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Photosynthate supply drives soil respiration of Fraxinus mandshurica seedlings in northeastern China： evidences from a shading and nitrogen addition experiment

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Journal of Forestry Research 2016年第6期27卷 1271-1276页

作者： Yanli Jing dexin guan Jiabing Wu Anzhi Wang Changjie Jin Fenghui Yuan Key Laboratory of Forest Ecology and Management Institute of Applied Ecology Chinese Academy of SciencesShenyang 110164 People's Republic of China University of Chinese Academy of Sciences Beijing 100049People's Republic of China

Improved understanding of the link between photosynthesis and below-ground processes is needed to better understand ecosystem carbon （C） cycling and its feedback to climate change. We conducted a short-term shading and nitrogen （N） addition experiment from June to September 2013 to investigate the effect of photosynthate supply by Manchurian Ash （Fraxinus mandshurica） seed- lings on soil respiration （SR）. Shading significantly reduced SR in early and middle growing season, but not in late growing season, leading to a decrease in mean SR by 24 % in N-unfertilized treatments. N addition increased mean SR by 42 % in un-shaded treatment. The stimulation of SR was largely attributed to accelerated autotrophic respiration by increasing photosynthesis, leaf area index and belowground biomass. Shading reduced mean SR by 32 % in N addition treatment. The strengthened shading effect on SR resulted from N addition was because of more photosynthates supply at low soil temperature. Our findings highlight the predominance of photosynthates supply in regulating the responses of C cycling to global change.

关键词： Autotrophic respiration Carbon Fertilization Shading Substrate supply

Structural Parameters of Wind Protection of Shelterbelts and Application

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Chinese Forestry Science and Technology 2005年第3期4卷 1-10页

作者： ZHU Tingyao guan dexin WU Jiabing JIN Changjie Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 P.R. China

A new structural parameter of shelterbelts, above-ground density of biomass volume, was putforward in this paper. Its practicality in managements of the shelterbelts and its physical meaning of windreduction were expounded. Analytical relations between the new parameter and often-used parameters(permeability and porosity) were deduced. An example was given to show the application of the newparameter in the management of shelterbelts.

关键词： density of biomass volume shelterbelt wind reduction coefficient permeability porosity

Effects of N Application Rates and NO_3-N to NH_4-N Ratios on Yield and Quality of Flue-cured Tobacco Planted in Black Soil

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Journal of Northeast Agricultural University(English Edition) 2006年第2期13卷 121-124页

作者： SHAN dexin guan Shengyu SHAN Dechen XU Jinggang Resources and Environmental Sciences College Northeast Agricultural University Harbin Heilongjiang 150030 PRC

A field experiment about effects of nitrogen application rates and different NO3-N to NH4-N ratios on agronomic, chemical and biological characteristics as well as yield and quality of flue-cured tobacco grown in a black soil was conducted from 2004 to 2005 in Heilongjiang Province. The results showed that the nitrogen application rates at 45 kg·hm^-2 with the ratio of 75% NO3-N to 25% NH4-N resulted in the highest potassium and reducing sugar contents in the flue-cured tobacco leaving with the highest quality grade and value. It is recommended that this ni- trogen application rate and NO3-N to NH4-N ratio should be widely applied on flue-cured tobacco grown in the black soil in Heilongjiang Province.

关键词： N application rate NO3-N to NH4-N ratio flue-cured tobacco black soil

Seasonal and annual variation of CO_2 flux above a broad-leaved Korean pine mixed forest

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Science China Earth Sciences 2006年第S2期49卷 63-73页

作者： ZHANG Junhui, YU Guirui, HAN Shijie, guan dexin & SUN Xiaomin Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China 1. Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 China2. Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China

