五种温带森林非生长季土壤呼吸的研究
|
摘要
以往的土壤呼吸(Rs)研究绝大多数集中于生长季,而对非生长季Rs的研究很少。冬季Rs是生态系统呼吸中的重要组成部分,并且能显著地影响碳收支。春季土壤解冻过程是中高纬度地区森林生态系统Rs年内变化的一个关键时期,但此期间Rs的时间动态规律及其控制机理尚不清楚。本研究以我国东北东部5种温带森林(蒙古栎(Quercus mongolica)林、杨桦(Populus davidiana—Betula platyphylla)林、硬阔叶林、红松(Pinus koraiensis)林和落叶松(Larix gmelinii)林)为研究对象,采用静态箱—气相色谱法测定非生长季时期Rs动态及其相关的环境因子。主要研究结果如下：
冬季不同林型的Rs变化没有明显的规律,基本上在冬季末期达到最大值,其中只有硬阔叶林的Rs与土壤温度的变化一致,其余林型的Rs变化格局与土壤温度的关联性不大。与生长季相比,冬季的Rs与土壤温度和含水量的之间的关系不是很紧密(R2=0.266—0.422)。Rs年通量从大到小依次为：硬阔叶林2114.90 g·m-2yr-1；杨桦林1989.66 g·m-2yr-1；蒙古栎林1860.88 g·m-2yr-1；红松林1435.56 g·m-2yr-1和落叶松林1934.59 g·m-2yr-1。各自对应的冬季Rs通量在年通量中所占的比例分别为：9.63%；10.19%；13.08%；12.78%和10.13%。冬季时期不同林型Rs的Q10值从大到小依次为：硬阔叶林12.5；落叶松林10.5；杨桦林6.8；红松林4.6和蒙古栎林2.4。除了蒙古栎林和红松林冬季和全年的Q10值比较接近外,其余林型的Q10值在冬季时普遍大于生长季的。
在土壤解冻过程中,Rs受林型、解冻时期及其交互作用的显著影响。红松林、落叶松林、硬阔叶林、杨桦林和蒙古栎林的Rs变化范围依次为：10.0—196.0 mg·m-2·h-1,5.8—217.1 mg·m-2·h-1,9.7—382.1 mg·m-2·h-1,15.8—269.0 mg·m-2·h-1和35.9—262.5mg·m-2·h-1。Rs的平均值随着解冻的进程而增大,其变化趋势大致与土壤温度的变化相吻合。土壤温度极显著地影响Rs(R2=0.46—0.77),而土壤含水量对Rs的影响则因林型和土壤深度而异。5种林型的土壤呼吸温度系数(Q10)依次为：落叶松林10.9,硬阔叶林7.1,红松林6.5,杨桦林4.3和蒙古栎林2.3。进一步的研究应该集中研究非生长季时期Rs的控制机制,尤其是Rs与土壤微生物种群动态及其活性之间的关系。
Most previous studies on soil respiration (Rs) are for growing seasons, while few for non-growing seasons. Winter CO2 efflux from soils is a significant component of annual carbon budges and can greatly determine carbon balance of ecosystems. Spring soil thawing period is critical in the intra—annual dynamics of Rs in mid—and high latitudes forest ecosystems, in which the frequently occurring alternate freezing and thawing events strongly influence the availability and dynamics of soil carbon and nutrients. However the temporal changes of Rs and involved mechanisms are poorly understood. Especially in situ measurements of Rs in spring soil thawing process are needed. In this study, a static closed chamber—gas chromatograph technique was used to measure the Rs and related biophysical factors in representative temperate forests of Northeast China during the non-growing season. The experimental design included five forest types, three random plots in each forest type, and three randomly installed static chambers in each plot. The forests were oak forest dominated by Quercus mongolica, poplar—birch forest dominated by Populus davidiana and Betula platyphylla, hardwood forest dominated by Fraxinus mandshurica, Juglans mandshurica and Phellodendron amurense, Korean pine (Pinus koraiensis) plantation, and Dahurian larch (Larix gmelinii) plantation. The results showed:
During winter period, there were no obvious temporal trends for the Rs. We found the highest CO2 fluxes in late winter and patterns of Rs for different forest types were independent of soil temperature except for hardwood forest. Compared with growing seasons, soil temperature and water content did not significantly influence the Rs (R2=0.266—0.422) The annual fluxes for the hardwood, poplar—birch, and oak, pine and larch forests were 2114.90 g·m-2yr-1,1989.66 g·m-2yr-1,1860.88 g·m-2yr-1,1435.56g·m-2yr-1, and 1934.59 g·m-2yr-1,respectively; the ratio of winter fluxes for those were 9.63%,10.19%,13.08%,12.78%, and 10.13%, correspondingly. In winter, the temperature coefficients of Rs (Q10) for the hardwood, larch, poplar—birch, pine, and oak forests were 12.5,10.5,6.8,4.6, and 2.4, respectively. Q10 during winter time were much higher than those in the whole year except for pine and oak forests.
During the soil thawing period, the forest types, thawing periods and their interaction significantly affected the Rs. The Rs for the pine, larch, hardwood, poplar—birch, and oak forests varied from 10.0—196.0 mg·m-2·h-1,5.8—217.1 mg·m-2·h-1,9.7—382.1 mg·m-2·h-1, 15.8—269.0 mg·m-2·h-1, and 35.9—262.5 mg·m-2·h-1, respectively. The mean Rs, T2 and W2 differed significantly among the five forest types(P<0.001). The Rs for broadleaved forests were generally higher than coniferous plantations. The mean values of RS increased as the soil thawing proceeded, and were largely consistent with the changes in soil temperature. Soil temperature significantly influenced the Rs, while the effect of soil water content on the Rs varied with forest types and soil depths. The Rs was significantly affected by W2 for all forests except for the oak forest. The statistical models of the Rs against T2 and W2 explained 60%—77% of the variability in the Rs measurements. The Q10 during the spring soil thawing period were much higher than those in the growing season, and changed with forest types. The Q10 for the larch, hardwood, pine, poplar—birch, and oak forests were 10.9,7.1,6.5,4.3, and 2.3, respectively. Further studies should focus on the mechanisms controlling Rs in the in situ soil, especially on temporal dynamics of soil microbial population in non-growing seasons and the relationship between soil respiration and soil microbial activity and composition.
