【作者】 王国兵；

【导师】 阮宏华；

【作者基本信息】 南京林业大学 ， 生态学， 2008， 博士

【摘要】 本研究探讨了北亚热带天然次生栎林与火炬松人工林土壤有机碳输入和释放的动态变化以及土壤中各种形式有机碳含量的动态变化特征,并初步分析了其主要调控因子及调控机理。研究结果表明:（1）两种林分土壤呼吸均表现出明显的日动态和季节动态变化,土壤呼吸的季节性变异主要受土壤温度的控制,表现为夏季土壤呼吸速率最大而冬季最小,栎林土壤呼吸对温度的敏感性大于松林;（2）两种林分土壤微生物生物量碳含量均具有显著的季节动态变化,表现为在林木生长旺季土壤微生物生物量碳维持在较低水平,而在林木休眠季节,土壤微生物生物量碳维持在较高水平,这种季节性变异可能与土壤碳和养分的限制或与林木的生长发育节律有关;（3）土地利用方式的改变对土壤微生物生物量及土壤CO₂的释放有显著的影响,森林改变为农田可能潜在地增加土壤CO₂的释放;（4）两种林分土壤有机碳及土壤有效碳含量均具有一定的季节动态变化,并且变化特点各异;两种林分土壤有机碳的含量均呈现出下降趋势,并且栎林下降趋势更为明显;林地凋落物的输入和分解对于维持土壤有机碳及土壤有效碳的含量具有重要的作用。我们的研究成果为阐明北亚热带区域土壤碳循环特征及我国森林在全球碳平衡中的作用提供了科学依据。更多还原

【Abstract】 The dynamics and its main influence factors of soil organic carbon, soil labile carbon, soil microbial biomass carbon, soil respiration and plant litter fall input were studied in a secondary oak forest and a pine plantation in Xiashu Forest Experimental Site of Nanjing Forestry University, Jiangsu Province, South-eastern China. The field experients lasts two years with randomized block design. The results showed that: （1） There were significant diurnal variation and seasonal variation of soil respiration both in oak forest and pine plantation, the seasonal variation of soil respiration was mainly controlled by soil temperature, which was maximum in summer and minimum in winter, the Q₁₀ value in oak forest was higher than in pine plantation; （2） There were significant seasonal fluctuations of soil microbial biomass carbon both in secondary oak forest and pine plantation, which maintained at a lower level through the growing season in summer, but at a higher level during non-growing season in winter, the fluctuation of soil microbial biomass carbon wasn’t directly regulated by soil temperature, soil moisture, or aboveground litter fall input, which might be regulated by the availability of soil carbon and soil nutrients or competition for soil nutrients from plant roots at local scales within northern subtropical forests; （3） Land use change significantly influenced the soil respiration and soil microbial biomass, the land use change from forest to cropland may potentially increase the release of soil carbon dioxide; （4） There were determinate seasonal fluctuations of soil organic carbon and soil labile carbon in both secondary oak forest and pine plantation, but the characteristics of the seasonal fluctuations of soil organic carbon or soil labile carbon were different with different land types and different treatments, there were apparent downtrend of soil organic carbon in both oak forest and pine plantation, but the downtrend in oak forest was more significant than in pine plantation, the input and decomposition of plant litter fall had important influence on maintaining the pool size of soil organic carbon and soil labile carbon.更多还原