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2011年12月至2012年9月,在湘中丘陵区杉木(Cunninghamia lanceolata)人工林、马尾松(Pinus massoniana)-石栎(Lithocarpus glaber)针阔混交林、南酸枣(Choerospondias axillaries)落叶阔叶林、石栎(Lithocarpus glaber)-青冈(Cyclobalanopsis glauca)常绿阔叶林1 hm2的长期定位观测样地,采集0–15 cm、15–30 cm土层土壤样品,测定土壤微生物生物量碳(MBC)、可矿化有机碳(MOC)、易氧化有机碳(ROC)、水溶性有机碳(DOC)含量,分析4种森林土壤MBC、MOC、ROC、DOC含量的季节变化特征,为揭示天然林保护与恢复对土壤有机碳(SOC)库的影响机理过程提供基础数据。结果表明:森林土壤MBC、MOC、ROC、DOC含量具有明显的季节动态,且不同森林同一土壤活性有机碳组分的季节变化节律基本一致,MBC、MOC、ROC含量表现为夏、秋季较高,春、冬季较低;DOC含量表现为春、夏、冬季较高,秋季最低;同一森林不同土壤活性有机碳组分含量的季节变化节律不同;土壤MBC、MOC、ROC、DOC含量与土壤自然含水率、SOC、全N、水解N、全P(除杉木人工林土壤MBC、MOC、ROC外)、速效P含量显著或极显著正相关,与土壤p H值、全K、速效K含量相关性不显著,表明不同森林类型外源碳库投入和土壤理化性质的差异是导致不同森林类型土壤活性有机碳含量差异显著的主要原因,该区域森林土壤活性有机碳各组分含量的季节变化与各森林类型组成树种生长节律及其土壤水分含量和SOC、N、P的可利用性,以及土壤活性有机碳各组分的来源有关,森林土壤MBC、MOC、ROC、DOC含量可作为衡量森林土壤C、N、P动态变化的敏感性指标。
From December 2011 to September 2012, Cunninghamia lanceolata plantations, Pinus massoniana-Lithocarpus glaber coniferous and broad-leaved mixed forest, Choerospondias axillaries deciduous broad-leaved forest Long-term location observation plots of Lithocarpus glaber-Cyclobalanopsis glauca evergreen broad-leaved forest, and soil samples of 0-15 cm and 15-30 cm soil layers were collected to measure soil microbial biomass carbon MBC, MOC, DOC and DOC contents in the four forest soils were analyzed to reveal the seasonal variation of MBC, MOC, ROC and DOC. Forest conservation and restoration of soil organic carbon (SOC) reservoir mechanism of the process to provide the basic data. The results showed that the contents of MBC, MOC, ROC and DOC in forest soil had obvious seasonal dynamics, and the rhythm of seasonal variation of active carbon in the same forest was the same. The contents of MBC, MOC and ROC were higher in summer and autumn, The content of MBC, MOC, ROC and DOC in soils varied with the natural water content of soils in spring, summer and winter; the content of DOC in soil was higher in spring, summer and winter and lowest in autumn; Total SOC, total N, total N, total P (except for Chinese fir plantation soil MBC, MOC and ROC), available P content were significantly or very significantly positively correlated with soil p H value, total K and available K content The results showed that the difference of soil organic carbon content in different forest types was the main reason for the significant difference in soil active organic carbon content in different forest types. Forest rhythm, soil water content, availability of SOC, N and P, and sources of soil active organic carbon components, forest soil MBC, MOC, ROC, DOC It can be used as a measure of the amount of forest soil C, N, sensitive indicators dynamics P.