冬季不同林型的Rs变化没有明显的规律,基本上在冬季末期达到最大值,其中只有硬阔叶林的Rs与土壤温度的变化一致,其余林型的Rs变化格局与土壤温度的关联性不大。与生长季相比,冬季的Rs与土壤温度和含水量的之间的关系不是很紧密(R2=0.266—0.422)。Rs年通量从大到小依次为：硬阔叶林2114.90 g·m-2yr-1；杨桦林1989.66 g·m-2yr-1；蒙古栎林1860.88 g·m-2yr-1；红松林1435.56 g·m-2yr-1和落叶松林1934.59 g·m-2yr-1。各自对应的冬季Rs通量在年通量中所占的比例分别为：9.63%；10.19%；13.08%；12.78%和10.13%。冬季时期不同林型Rs的Q10值从大到小依次为：硬阔叶林12.5；落叶松林10.5；杨桦林6.8；红松林4.6和蒙古栎林2.4。除了蒙古栎林和红松林冬季和全年的Q10值比较接近外,其余林型的Q10值在冬季时普遍大于生长季的。
在土壤解冻过程中,Rs受林型、解冻时期及其交互作用的显著影响。红松林、落叶松林、硬阔叶林、杨桦林和蒙古栎林的Rs变化范围依次为：10.0—196.0 mg·m-2·h-1,5.8—217.1 mg·m-2·h-1,9.7—382.1 mg·m-2·h-1,15.8—269.0 mg·m-2·h-1和35.9—262.5mg·m-2·h-1。Rs的平均值随着解冻的进程而增大,其变化趋势大致与土壤温度的变化相吻合。土壤温度极显著地影响Rs(R2=0.46—0.77),而土壤含水量对Rs的影响则因林型和土壤深度而异。5种林型的土壤呼吸温度系数(Q10)依次为：落叶松林10.9,硬阔叶林7.1,红松林6.5,杨桦林4.3和蒙古栎林2.3。进一步的研究应该集中研究非生长季时期Rs的控制机制,尤其是Rs与土壤微生物种群动态及其活性之间的关系。
Most previous studies on soil respiration (Rs) are for growing seasons, while few for non-growing seasons. Winter CO2 efflux from soils is a significant component of annual carbon budges and can greatly determine carbon balance of ecosystems. Spring soil thawing period is critical in the intra—annual dynamics of Rs in mid—and high latitudes forest ecosystems, in which the frequently occurring alternate freezing and thawing events strongly influence the availability and dynamics of soil carbon and nutrients. However the temporal changes of Rs and involved mechanisms are poorly understood. Especially in situ measurements of Rs in spring soil thawing process are needed. In this study, a static closed chamber—gas chromatograph technique was used to measure the Rs and related biophysical factors in representative temperate forests of Northeast China during the non-growing season. The experimental design included five forest types, three random plots in each forest type, and three randomly installed static chambers in each plot. The forests were oak forest dominated by Quercus mongolica, poplar—birch forest dominated by Populus davidiana and Betula platyphylla, hardwood forest dominated by Fraxinus mandshurica, Juglans mandshurica and Phellodendron amurense, Korean pine (Pinus koraiensis) plantation, and Dahurian larch (Larix gmelinii) plantation. The results showed:
During winter period, there were no obvious temporal trends for the Rs. We found the highest CO2 fluxes in late winter and patterns of Rs for different forest types were independent of soil temperature except for hardwood forest. Compared with growing seasons, soil temperature and water content did not significantly influence the Rs (R2=0.266—0.422) The annual fluxes for the hardwood, poplar—birch, and oak, pine and larch forests were 2114.90 g·m-2yr-1,1989.66 g·m-2yr-1,1860.88 g·m-2yr-1,1435.56g·m-2yr-1, and 1934.59 g·m-2yr-1,respectively; the ratio of winter fluxes for those were 9.63%,10.19%,13.08%,12.78%, and 10.13%, correspondingly. In winter, the temperature coefficients of Rs (Q10) for the hardwood, larch, poplar—birch, pine, and oak forests were 12.5,10.5,6.8,4.6, and 2.4, respectively. Q10 during winter time were much higher than those in the whole year except for pine and oak forests.
During the soil thawing period, the forest types, thawing periods and their interaction significantly affected the Rs. The Rs for the pine, larch, hardwood, poplar—birch, and oak forests varied from 10.0—196.0 mg·m-2·h-1,5.8—217.1 mg·m-2·h-1,9.7—382.1 mg·m-2·h-1, 15.8—269.0 mg·m-2·h-1, and 35.9—262.5 mg·m-2·h-1, respectively. The mean Rs, T2 and W2 differed significantly among the five forest types(P<0.001). The Rs for broadleaved forests were generally higher than coniferous plantations. The mean values of RS increased as the soil thawing proceeded, and were largely consistent with the changes in soil temperature. Soil temperature significantly influenced the Rs, while the effect of soil water content on the Rs varied with forest types and soil depths. The Rs was significantly affected by W2 for all forests except for the oak forest. The statistical models of the Rs against T2 and W2 explained 60%—77% of the variability in the Rs measurements. The Q10 during the spring soil thawing period were much higher than those in the growing season, and changed with forest types. The Q10 for the larch, hardwood, pine, poplar—birch, and oak forests were 10.9,7.1,6.5,4.3, and 2.3, respectively. Further studies should focus on the mechanisms controlling Rs in the in situ soil, especially on temporal dynamics of soil microbial population in non-growing seasons and the relationship between soil respiration and soil microbial activity and composition.
