Seasonal variation of CO_2 flux and its environmental factors in evergreen coniferous plantation

作     者：LIU Yunfen SONG Xia YU Guirui SUN Xiaomin WEN Xuefa CHEN Yongrui 

作者机构：Institute of Geographic Sciences and Natural Resources ResearchChinese Academy SciencesBeijing 100101China Graduate School of the Chinese Academy of SciencesBeijing 10039China 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2005年第48卷第Z1期

页      面：123-132页

学科分类：07[理学] 0713[理学-生态学] 

基　　金：the Chinese Academy of Sciences and the Ministry of Science and Technology(KZCX1-SW01 and 2002CB412500) Institute of Geographic Sciences and Natural Resources Research, CAS, the Knowledge Innovation Engineering Backbone Science Plan, respectively 

主　　题：net ecosystem exchange eddy covanance coniferous plantation red earth hilly area 

摘      要：The effects of environmental factors on carbon flux were analyzed, the spatial and temporal variation of carbon flux was studied at the two heights of 23 m and 39 m with the eddy covariance technique, and the carbon budget was evaluated for evergreen coniferous plantation in the red earth hilly area during the year 2003. The results showed that photosynthetically active radiation (PAR) and soil temperature are essential factors strongly affecting the net ecosystem exchange (NEE); in the daytime, the response of NEE to PAR shows a rectangular hyperbola trend, and in the nighttime, the significant correlation was observed between soil temperature and soil respiration which was filtered using friction velocity. This ecosystem appeared as a carbon sink along the whole year of 2003, and the carbon flux showed the obvious seasonal fluctuation and diurnal variability. The seasonal peak of NEE occurred in May and June with the daily sum about 0.61-0.67 mg · CO2 · m-2 · s-1. For the severe drought in the mid-summer, the daily sum was 0.40-0.44 mg · CO2 · m-2 · s-1 in July which was only 2/3 of that in the last two months. For the lasted drought of the year, the nadir of NEE happened in the winder with the daily sum about -0.29 to -0.35 mg · CO2 · m-2 · s-1. The sink intensity of the ecosystem was about -0.553 to -0.645 kg · Cm-2 per year in 2003.