桂东南不同密度柳杉人工林生态系统生物量及碳氮格局研究-生态学专业论文.docxVIP

II II 476.9~519.6g·kg-1 之间。平均氮素含量分别为：高密度在 0.83~13.87g·kg-1 之间、中密度在 0.76 ~13.28 g·kg-1 之间、低密度在 0.96~15.34 g·kg-1 之间。 检验得出不同密度林分与不同器官之间碳、氮含量差异均表现为极显著 （P0.01）。 （4）三种密度柳杉人工林生态系统碳储量的估算分别为高密度 371.55 t·hm-2、中密度 414.96 t·hm-2 和低密度 332.40 t·hm-2；氮储量分别为高密度 19.95 t·hm-2、中密度 22.11 t·hm-2 和低密度 17.67 t·hm-2，都表现为中密度﹥ 高密度﹥低密度。土壤 0-100cm 层的碳、氮储量均占整个生态系统的主要 部分，其中土壤碳储量占生态系统的 68.59~75.96%，土壤氮储量占生态系 统的 95.41~ 97.08%。 （5）据实验数据显示：不同含水率的土壤在实验初期，当氮源添加的 量达到一定值时，随着氮添加量的增加对土壤呼吸出现的抑制作用也逐渐 增加，而随着时间的推移，氮元素对土壤呼吸的抑制作用逐渐变成了促进 作用，最后土壤呼吸逐渐变成与空白值趋于一致。说明氮添加对土壤呼吸 的影响与其添加量与时间有关。 关键词：柳杉 密度效应 生物量模型 生物量 碳储量 氮储量 III III RESEARCH ABOUT THE CARBON AND NITROGEN PATTERN AND ECOSYSTEM BIOMASS OF CRYPTOMERIA FORTUNEI PLANTATION OF DIFFERENT DENSITY IN SOUTH EASTERN GUANG XI PROVINCE ABSTRACT In this essay，the 31 year-old Cryptomeria fortunei plantations of different density were studied in southeastern Guangxi. The biomass, productivity and allocation pattern of carbon and nitrogen storage of Cryptomeria fortunei plantations in tropical regions of South Asia is researched. Monsic layered cut method, whole root excavation and quadrant harvest method were adopted for the determination of biomasses of various forest stand-level in different density plots. The correlate data of sample trees were used to establish the regression model of different organs, and the total biomass of arbor layer. Elemental analyzer was used to determine the carbon and nitrogen content of vegetation and soil, as well as to calculate the total carbon, nitrogen reserves of forest stand. Indoor analog nitrogen source addition was applied to determine the respond of forest stand soil respiration to atmospheric nitrogen deposition. The result showed that: PAGE PAGE VI By using correlate data of sample trees and linear and nonlinear regression analysis of software, the Optimal equation of Cryptomeria fortunei plantation biomass is W=a×Db×Hc, among which the goodness of fit of regression model of the root stump and whole plant are the