引文
[1]Schlesinger WH. Biogeochemistry:an analysis of global change.2nd Edn. Academic Press, San Diego,1997,588.
[2]Marland G, Bode TA, Andres RJ. Global, regional and national CO2 emission, in:Trends: A Compendium of data on global change. Carbon dioxide information analysis center. Oak Rige National Laboratory, US Department of Energy, Oak Rige,Tennessee,2001.
[3]Bouwmann AF, Germon JC. Special issue:soils and climate change:introduction. Biology and Fertility of Soils,1998,27:219.
[4]Singh JS, Gupta SR. Plant decomposition and soil respiration in terrestrial ecosystems. The Botanical Review,1977,43:449-528.
[5]王娓,汪涛,彭书时,方精云.冬季土壤呼吸：不可忽视的地气CO2交换过程.植物生态学报,2007,31(3)：394-402.
[6]Monson RK, Sparks JP, Rosenstiel TN, et al. Climatic influences on net ecosystem CO2 exchange during the transition from wintertime carbon source to springtime carbon sink in a high-elevation, subalpine forest. Oecologia,2005,146:130-147.
[7]Hubbard RM, Ryan MG, Elder K, et al. Seasonal patterns in soil surface CO2 flux under snow cover in 50 and 300 year old subalpine forests. Biogeochemistry,2005,73:93-107.
[8]Grogan P, Michelsen A, Ambus P, et al. Freeze-thaw regime effects on carbon and nitrogen dynamics in sub-arctic heath tundra mesocosms. Soil Biology & Biochemistry, 2004,36(4):641-654.
[9]Herrmann A, Witter E. Sources of C and N contributing to the flush in mineralization upon freeze-thaw cycles in soils. Soil Biology & Biochemistry,2002,34(10):1495-1505.
[10]Schimel JP, Clein JS. Microbial response to freeze-thaw cycles in tundra and taiga soils. Soil Biology &Biochemistry,1996,28(8):1061-1066.
[11]Campbell JL, Mitchell MJ, Groffman PM, et al. Winter in northeastern North America:A critical period for ecological processes. Frontiers in Ecology and the Environment,2005, 3(6):314-322.
[12]Clein JS, Schimel JP. Microbial activity of tundra and taiga soils at subzero temperatures. Soil Biology &Biochemistry,1995,27(9):1231-1234.
[13]Edwards KA, McCulloch J, Kershaw GP, et al. Soil microbial and nutrient dynamics in a wet arctic sedge meadow in late winter and early spring. Soil Biology & Biochemistry, 2006,38(9):2843-2851.
[14]Sommerfeld RA, Massman WJ, Musselman RC. Diffusional flux of CO2 through snow: spatial and temporal variability among alpine-subapline sites. Global Biogeochemical Cycles,1996,10:473-482.
[15]McDowell NG, Marshall JD, Hooker TD. Estimating CO2 flux from snowpacks at three sites in the Rocky Mountains. Tree Physiology,2005,20:745-753.
[16]Suzuki S, Ishizuka S, Kitamura K. Continuous estimation of winter carbon dioxide efflux from the snow surface in a deciduous broadleaf forest. Journal of Geophysical Research. 2006, 111,D17101,doi:10.1029/2005 JD006595.
[17]Zimov SA, Davidov SP, Voropaev YV, et al. Siberian CO2 efflux in winter as CO2 source and cause of seasonality in atmospheric CO2. Climatic Change,1996,33:111-120.
[18]Winston GC, Stephens BB, Trumbore SE. Winter CO2 fluxes in a boreal forest. J. Geophys. Res.1997,102:28795-28804.
[19]Mariko S, Nishimura N, Mo W, et al. Winter CO2 flux from soil and snow surfaces in a cooltemperate deciduous forest, Japan. Ecol. Res.2000,15:363-372.
[20]Mast MA, Wickland KP, Striegl RT, et al. Winter fluxes of CO2 and CH4 from subalpine soils in Rocky Mountain National Park, Colorado. Global Biogeochem. Cycles,1998,12 (4):607-620.
[21]Vogel JG, Valentine DW, Ruess RW. Soil and root respiration in mature Alaskan black spruce forests that vary in soil organic matter decomposition rates. Can. J. Forest Res. 2005,35,161-174.
[22]Brooks PD, McKnight D, Elder K. Carbon limitation of soil respiration under winter snowpacks:potential feedbacks between growing season and winter carbon fluxes. Global Change Biology,2005,11,231-238.
[23]Matzner E, Borken W. Do freeze-thaw events enhance C and N losses from soils of different ecosystems? A review. European Journal of Soil Science,2008,59(2):274-284.
[24]Groffman P M, Hardy J P, Driscoll C T, et al. Snow depth, soil freezing, and fluxes of carbon dioxide, nitrous oxide and methane in a northern hardwood forest. Global Change Biology,2006,12(9):1748-1760.
[25]Muhr J, Borken W, Matzner E. Effects of soil frost on soil respiration and its radiocarbon signature in a Norway spruce forest soil. Global Change Biology,2009,15(4):782-793.