Long-term measurement of carbon metabolism of old-growth forests is critical to predict their behaviors and to reduce the uncertainties of carbon accounting under changing climate. Eddy covariance technology was applied to investigate the long-term carbon exchange over a 200 year-old Chinese broad-leaved Korean pine mixed forest in the Changbai Mountains (128°28’E and 42°24’N, Jilin Province, P. R. China) since August 2002. On the data obtained with open-path eddy covariance system and CO2 profile measurement system from Jan. 2003 to Dec. 2004, this paper reports (i) annual and seasonal variation of FNEE, FGPP and Re; (ii) regulation of environmental factors on phase and amplitude of ecosystem CO2 uptake and release Corrections due to storage and friction velocity were applied to the eddy carbon flux. Lal and soil temperature determined the seasonal and annual dynamics of FGPP and RE separately. VPD and air temperature regulated ecosystem photosynthesis at finer scales in growing seasons. Water condition at the root zone exerted a significant influence on ecosystem maintenance carbon metabolism of this forest in winter. The forest was a net sink of atmospheric CO2 and sequestered -449 g C·m-2 during the study period; -278 and -171 gC·m-2 for 2003 and 2004 respectively. FGPP and FRE over 2003 and 2004 were -1332, -1294 g C·m-2. and 1054, 1124 g C·m-2 respectively. This study shows that old-growth forest can be a strong net carbon sink of atmospheric CO2. There was significant seasonal and annual variation in carbon metabolism. In winter, there was weak photosynthesis while the ecosystem emitted CO2. Carbon exchanges were active in spring and fall but contributed little to carbon sequestration on an annual scale. The summer is the most significant season as far as ecosystem carbon balance is concerned. The 90 days of summer contributed 66.9, 68.9% of FGPp, and 60.4, 62.1% of RE of the entire year.

关键词： old-growth forest eddy-covariance carbon metabolism seasonal and annual dynamics

Estimate of productivity in ecosystem of the broad-leaved Korean pine mixed forest in Changbai Mountain

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Science China Earth Sciences 2006年第S2期49卷 74-88页

作者： WANG Miao, guan dexin, WANG Yuesi, HAO Zhanqing &LIU Yaqin Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China Eastern Liaoning University, Dandong 118003, China Chinese Acad Sci Inst Appl Ecol Shenyang 110016 Peoples R China Chinese Acad Sci Inst Atmospher Phys Beijing 100029 Peoples R China Eastern Liaoning Univ Dandong 118003 Peoples R China

We measured soil, stem and branch respiration of trees and shrubs, foliage photosynthesis and respiration in ecosystem of the needle and broad-leaved Korean pine forest in Changbai Mountain by LI-6400 CO2 analysis system. Measurement of forest microclimate was conducted simultaneously and a model was found for the relationship of soil, stem, leaf and climate factors. CO2 flux of different components in ecosystem of the broad-leaved Korean pine forest was estimated based on vegetation characteristics. The net ecosystem exchange was measured by eddy covariance technique. And we studied the effect of temperature and photosynthetic active radiation on ecosystem CO2 flux. Through analysis we found that the net ecosystem exchange was affected mainly by soil respiration and leaf photosynthesis. Annual net ecosystem exchange ranged from a minimum of about -4.671μmol·m-2·s-1 to a maximum of 13.80μmol·m-2·s-1, mean net ecosystem exchange of CO2 flux was -2.0μmol·m-2·s-1 and 3.9μmol·m-2·s-1 in winter and summer respectively (mean value during 24 h). Primary productivity of tree, shrub and herbage contributed about 89.7%, 3.5% and 6.8% to the gross primary productivity of the broad-leaved Korean pine forest respectively. Soil respiration contributed about 69.7% CO2 to the broad-leaved Korean pine forest ecosystem, comprising about 15.2% from tree leaves and 15.1% from branches. The net ecosystem exchange in growing season and non-growing season contributed 56.8% and 43.2% to the annual CO2 efflux respectively. The ratio of autotrophic respiration to gross primary productivity (Ra:GPP) was 0.52 (NPP:GPP=0.48). Annual carbon accumulation underground accounted for 52% of the gross primary productivity, and soil respiration contributed 60% to gross primary productivity. The NPP of the needle and broad-leaved Korean pine forest was 769.3 gC·m-2·a-1. The net ecosystem exchange of this forest ecosystem (NEE) was 229.51 gC·m-2·a-1. The NEE of this forest ecosystem acquired by eddy cova

关键词： carbon balance eddy covariance technique primary productivity net ecosystem exchange of CO2 flux the broad-leaved Korean pine forest.

A Numerical Scheme to Obtain the RCS of Serrated Targets Using CG-FFT

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Journal of Systems Engineering and Electronics 1997年第2期8卷 24-32页

作者： Wang Baofa & guan dexin(Dept. of Electrical Engineering and Computer Science,Beijing University of Aeronautics and Astronautics, 100083, P. R. China) Dept. of Electrical Engineering and Computer Science Beijing University of Aeronautics and Astronautics 100083 P. R. China

A numerical scheme to obtain the radar cross section (RCS) of scattering bodies of resonant size with serrated structure is described. The RCS is obtained by solving the electric field integral equation (EFIE) using the conjugate gradientfast Fourier transform method (CGFFT). With this combination, the computational time required to solve scattering problems of resonant size bodies is much less than the time required by the ordinary conjugate gradient method and the method of moments. On the other hand, since the spatial derivatives are replaced with simple multilocations in the transformed domain. Some of the computational difficulties present in the ordinary conjugate gradient method and the method of moments do not exist here. The choice of a suitable set of basis and testing functions to discretize the EFIE leads to obtain a very accurate efficient CGFFT procedure. Finally, since the method is iterative, it is possible to know the accuracy in a problem solution.The numerical results also show that conducting serrated structure can be applied to reduce the RCS values of straight wedge so long as the shape and size are selected properly.

