甘南黄河流域4种典型林分土壤C、N、P化学计量特征

土壤碳（C）、氮（N）、磷（P）是参与植物光合作用和影响生态系统初级生产力的主要元素。甘南高原是黄河流域重要的生态屏障，为了解该区不同林分土壤养分状况的差异，选取该区4种典型林分：云杉林、华北落叶松林、巴山冷杉林以及岷江冷杉糙皮桦混交林为研究对象，研究土壤C、N、P化学计量特征。结果表明：（1）岷江冷杉及糙皮桦混交林土壤C、N含量最高，云杉林土壤N、P含量最低。不同林分间P含量差异显著（P<0.05），不同土层间C、N含量差异均显著（P<0.05）。（2）云杉林土壤C ： N值显著高于其他林分，岷江冷杉及糙皮桦混交林土壤N ： P及C ： P高于其他林分。（3）海拔、土壤pH、容重与土壤含水量是影响土壤养分的重要因素。土壤C含量与N、P含量均显著相关（P<0.05）。总体来说，不同林分土壤化学计量特征具有显著差异，混交林土壤养分状况较纯林好，未来森林管理和植被建设中，可以通过选择合适的树种和提高树种多样性有效改善森林土壤质量。

The stoichiometric characteristics of soil C, N and P in four typical forest stands in the Yellow River Basin in Gannan

Soil carbon (C), nitrogen (N), and phosphorus (P) are the main elements involved in plant photosynthesis and affect the primary productivity of ecosystems. Gannan Plateau is an important ecological barrier of the Yellow River Basin. In order to understand the difference in soil nutrients of different forest stands in this area, four typical stands including the pure forest of Picea asperata, Larix principis, Abies fargesii, and the mixed forest of Betula utilis and Abies faxoniana were selected to research the soil C, N, P stoichiometric characteristics. The results showed that the soil C and N contents were the highest in the mixed forest of Abies faxoniana and Betula utilis, while soil N and P were the lowest in Picea asperata. The contents of P changed significantly between different forest stands (P<0.05), and the contents of C and N changed significantly between different soil layers (P<0.05). In addition, the soil C:N value of the Picea asperata was significantly higher than that of other stands. In contrast, the soil N:P and C:P in the mixed forest of Abies faxoniana and Betula utilis were higher than those in other stands. The altitude, soil pH, bulk density and water content were important factors affecting soil nutrients. Soil C content was significantly correlated with soil N and P content (P<0.05). In general, the soil stoichiometric characteristics of different stands had significant differences, and the soil nutrient status of the mixed forest was better than that of pure forests. In the future, it is possible to improve forest soil quality by selecting appropriate species and increasing tree species diversity in forest management and vegetation construction.