武夷山不同海拔植被带土壤活性有机碳的季节变化

Seasonal variations of soil microbial available carbon in four plant communities along the altitude gradient in Wuyi Mountain

采用连续熏蒸-培养法（Sequential fumigation—incubation），测定福建武夷山自然保护区不同海拔具有代表性的中亚热带常绿阔叶林、针叶林、亚高山矮林以及高山草甸土壤中活性有机碳（MAC）的变化，分析MAC与土壤湿度、土壤温度、土壤总有机碳之间的关系。结果表明：（1）1年中，MAC在不同林分的0～10、10～25cm土层中的变化从大到小为：夏季、春季、秋季、冬季；每一季节中，不同林分的MAC从大到小为草甸、矮林、针叶林、阔叶林，且0～10cm土层中的MAC含量显著高于10～25cm土层中的；（2）在不同土层中，MAC与土壤湿度、土壤温度、土壤总有机碳之间均呈极显著相关。总之，武夷山山地森林MAC季节变化明显，夏季最大，冬季最小；土壤湿度、土壤温度可能是MAC季节变化的主要调控因子。

Microbial available carbon （MAC） was one of the most active and important parts of carbon cycle in terrestrial ecosystem. MAC dynamics were examined through a year, using a sequential fumigation-incubation procedure, in evergreen broadleaf forest（EBF） , coniferous forest（CF） , dwarf forest（DF） and alpine meadow（AM） , respectively, along the altitude in the natural preserve area in Wuyi Mountain in Fujian province, China, and relationship between MAC and soil moisture, soil temperature, and coil total organic carbon were analyzed. The results indicated： （ 1 ） Seasonal variations of microbial available carbon in each site along the altitude was significant both in 0-10 cm and 10-25 cm soil layers. In different types of forests, the magnitude of MAC was in a order of AM, DF, CF and EBF. MAC was significantly higher in the 0-10cm soil layer than that in the 10-25cm＇s. （2） There were positive correlations between MAC and soil moisture, soil temperature in each site and different layers. Our study showed that the MAC had obvious variations during a year, it reached the highest in summer, and the lowest in winter. MAC was greatly affected by soil moisture and soil temperature.