和土壤中的 C:N 比，增加了植物 N:P 和微生物 C 和 P 限制。这些影响因生态系统类型、MAP 以及氮添加强度和持续时间而异。这些结果提高了我们对全球氮沉降下陆地生态系统植物-土壤-微生物养分循环过程的理解。