【作者】 方显瑞；

【导师】 谢宝元； 张志强；

【作者基本信息】 北京林业大学 ， 工程绿化， 2011， 博士

【摘要】 杨树是世界上广泛采用的人工造林树种之一,也是中国人工林面积最大的树种。研究大兴沙地杨树人工林生态系统碳交换在不同时间尺度上的动态格局及其强度特征,分析其对环境因子的响应是提高杨树人工林生态系统净生产力和进行碳汇造林等杨树人工林经营管理中首要考虑的问题之一。采用涡度相关系统、4气室Licor-8150土壤呼吸测定系统和小气候测定系统从2006-2009年对位于北京大兴区永定河沿河沙地欧美杨(欧美107,Populus×euramericana cv. "74/76")人工林生态系统的净生态系统碳交换(NEE)、生态系统呼吸(Re)、生态系统初级生产力(GEP)和土壤呼吸(Rs)以及环境气象因子进行了连续动态测定,分析研究表明：(1)2006～2009年,生态系统在生长季的半小时尺度上的能量闭合度分别为0.81、0.77、0.78和0.73,日尺度上的能量闭合度分别为0.95、0.87、0.92和0.81,能量闭合程度较好。(2)经过分离量化,2006～2009年,生态系统的NEE年总量分别为-403.72、-372.74、-790.10和-563.18 gCm-2yr-1GEP年总量分别为1384.79、1319.30、1653.68和1380.05 gCm-2yr-1；Re年总量在2006～2009年分别为981.07、946.68、863.58和817.30 gCm-2yr-1；Rs年总量在2007～2009年分别为642.11、629.29和609.05gCm-2yr-1(3)2006～2009年,其NEE生长季总量分别为-590.95、-640.62、-929.41和-664.50 gCm-2yr-1；GEP生长季总量分别为1270.46、1232.91、1568.81和1278.83gCm-2yr-1；Re生长季总量分别为679.51、592.41、639.41和614.34 gCm-2yr-1。(4)四年中,生长季NEE年际变化少于年NEE的年际变化,GEP的生长季总量与年总量比例均在90%以上,Re生长季总量占其年总量的比例分别为69.26%、62.58%、74.04%和75.17%。Rs年总量与Re年总量比值在2007～2009年中分别为67.83%、72.87%和74.52%。(5)光合有效辐射(PAR)是生长季白天半小时尺度上NEE的最主要影响因子,它能够解释46.8%-67.7%的生长季白天半小时尺度上的NEE变化。(6)在半小时尺度上,Ts5是影响生长季夜间Re的最主要因子,空气平均温度(Ta)是影响非生长季夜间Re变化的最主要因子。(7)Ts5是Rs的主要影响因子；而Re相对于Rs更受到Ts5和0～20cm土壤体积含水量(vwc)耦合效应的影响,且vwc相对于Ts5更能够影响Re。更多还原

【Abstract】 Poplar is one of the most widely used afforestation species in the world, and occupies the larg-est area of plantations in China. It is critically important to determine the carbon exchange as im-pacted by environmental factors at different time scales for managing poplar plantations to improve the productivity and carbon sequestration functionality. Net ecosystem exchange (NEE), gross eco-system production (GEP), ecosystem respiration (Re) that of the carbon exchange, and meteorologi-cal factors of a Populus×euramericana cv. "74/76" plantation located on the floodplain of Yong-ding River in Daxing District, Beijing, were measured by using an eddy covariance system and a microclimate measurement system from 2006 to 2009, respectively. Furthermore, soil respiration (Rs), was measured by a4-channel soil respiration measurement system (Li-8150, Li-Cor, NE) in the poplar plantation ecosystem from 2007 to 2009. The variations of NEE, GEP, Re, Rs and their re-sponses to environmental factors were analyzed and discussed in the paper.(1) The degree of energy closure was shown a better result in the data quality. It was 0.81,0.77, 0.78 and 0.73 at half-hourly scale that compared it was 0.95,0.87,0.92 and 0.81 at daily scale in the growing seasons from 2006 to 2009, respectively.(2) Annual NEE was-403.72,-372.74,-790.10 and-563.18 gCm-2yr-1from 2006 to 2009, re-spectively, which compared to-590.95,-640.62,-929.41 and -664.50 gCm-2yr-1 for the comulated NEE during the four growing seasons. The inter-annual variation of comulated during the growing seasons was more than that of total year.(3) The comulated GEP over the four growing seasons was 1270.46,1232.91,1568.81 and 1278.83 gCm-2yr-1 from 2006 to 2009, which was part of 1384.79,1319.30,1653.68 and 1380.05 gCm-2 yr-1 over the four total years, respectively. The ratio of comulated GEP over the four growing seasons to annual GEP was more than 90% in the four years.(4) Annual Re was 981.07,946.68,863.58 and 817.30 gCm-2 yr-1, and comulated Re during the four growing seasons was 679.51,592.41,639.41 and 614.34 from 2006 to 2009, respectively. The ratio of comulated Re during the four growing seasons to annual Re was 69.26%,62.58%,74.04% and 75.71%.(5) Annual Rs was 642.11,629.29 and 609.05 gCm-2yr-1from 2007 to 2009, respectively, and the ratio of annual Rs to annual Re was 67.83%,72.87%and 74.52%in the three years,.(6) The most significant pertinence associated with NEE was PAR, which can explain about 46.8%～67.7% of the variation at half-hourly scale in daytime during the growing seasons.(7) Ts5 was the most significant factor for Re at half-hourly scale at night over the growing seasons, while in the non-growing seasons, the most significant pertinence associated with Re was Ta at night.(8) Re was serious affected by disease and insect or drought stress, but it was obsolete for Rs. Re and Rs were mainly controlled by Ts5, but Rs was more responsive to Ts5 than Re. Re was more affected by vwc than Rs.更多还原