福建三种常绿阔叶林碳氮磷生态化学计量特征

为探明福建三种常绿阔叶林生态系统的养分循环状况及其主要影响因素，采用样地调查采样法，研究了福建武夷山自然保护区甜槠（Castanopsis eyrei）林、天宝岩自然保护区刨花润楠（Machilus pauhoi）林和虎伯寮自然保护区薄叶润楠（Machilus leptophylla）林的植物、凋落物和表层土壤（0-10 cm）碳（C）、氮（N）、磷（P）含量、化学计量特征及其与环境因子的相关性。结果表明：（1）比较3个样点同组分C、N和P含量，除了乔木层的N含量外，虎伯寮植物和凋落物层C、N和P含量均显著高于天宝岩和武夷山；武夷山表层土壤的C和N含量显著高于虎伯寮和天宝岩，P含量排序为天宝岩>武夷山>虎伯寮。（2） P是福建天然林植物生长的主要限制因子，土壤P的缺乏是影响福建常绿阔叶林养分循环的重要因素。（3）植物叶片与凋落物中的养分含量及化学计量比呈极显著正相关，与表层土壤呈极显著负相关，可见福建常绿阔叶林生态系统养分循环过程中，土壤养分消耗速率超过了凋落物的养分供给速率，导致生态系统养分循环缓慢。（4）气温和土壤C ∶ N是影响常绿阔叶林生态系统养分循环的关键环境因子。

Ecostoichiometric characteristics of carbon, nitrogen and phosphorus in Fujian evergreen broad-leaved forest

In order to understand the nutrient cycling of evergreen broad-leaved forest ecosystem in Fujian Province, the typical forests of Wuyishan, Tianbaoyan and Huboliao National Nature Reserve were studied. The carbon (C), nitrogen (N), phosphorus (P) concentrations of plant, litter and the topsoil (0-10cm) were explored. We had mastered the correlation among them through analyzing the ecological stoichiometry and the redundancy analysis (RDA) was used to study relationships between the measurement results and environmental factors. The results show that (1) the C, N and P concentrations in vegetation and litter layers of Huboliao (except the N concentration of tree layer) were higher than those of Wuyishan and Tianbaoyan. The C and N concentrations in topsoil of Wuyishan were higher than those of Tianbaoyan and Huboliao, while the trend of P concentration was Tianbaoyan > Wuyishan > Huboliao. (2) P was the main limiting factor of plant growth in evergreen broad-leaved forests. The lack of P concentration in topsoil was seriously harmful for nutrient cycling of evergreen broad-leaved forest ecosystem. (3) The concentrations and stoichiometry characteristics of C, N and P in leaves had significantly positive correlations with those in the litter, and had significantly negative correlations with those in the topsoil. The nutrient turnover rate of evergreen broad-leaved forest ecosystem was slowly due to the slower litter decomposition rate, which caused soil nutrient deficiencies. (4) The RDA showed that the nutrient circulation of evergreen broad-leaved forest ecosystem was mainly affected by atmospheric temperature and soil C:N.