[26]Dorsch P, Palojarvi A, Mommertz S. Overwinter greenhouse gas fluxes in two contrasting agricultural habitats. Nutrient Cycling in Agroecosystems,2004,70:117-133
[27]Prieme A, Christensen S. Natural perturbations, dryingwetting and freezing-thawing cycles, and the emission of nitrous oxide, carbon dioxide and methane from farmed organic soils. Soil Biology & Biochemistry,2001,33:2083-2091.
[28]Monson RK, Lipson DL, Burns SP, et al. Winter forest soil respiration controlled by climate and microbial community composition. Nature,2006,439:711-714.
[29]Elberling B, Brandt KK. Uncoupling of microbial CO2 production and release in frozen soil and its implications for field studies of arctic C cycling. Soil Biology & Biochemistry, 2003,35(2):263-272.
[30]Larsen KS, Jonasson S, Michelsen A.. Repeated freezethaw cycles and their effects on biological processes in two arctic ecosystem types. Applied Soil Ecology,2002,21:187-195.
[31]Dixon RK, Brown S, Houghton RA. Carbon pools and flux of global forest ecosystems. Science,1994,263:185-190.
[32]Sommerfeld RA, Moiser AR, Musselman RC. CO2, CH4, and N2O flux through a Wyoming snowpack and implications for global budgets. Nature,1993,361:140-142.
[33]Brooks PD, Schmidt SK, Williams MW. Winter production of CO2 and N2O from alpine tundra:environmental controls and relationship to inter-system C and N fluxes. Oecologia, 1997,110:403-413.
[34]Brooks PD,Williams MW, Schmidt SK. Microbial activity under alpine snowpacks, Niwot Ridge, Colorado. Biogeochemistry,1996,32:93-113.
[35]Schadt CW, Martin AP, Lipson DL, et al. Seasonal dynamics of previously unknown fungal lineages in tundra soil. Science,2003,301:1359-1361.
[36]Schindlbacher A, Zechmeister-Boltenstern S, Glatzel G, et al. Winter soil respiration from an Austrian mountain forest. Agricultural and Forest Meteorology,2007,146:205-215.
[37]Fang C, Moncrieff JB. The Dependence of Soil CO2 Efflux on Temperature. Soil Biology and Biochemistry,2001,33:155-165.
[38]王庆丰,王传宽,谭立何.移栽自不同纬度的落叶松(Larix gmelinii Rupr.)林的春季土壤呼吸.生态学报,2008,28(5)：1883-1892.
[39]Raich JW, Schlesinger WH. The global carbon dioxide efflux in soil respiration and its relationship to vegetation and climate. Tellus,1992,44:81-90.
[40]Fung IY, Tucker CJ, Prentice KC. Application of advanced very high resolution vegetation index to study atmosphere-biosphere exchange of CO2.Journal of Geophysical Research, 1987,92:299-301
[41]Kicklighter DW. Aspects of spatial and temporal aggregation in estimating regional carbon dioxide fluxes from temperate forest soils. Journal of Geophysical Research,1994,99: 1303-1315.
[42]Jones CD, Cox P, Huntingford C. Uncertainty in climate carbon cycle projections associated with the sensitivity of soil respiration to temperature. Tellus,2003,55B:642-648.
[43]Kirschbaum MUF. Will changes in soil organic carbon act as a positive or negative feedback on global warming? Biogeochemistry,2000,48:21-51.
[44]Davidson EA, Janssens IA, Luo YQ. On the variability of respiration of respiration in terrestrial ecosystems:moving beyond Q10. Global Change Biology,2006,12:154-164.
[45]Mikan C, Schimel J, Doyle A. Temperature controls of microbial respiration above and below freezing in Arctic tundra soils. Soil Biology & Biochemistry,2002,34:1785-1795.
[46]Davidson E A, Belk E, Boone R D. Soil water content and temperature as independent or confounded factors controlling soil respiration in a temperate mixed hardwood forest. Global Change Biology,1998,4(2):217-227.
[47]Fahnestock JT, Jones MH, Brooks PD. Winter and early spring CO2 efflux from tundra communities of northern Alaska. Journal of Geophysical Research Atmosphere,1998,103: 29023-29027.
[48]Koponen HT, Jaakkola T, Keinanen-Toivola MM, et al. Microbial communities, biomass, and activities in soils as affected by freeze thaw cycles. Soil Biology & Biochemistry, 2006,38(7):1861-1871.
[49]Lipson DA, Schmidt SK, Monson RK. Carbon availability and temperature control the post-snowmelt decline in alpine soil microbial biomass. Soil Biology & Biochemistry, 2000,32(4):441-448.
[50]Christensen S, Tiedje JM. Brief and vigorous N2O production by soil at spring thaw. Journal of Soil Science,1990,41:1-4.
[51]Paul EA, Ladd JN. Soil Biochemistry. Marcel Dekker. New York,1981.Vol.5
[52]Clein JS, Schimel JP. Reduction in microbial activity in birch litter due to drying and rewetting events. Soil Biology & Biochemistry,1994,26(3):403-406.
[53]Deluca TH, Keeney DR, Mccarty GW. Effect of freeze-thaw events on mineralization of soil nitrogen.Biology and fertility of soils,1992,14(2):116-120.
[54]Skogland T, Lomeland S, Goksoyr J. Respiratory burst afterfreezing and thawing of soil: experiments with soil bacteria.Soil Biol.Biochem.,1988,20(6):851-856.
[55]Zsolnay A. Dissolved organic matter:artifacts, definitions,and functions. Geoderma, 2003,113:187-209.
