Ren Yue, Gao Guang-Lei, Ding Guo-Dong, Zhang Ying, Zhao Pei-Shan
Yanchi Research Station, School of Soil and Water Conservation Beijing Forestry University Beijing China.
State Key Laboratory of Efficient Production of Forest Resources Beijing Forestry University Beijing China.
Ecol Evol. 2024 Mar 20;14(3):e11172. doi: 10.1002/ece3.11172. eCollection 2024 Mar.
Ecological stoichiometry is an important approach to understand plant nutrient cycling and balance in the forest ecosystem. However, understanding of stoichiometric patterns through the leaf-litter-soil system of Mongolian pine among different stand origins is still scarce. Therefore, to reveal the variations in Mongolian pine carbon (C), nitrogen (N), and phosphorus (P) stoichiometry and stoichiometric homeostasis among different stand origins, we measured C, N, and P concentrations of leaves, litter, and soil, and analyzed the nutrient resorption efficiencies of leaves in differently aged plantations and natural forests from semi-arid and dry sub-humid regions. The results showed that (1) the stand origin had a significant effect on the C-N-P stoichiometry, and also significantly affected leaf N and P reabsorption efficiencies. Leaf N/P ratios indicated that Mongolian pine was co-limited by N and P in the NF, HB and HQ, and was mainly limited by P in MU. (2) With increasing stand age, C concentrations in the leaf-litter-soil system initially increased and then decreased, the N and P concentrations and reabsorption efficiencies in the leaf-litter-soil system were gradually increased. Overall, stand age had a significant effect on N concentrations, C/N and C/P ratios in the leaf-litter-soil system. (3) The C and N elements between the leaf-litter-soil system had a strong coupling relationship, and the P element between litter-soil had a strong coupling relationship. In addition, plantations exhibited greater N/P homeostasis than natural forests, and N/P exhibited greater homeostasis than N and P alone, which may be a nutrient utilization strategy for forests to alleviate N or P limitation. (4) Environmental factors have a significant influence on C-N-P stoichiometry in the leaf-litter-soil system, the most important soil properties and meteorological factors being soil water content and precipitation, respectively. These results will be essential to provide guidance for plantation restoration and management in desert regions.
生态化学计量学是理解森林生态系统中植物养分循环与平衡的重要方法。然而，关于不同林分起源的樟子松通过叶—凋落物—土壤系统的化学计量模式的了解仍然很少。因此，为揭示不同林分起源的樟子松碳（C）、氮（N）和磷（P）化学计量及其化学计量内稳性的变化，我们测定了半干旱和半湿润偏旱地区不同龄人工林和天然林中叶片、凋落物和土壤的C、N、P浓度，并分析了叶片的养分重吸收效率。结果表明：（1）林分起源对C—N—P化学计量有显著影响，对叶片N和P重吸收效率也有显著影响。叶片N/P比表明，樟子松在天然林、火烧迹地和皆伐迹地受N和P共同限制，在蒙古栎林主要受P限制。（2）随着林分年龄增加，叶—凋落物—土壤系统中C浓度先增加后降低，N和P浓度及重吸收效率逐渐增加。总体而言，林分年龄对叶—凋落物—土壤系统中N浓度、C/N和C/P比有显著影响。（3）叶—凋落物—土壤系统中C和N元素具有较强的耦合关系，凋落物—土壤间P元素具有较强的耦合关系。此外，人工林比天然林表现出更大的N/P内稳性，且N/P比单独的N和P表现出更大的内稳性，这可能是森林缓解N或P限制的养分利用策略。（4）环境因素对叶—凋落物—土壤系统中C—N—P化学计量有显著影响，最重要的土壤性质和气象因素分别是土壤含水量和降水量。这些结果对于为荒漠地区人工林恢复和管理提供指导至关重要。
