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土壤活性有机碳(LOC)是一组活跃的化学物质,由于其较短的周转时间和对环境变化的敏感性在全球碳循环中发挥着重要的作用。但是,对活性有机碳在亚热带森林沿海拔梯度的空间变异还缺乏了解。在本研究中,我们测定了福建武夷山自然保护区不同海拔高度具有代表性的中亚热带常绿阔叶林(500 m)、针叶林(1150 m)、亚高山矮林(1750 m)以及高山草甸(2150 m)土壤不同土层(0-10,10-25和25-40 cm)中微生物可利用碳(MAC)、微生物量碳(MBC)、易氧化碳(ROC)、水溶性碳(WSOC)和轻组碳(LFC),并观测了相应的植物凋落物质量(LM),土壤温度和湿度。结果表明:沿海拔梯度的植被变化和土层深度变化对土壤活性有机碳有显著的影响。微生物可利用碳、微生物量碳、易氧化碳和水溶性碳在不同土层均沿海拔高度的增加而显著增加;而低海拔的常绿阔叶林和针叶林中轻组碳的含量高于亚高山矮林和高山草甸的轻组碳的含量。各土壤活性有机碳库均随土层的加深而减小。除轻组碳外,各碳库间存在着极显著的正相关(p<0.001)。轻组碳分别在低海拔(常绿阔叶林和针叶林)和高海拔(亚高山矮林和高山草甸)与各碳库显著相关。
Soil active organic carbon (LOC) is a group of active chemicals that play an important role in the global carbon cycle due to its short turnaround time and its sensitivity to environmental changes. However, there is a lack of understanding of the spatial variation of active organic carbon along the altitudinal gradient of subtropical forests. In this study, we measured the subtropical evergreen broad-leaved forest (500 m), the coniferous forest (1150 m), the sub-alpine dwarf forest (1750 m) and the alpine mountain forests at different altitudes in Fujian Wuyishan Nature Reserve Microbial carbon (MAC), microbial biomass carbon (MBC), carbon dioxide (ROC) and water-soluble carbon in different soil layers (0-10, 10-25 and 25-40 cm) (WSOC) and light carbon (LFC), and observed the corresponding plant litter quality (LM), soil temperature and humidity. The results showed that: the changes of vegetation along the altitudinal gradient and soil depth had significant effects on soil active organic carbon. Microbial available carbon, microbial biomass carbon, readily oxidizable carbon and water-soluble carbon increased significantly in different soil layers along with the increase of altitude. However, the content of light carbon in low-altitude evergreen broad-leaved forest and coniferous forest was higher than that in subtropical Alpine meadow and alpine meadow light carbon content. The soil active organic carbon pools decreased with the deepening of soil layers. Except light group carbon, there was a very significant positive correlation (p <0.001) among the carbon stocks. Light carbon was significantly correlated with carbon pools at low altitude (evergreen broad-leaved forest and coniferous forest) and at high altitude (sub-alpine and alpine meadow), respectively.