[56]Ellert BH, Gregorich EG. Management induced changes in the actively cycling fractions of soil organic matter. In:Mcfee WW, Kelly J M. eds. Carbon Forms and Functions in Forest Soils. Wisconsin, Madison, USA:Soil Science Society of America, Inc.,1995, 119-138.
[57]Wang FL, Bettany JR. Influence of freeze-thaw and flooding on the loss of soluble organic carbon and carbon dioxide from soil. J.Environ.Qual.,1993,22:709-714.
[58]Scott-Denton LE, Rosenstiel TN, Monson RK. Differential controls by climate and substrate over the heterotrophic and rhizospheric components of soil respiration. Global Change Biology,2006,12:205-216.
[59]Winston GC, Stephens BB, Sundquist ET, et al. Seasonal variability in CO2 transport through snow in a boreal forest. In:Tonnessen KA, Williams MW, Tranter M (Eds.), Biogeochemistry of Seasonally Snow-Covered Catchements. IAHS Publication,1995, pp. 61-70.
[60]Kurganova I, de Gerenyu YL, Rozanova L, et al. Annual and seasonal CO2 fluxes from Russian southern taiga soils. Tellus,2003,55B:338-344.
[61]Massman WJ, Sommerfeld RA, Zeller K. CO2 flux through a Wyoming seasonal snowpack:diffusional and pressure pumping effects. In:Hudnell L, Rochelle S eds. Biogeochemistry of Snow-Covered Catchments. International Association of Hydrological Sciences, Wallingford, UK,71-79.
[62]Wang CK. Biomass allometric equations for 10 co-occurring tree species in Chinese temperate forests. Forest Ecology and Management,2006,222:9-16.
[63]Schlesinger WH. Carbon balance in terrestrial detritus. Annual Review of Ecology and Systematics,1977,8:51-81.
[64]Likens GE. A long-term record of ice-cover for Mirror Lake, NH:effects of global warming? Verhandlunden der internationale Vereinigung fu" r theoretische und angewandte Limnologie,2000,27:2765-2769.
[65]Schwartz MD, Reiter BE. Changes in North American spring. International Journal of Climatology,2000,20:929-932.
[66]Dye DG. Variability and trends in the annual snow-cover cycle in Northern Hemisphere land areas,1972-2000. Hydrological Processes,2002,16:305-3077.
[67]Hodgkins GA, Dudley RW, Huntington TG. Changes in the timing of high river flows in New England over the 20th century. Journal of Hydrology,2003,278:244-252.
[68]Wolfe DW, Schwartz MD, Lakso AN, et al. Climate change and shifts in spring phenology of three horticultural woody perennials in northeastern USA. International Journal of Biometeorology,2005,49:303-309.
[69]Williams MW, Brooks PD, Seastedt T. Nitrogen and carbon soil dynamics in response to climate change in a high-elevation ecosystem in the Rocky Mountains, USA. Arctic and Alpine Research,1998,30:26-30.
[70]Murdoch PS, Burns DA, Lawrence GB. Relation of climate change to the acidification of surface waters by nitrogen deposition. Environmental Science and Technology,1998,32: 1642-1647.
[71]Mitchell MJ, Driscoll CT, Kahl JS, et al. Climatic control of nitrate loss from forested watersheds in the northeast United States. Environmental Science and Technology,1996, 30:2609-2612.
[72]Groffman PM, Driscoll CT, Fahey TJ, et al. Colder soils in a warmer world:a snow manipulation study in a northern hardwood forest ecosystem. Biogeochemistry,2001,56: 135-150.
[73]Schimel JP, Bilbrough C, Welker JA. Increased snow depth affects microbial activity and nitrogen mineralization in two Arctic tundra communities. Soil Biology and Biochemistry, 2004,36:217-227.
[74]Valentini R, Matteucci G, Dolman AJ, et al. Respiration as the main determinant of carbon balance in European forests. Nature,2000,404:861-865.
[75]Wang CK, Bond-Lamberty B, Gower ST. Soil surface CO2 flux in a boreal black spruce fire chronosequence. Journal of Geophysical Research-Atmospheres,2002,108(D3):art no.8224.
[76]Xu M, Qi Y. Soil-surface CO2 efflux and its spatial and temporal variations in a young ponderosa pine plantation in northern California. Global Change Biology,2001,7(6):667-677.
[77]Schmidt SK, Wilson KL, Monson RK, et al. Exponential growth of "snow molds" at sub-zero temperatures:an explanation for high beneath-snow respiration rates and Q10 values. Biogeochemistry,2009,95(1):13-21.
[78]Schlesinger WH, Andrews JA. Soil respiration and the global carbon cycle. Biogeochemistry,2000,48(1):7-20.
[79]Raich JW, Potter CS. Global patterns of carbon dioxide emissions from soils. Global Biochemical Cycles,1995,9(1):23-36.
[80]Henry HAL. Soil freeze-thaw cycle experiments:trends, methodological weaknesses and suggested improvements. Soil Biology & Biochemistry,2007,39(5):977-986.
[81]Raich JW, Tufekcioglu A. Vegetation and soil respiration:Correlations and controls. Biogeochemistry,2000,48(1):71-90.
[82]Goldberg SD, Muhr J, Borken W, Gebauer G. Fluxes of climate-relevant trace gases between a Norway spruce forest soil and atmosphere during repeated freeze-thaw cycles in mesocosms. Journal of Plant Nutrition and Soil Science,2008,171(5):729-739.
[83]Nielsen CB, Groffman PM, Hamburg SP, et al. Freezing effects on carbon and nitrogen cycling in northern hardwood forest soils. Soil Science Society of America Journal,2001, 65(6):1723-1730.
[84]Lipson DA, Monson RK. Plant-microbe competition for soil amino acids in the alpine tundra:effects of freeze-thaw and dry-rewet events. Oecologia,1998,113(3):406-414.
