Carbon:nitrogen:phosphorus (C:N:P) stoichiometry plays a critical role in nutrient cycling, biodiversity, and ecosystem functionality. However, our understanding of the responses of C:N:P stoichiometry to elevation and forest management remains elusive. Here we sampled 18 Larix principis-rupprechtii sites along altitudinal gradients (1700-2300 m) on Guandishan Mountain in the Loess Plateau, China. We determined the leaf, litter, and soil C N P contents and C:N:P stoichiometric ratios, as well as nutrient resorption efficiency (NuRE), and diameter at breast height (DBH) increments in both planted and natural stands, and then tested the impacts of elevation and stand origin on these parameters’ management. We found different C:N:P stoichiometry between natural and planted forests. The results revealed that: soil C, N, and N:P ratios, litter C:P and N:P ratios, leaf C:N and N:P ratios increased significantly; however, soil C:N ratios, litter P, leaf N and P, nitrogen resorption efficiency (NRE), and DBH increments decreased significantly with elevation in the planted forests. Soil C,N and N:P ratios, litter C, as well as C:N and C:P ratios increased significantly with elevation in natural forests. The soil N, P and N:P ratios, litter C:P and N:P ratios, leaf C, C:P and N:P ratios, nitrogen resorption efficiency (NRE), phosphorus resorption efficiency (PRE), and DBH increments were, on average, higher in the planted, rather than natural forests. Our results indicated that there was an enhancing P-limitation in both the planted and natural forests, and the plantations were more restricted by P. Moreover, compared to natural forests, plantations converged toward a higher conservative N- and P-use strategy by enhancing resorption efficiencies of internal nutrient cycling and a higher annual growth rate.

中文翻译：

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黄土高原人工林和天然华北落叶松林分的C：N：P化学计量

碳：氮：磷（C：N：P）的化学计量在养分循环，生物多样性和生态系统功能方面发挥关键作用。但是，我们对C：N：P化学计量对海拔和森林经营的反应的了解仍然难以捉摸。在这里我们取样了18个Larix principis-rupprechtii黄土高原关帝山海拔高度梯度（1700-2300 m）我们确定了人工林和自然林中叶片，凋落物和土壤的CNP含量，C：N：P化学计量比，养分吸收效率（NuRE）和胸高直径（DBH）增量，然后进行了测试。海拔和林分原点对这些参数管理的影响。我们发现天然和人工林之间的C：N：P化学计量不同。结果表明：土壤C，N和N：P比，凋落物C：P和N：P比，叶片C：N和N：P比显着增加；但是，随着人工林海拔的升高，土壤碳氮比，凋落物磷，叶氮和磷，氮吸收效率（NRE）和DBH增量显着下降。土壤C，N和N：P比率，垫料C以及C：N和C：磷的比例随着天然林中海拔的升高而显着增加。土壤N，P和N：P比率，凋落物C：P和N：P比率，叶子C，C：P和N：P比率，氮吸收效率（NRE），磷吸收效率（PRE）和DBH增量平均而言，人工林比天然林要高。我们的结果表明，人工林和天然林中的P限均得到增强，人工林受P的限制更大。此外，与天然林相比，人工林通过提高P限制而趋向于更高的保守氮和P利用策略内部养分循环的吸收效率更高，年增长率更高。在人工林而非天然林中，磷的吸收效率（PRE）和DBH增量平均较高。我们的结果表明，人工林和天然林中的P限均得到增强，人工林受P的限制更大。此外，与天然林相比，人工林通过提高P限制而趋向于更高的保守氮和P利用策略内部养分循环的吸收效率更高，年增长率更高。在人工林而非天然林中，磷的吸收效率（PRE）和DBH增量平均较高。我们的结果表明，人工林和天然林中的P限均得到增强，人工林受P的限制更大。此外，与天然林相比，人工林通过提高P限制而趋向于更高的保守氮和P利用策略内部养分循环的吸收效率更高，年增长率更高。