关键词： Radar cross section Conjugate gradient Fast Fourier transform.

Photosynthetic characteristics of dominant tree species and canopy in the broadleaved Korean pine forest of Changbai Mountains

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Science China Earth Sciences 2006年第S2期49卷 89-98页

作者： WU Jiabing, guan dexin, SUN Xiaomin, ZHANG Mi, SHI Tingting, HAN Shijie & JIN Changjie Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China Graduate University of the Chinese Academy of Sciences, Beijing 100049, China Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China Chinese Acad Sci Inst Appl Ecol Shenyang 110016 Peoples R China Grad Univ Chinese Acad Sci Beijing 100049 Peoples R China Chinese Acad Sci Inst Geog Sci & Nat Resources Res Beijing 100101 Peoples R China

Based on the light-photosynthesis response measurement at leaf level, combined with over- and under-canopy eddy covariance measurements, research on photosynthetic characteristics of single trees and forest canopy was conducted. The relationship between light intensity and photo-synthetic rates for leaves and canopy can be well fitted by a non-rectangular hyperbola model. Mongolian oak presented a high light compensation point, Lcp (28μmol·m-2·s-1), a light saturation point Lsp (>1800μmol·m-2·s-1), and a maximal net photosynthetic rate Pmax (9.96μmol·m-2·s-1), which suggest that it is a typical heliophilous plant. Mono maple presented the highest apparent quantum efficiencyα(0.066) but the lowest, Lcp (16μmol·m-2·s-1), Lsp (=800μmol·m-2·s-1), and Pmax (4.51μmol·m-2·s-1), which suggest that it is heliophilous plant. Korean pine showed the lowestαvalue but a higher Pmax, which suggest that it is a semi-heliophilous plant. At the canopy level, the values of both or and Pmax approached the upper limit of reported values in temperate forests, while Lcp was within the lower limit. Canopy photosynthetic characteristics were well consistent with those of leaves. Both showed a high ability to photosynthesize. However, environmental stresses, especially high vapor pressure deficits, could significantly reduce the photosynthetic ability of leaves and canopy.

关键词： photosynthesis light response curve broadleaved Korean pine forest eddy covariance method.

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长白山阔叶红松林降雨截留量的估算

应用生态学报 2006年第8期17卷 1403-1407页

作者：王安志裴铁璠金昌杰关德新中国科学院沈阳应用生态研究所沈阳110016

林冠截留降雨过程是森林流域水分循环的重要组成部分，以往的研究多为1次或多次降雨量与截留量的关系，很少考虑雨强和树木特征．文中利用林冠截留降雨半经验半理论模型，以雨强和叶面积指数为模型输入，林冠湿润程度为参数，结合Penman... 详细信息

林冠截留降雨过程是森林流域水分循环的重要组成部分，以往的研究多为1次或多次降雨量与截留量的关系，很少考虑雨强和树木特征．文中利用林冠截留降雨半经验半理论模型，以雨强和叶面积指数为模型输入，林冠湿润程度为参数，结合Penman—Monteith公式，有效地模拟了长白山阔叶红松林次降雨的截留过程和2004年5—9月的林冠截留总量．结果表明，研究期间的林冠截留总量为39．96mm，占降雨总量的10．2％，与实测资料吻合．根据模拟结果，探讨了不同时间尺度上截留量与降雨量之间的关系，随着时间尺度的增大，截留量与降雨量的相关关系趋于明显．

关键词：截留分配降雨模型雨强叶面积指数

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接收机设计

电子测量技术 2005年第5期28卷 22-22,28页

作者：陈昊关德新北京航空航天大学

为在公共通信网络无法覆盖的地区实现可靠通信,设计采用二次变频的短波接收机,将其与普通的商用电台组成通信系统,可以获得很高的通信质量,同时该接收机具有体积小和功耗低的特点,具有较好的实用价值。

关键词：二次变频灵敏度短波接收机设计可靠通信通信网络通信系统通信质量实用价值体积小