[85]Hardy JP, Groffman PM, Fitzhugh RD, et al. Snow depth manipulation and its influence on soil frost and water dynamics in a northern hardwood forest. Biogeochemistry,2001, 56(2):151-174.
[86]Wang C K, Yang J Y, Zhang Q Z. Soil respiration in six temperate forests in China. Global Change Biology,2006,12(11):2103-2114.
[87]Wang CK, Yang JY. Rhizospheric and heterotrophic components of soil respiration in six Chinese temperate forests. Global Change Biology,2007,13(1):123-131.
[88]Rey A, Pegoraro E, Tedeschi V, et al. Annual variation in soil respiration and its components in a coppice oak forest in Central Italy. Global Change Biology,2002,8(9): 851-866.
[89]Monson RK, Turnipseed AA, Sparks JP, et al. Carbon sequestration in a high-elevation, subalpine forest. Global Change Biology,2002,8(5):459-478.
[90]Boone RD, Nadelhoffer KJ, Canary JD, et al. Roots exert a strong influence on the temperature sensitivity of soil respiration. Nature,1998,396:570-572.
[91]Epron D, Le Dantec V, Dufrene E, et al. Seasonal dynamics of soil carbon dioxide efflux and simulated rhizosphere respiration in a beech forest. Tree Physiology,2001,21:145-152.
[92]Widen B, Majdi H. Soil CO2 efflux and root respiration at three sites in a mixed pine and spruce forest:seasonal and diurnal variation. Canadian Journal of Forest Research,2001, 31(5):786-796.
[93]Lavigne MB, Boutin R, Foster RJ, et al. Soil respiration responses to temperature are controlled more by roots than by decomposition in balsam fir ecosystems. Canadian Journal of Forest Research,2003,33(9):1744-1753.
[94]Hanson PJ, O'Neill E G, Chambers MLS, et al. Soil respiration and litter decomposition.// Hanson P J, Wullschleger S D. North American Temperate Deciduous Forest Responses to Changing Precipitation Regimes. New York:Springer,2003:163-189.
[2]Marland G, Bode TA, Andres RJ. Global, regional and national CO2 emission, in:Trends: A Compendium of data on global change. Carbon dioxide information analysis center. Oak Rige National Laboratory, US Department of Energy, Oak Rige,Tennessee,2001.
[3]Bouwmann AF, Germon JC. Special issue:soils and climate change:introduction. Biology and Fertility of Soils,1998,27:219.
[4]Singh JS, Gupta SR. Plant decomposition and soil respiration in terrestrial ecosystems. The Botanical Review,1977,43:449-528.
[5]王娓,汪涛,彭书时,方精云.冬季土壤呼吸：不可忽视的地气CO2交换过程.植物生态学报,2007,31(3)：394-402.
[6]Monson RK, Sparks JP, Rosenstiel TN, et al. Climatic influences on net ecosystem CO2 exchange during the transition from wintertime carbon source to springtime carbon sink in a high-elevation, subalpine forest. Oecologia,2005,146:130-147.
[7]Hubbard RM, Ryan MG, Elder K, et al. Seasonal patterns in soil surface CO2 flux under snow cover in 50 and 300 year old subalpine forests. Biogeochemistry,2005,73:93-107.
[8]Grogan P, Michelsen A, Ambus P, et al. Freeze-thaw regime effects on carbon and nitrogen dynamics in sub-arctic heath tundra mesocosms. Soil Biology & Biochemistry, 2004,36(4):641-654.
[9]Herrmann A, Witter E. Sources of C and N contributing to the flush in mineralization upon freeze-thaw cycles in soils. Soil Biology & Biochemistry,2002,34(10):1495-1505.
[10]Schimel JP, Clein JS. Microbial response to freeze-thaw cycles in tundra and taiga soils. Soil Biology &Biochemistry,1996,28(8):1061-1066.
[11]Campbell JL, Mitchell MJ, Groffman PM, et al. Winter in northeastern North America:A critical period for ecological processes. Frontiers in Ecology and the Environment,2005, 3(6):314-322.
[12]Clein JS, Schimel JP. Microbial activity of tundra and taiga soils at subzero temperatures. Soil Biology &Biochemistry,1995,27(9):1231-1234.
[13]Edwards KA, McCulloch J, Kershaw GP, et al. Soil microbial and nutrient dynamics in a wet arctic sedge meadow in late winter and early spring. Soil Biology & Biochemistry, 2006,38(9):2843-2851.
[14]Sommerfeld RA, Massman WJ, Musselman RC. Diffusional flux of CO2 through snow: spatial and temporal variability among alpine-subapline sites. Global Biogeochemical Cycles,1996,10:473-482.
[15]McDowell NG, Marshall JD, Hooker TD. Estimating CO2 flux from snowpacks at three sites in the Rocky Mountains. Tree Physiology,2005,20:745-753.
[16]Suzuki S, Ishizuka S, Kitamura K. Continuous estimation of winter carbon dioxide efflux from the snow surface in a deciduous broadleaf forest. Journal of Geophysical Research. 2006, 111,D17101,doi:10.1029/2005 JD006595.
[17]Zimov SA, Davidov SP, Voropaev YV, et al. Siberian CO2 efflux in winter as CO2 source and cause of seasonality in atmospheric CO2. Climatic Change,1996,33:111-120.
[18]Winston GC, Stephens BB, Trumbore SE. Winter CO2 fluxes in a boreal forest. J. Geophys. Res.1997,102:28795-28804.
[19]Mariko S, Nishimura N, Mo W, et al. Winter CO2 flux from soil and snow surfaces in a cooltemperate deciduous forest, Japan. Ecol. Res.2000,15:363-372.
[20]Mast MA, Wickland KP, Striegl RT, et al. Winter fluxes of CO2 and CH4 from subalpine soils in Rocky Mountain National Park, Colorado. Global Biogeochem. Cycles,1998,12 (4):607-620.
[21]Vogel JG, Valentine DW, Ruess RW. Soil and root respiration in mature Alaskan black spruce forests that vary in soil organic matter decomposition rates. Can. J. Forest Res. 2005,35,161-174.
[22]Brooks PD, McKnight D, Elder K. Carbon limitation of soil respiration under winter snowpacks:potential feedbacks between growing season and winter carbon fluxes. Global Change Biology,2005,11,231-238.
[23]Matzner E, Borken W. Do freeze-thaw events enhance C and N losses from soils of different ecosystems? A review. European Journal of Soil Science,2008,59(2):274-284.
[24]Groffman P M, Hardy J P, Driscoll C T, et al. Snow depth, soil freezing, and fluxes of carbon dioxide, nitrous oxide and methane in a northern hardwood forest. Global Change Biology,2006,12(9):1748-1760.
[25]Muhr J, Borken W, Matzner E. Effects of soil frost on soil respiration and its radiocarbon signature in a Norway spruce forest soil. Global Change Biology,2009,15(4):782-793.
[26]Dorsch P, Palojarvi A, Mommertz S. Overwinter greenhouse gas fluxes in two contrasting agricultural habitats. Nutrient Cycling in Agroecosystems,2004,70:117-133
[27]Prieme A, Christensen S. Natural perturbations, dryingwetting and freezing-thawing cycles, and the emission of nitrous oxide, carbon dioxide and methane from farmed organic soils. Soil Biology & Biochemistry,2001,33:2083-2091.
[28]Monson RK, Lipson DL, Burns SP, et al. Winter forest soil respiration controlled by climate and microbial community composition. Nature,2006,439:711-714.
[29]Elberling B, Brandt KK. Uncoupling of microbial CO2 production and release in frozen soil and its implications for field studies of arctic C cycling. Soil Biology & Biochemistry, 2003,35(2):263-272.
[30]Larsen KS, Jonasson S, Michelsen A.. Repeated freezethaw cycles and their effects on biological processes in two arctic ecosystem types. Applied Soil Ecology,2002,21:187-195.
[31]Dixon RK, Brown S, Houghton RA. Carbon pools and flux of global forest ecosystems. Science,1994,263:185-190.
[32]Sommerfeld RA, Moiser AR, Musselman RC. CO2, CH4, and N2O flux through a Wyoming snowpack and implications for global budgets. Nature,1993,361:140-142.
[33]Brooks PD, Schmidt SK, Williams MW. Winter production of CO2 and N2O from alpine tundra:environmental controls and relationship to inter-system C and N fluxes. Oecologia, 1997,110:403-413.
[34]Brooks PD,Williams MW, Schmidt SK. Microbial activity under alpine snowpacks, Niwot Ridge, Colorado. Biogeochemistry,1996,32:93-113.
[35]Schadt CW, Martin AP, Lipson DL, et al. Seasonal dynamics of previously unknown fungal lineages in tundra soil. Science,2003,301:1359-1361.
[36]Schindlbacher A, Zechmeister-Boltenstern S, Glatzel G, et al. Winter soil respiration from an Austrian mountain forest. Agricultural and Forest Meteorology,2007,146:205-215.
[37]Fang C, Moncrieff JB. The Dependence of Soil CO2 Efflux on Temperature. Soil Biology and Biochemistry,2001,33:155-165.
[38]王庆丰,王传宽,谭立何.移栽自不同纬度的落叶松(Larix gmelinii Rupr.)林的春季土壤呼吸.生态学报,2008,28(5)：1883-1892.
[39]Raich JW, Schlesinger WH. The global carbon dioxide efflux in soil respiration and its relationship to vegetation and climate. Tellus,1992,44:81-90.
[40]Fung IY, Tucker CJ, Prentice KC. Application of advanced very high resolution vegetation index to study atmosphere-biosphere exchange of CO2.Journal of Geophysical Research, 1987,92:299-301
[41]Kicklighter DW. Aspects of spatial and temporal aggregation in estimating regional carbon dioxide fluxes from temperate forest soils. Journal of Geophysical Research,1994,99: 1303-1315.
[42]Jones CD, Cox P, Huntingford C. Uncertainty in climate carbon cycle projections associated with the sensitivity of soil respiration to temperature. Tellus,2003,55B:642-648.
[43]Kirschbaum MUF. Will changes in soil organic carbon act as a positive or negative feedback on global warming? Biogeochemistry,2000,48:21-51.
[44]Davidson EA, Janssens IA, Luo YQ. On the variability of respiration of respiration in terrestrial ecosystems:moving beyond Q10. Global Change Biology,2006,12:154-164.
[45]Mikan C, Schimel J, Doyle A. Temperature controls of microbial respiration above and below freezing in Arctic tundra soils. Soil Biology & Biochemistry,2002,34:1785-1795.
[46]Davidson E A, Belk E, Boone R D. Soil water content and temperature as independent or confounded factors controlling soil respiration in a temperate mixed hardwood forest. Global Change Biology,1998,4(2):217-227.
[47]Fahnestock JT, Jones MH, Brooks PD. Winter and early spring CO2 efflux from tundra communities of northern Alaska. Journal of Geophysical Research Atmosphere,1998,103: 29023-29027.
[48]Koponen HT, Jaakkola T, Keinanen-Toivola MM, et al. Microbial communities, biomass, and activities in soils as affected by freeze thaw cycles. Soil Biology & Biochemistry, 2006,38(7):1861-1871.
[49]Lipson DA, Schmidt SK, Monson RK. Carbon availability and temperature control the post-snowmelt decline in alpine soil microbial biomass. Soil Biology & Biochemistry, 2000,32(4):441-448.
[50]Christensen S, Tiedje JM. Brief and vigorous N2O production by soil at spring thaw. Journal of Soil Science,1990,41:1-4.
[51]Paul EA, Ladd JN. Soil Biochemistry. Marcel Dekker. New York,1981.Vol.5
[52]Clein JS, Schimel JP. Reduction in microbial activity in birch litter due to drying and rewetting events. Soil Biology & Biochemistry,1994,26(3):403-406.
[53]Deluca TH, Keeney DR, Mccarty GW. Effect of freeze-thaw events on mineralization of soil nitrogen.Biology and fertility of soils,1992,14(2):116-120.
[54]Skogland T, Lomeland S, Goksoyr J. Respiratory burst afterfreezing and thawing of soil: experiments with soil bacteria.Soil Biol.Biochem.,1988,20(6):851-856.
[55]Zsolnay A. Dissolved organic matter:artifacts, definitions,and functions. Geoderma, 2003,113:187-209.
[56]Ellert BH, Gregorich EG. Management induced changes in the actively cycling fractions of soil organic matter. In:Mcfee WW, Kelly J M. eds. Carbon Forms and Functions in Forest Soils. Wisconsin, Madison, USA:Soil Science Society of America, Inc.,1995, 119-138.
[57]Wang FL, Bettany JR. Influence of freeze-thaw and flooding on the loss of soluble organic carbon and carbon dioxide from soil. J.Environ.Qual.,1993,22:709-714.
[58]Scott-Denton LE, Rosenstiel TN, Monson RK. Differential controls by climate and substrate over the heterotrophic and rhizospheric components of soil respiration. Global Change Biology,2006,12:205-216.
[59]Winston GC, Stephens BB, Sundquist ET, et al. Seasonal variability in CO2 transport through snow in a boreal forest. In:Tonnessen KA, Williams MW, Tranter M (Eds.), Biogeochemistry of Seasonally Snow-Covered Catchements. IAHS Publication,1995, pp. 61-70.
[60]Kurganova I, de Gerenyu YL, Rozanova L, et al. Annual and seasonal CO2 fluxes from Russian southern taiga soils. Tellus,2003,55B:338-344.
[61]Massman WJ, Sommerfeld RA, Zeller K. CO2 flux through a Wyoming seasonal snowpack:diffusional and pressure pumping effects. In:Hudnell L, Rochelle S eds. Biogeochemistry of Snow-Covered Catchments. International Association of Hydrological Sciences, Wallingford, UK,71-79.
[62]Wang CK. Biomass allometric equations for 10 co-occurring tree species in Chinese temperate forests. Forest Ecology and Management,2006,222:9-16.
[63]Schlesinger WH. Carbon balance in terrestrial detritus. Annual Review of Ecology and Systematics,1977,8:51-81.
[64]Likens GE. A long-term record of ice-cover for Mirror Lake, NH:effects of global warming? Verhandlunden der internationale Vereinigung fu" r theoretische und angewandte Limnologie,2000,27:2765-2769.
[65]Schwartz MD, Reiter BE. Changes in North American spring. International Journal of Climatology,2000,20:929-932.
[66]Dye DG. Variability and trends in the annual snow-cover cycle in Northern Hemisphere land areas,1972-2000. Hydrological Processes,2002,16:305-3077.
[67]Hodgkins GA, Dudley RW, Huntington TG. Changes in the timing of high river flows in New England over the 20th century. Journal of Hydrology,2003,278:244-252.
[68]Wolfe DW, Schwartz MD, Lakso AN, et al. Climate change and shifts in spring phenology of three horticultural woody perennials in northeastern USA. International Journal of Biometeorology,2005,49:303-309.
[69]Williams MW, Brooks PD, Seastedt T. Nitrogen and carbon soil dynamics in response to climate change in a high-elevation ecosystem in the Rocky Mountains, USA. Arctic and Alpine Research,1998,30:26-30.
[70]Murdoch PS, Burns DA, Lawrence GB. Relation of climate change to the acidification of surface waters by nitrogen deposition. Environmental Science and Technology,1998,32: 1642-1647.
[71]Mitchell MJ, Driscoll CT, Kahl JS, et al. Climatic control of nitrate loss from forested watersheds in the northeast United States. Environmental Science and Technology,1996, 30:2609-2612.
[72]Groffman PM, Driscoll CT, Fahey TJ, et al. Colder soils in a warmer world:a snow manipulation study in a northern hardwood forest ecosystem. Biogeochemistry,2001,56: 135-150.
[73]Schimel JP, Bilbrough C, Welker JA. Increased snow depth affects microbial activity and nitrogen mineralization in two Arctic tundra communities. Soil Biology and Biochemistry, 2004,36:217-227.
[74]Valentini R, Matteucci G, Dolman AJ, et al. Respiration as the main determinant of carbon balance in European forests. Nature,2000,404:861-865.
[75]Wang CK, Bond-Lamberty B, Gower ST. Soil surface CO2 flux in a boreal black spruce fire chronosequence. Journal of Geophysical Research-Atmospheres,2002,108(D3):art no.8224.
[76]Xu M, Qi Y. Soil-surface CO2 efflux and its spatial and temporal variations in a young ponderosa pine plantation in northern California. Global Change Biology,2001,7(6):667-677.
[77]Schmidt SK, Wilson KL, Monson RK, et al. Exponential growth of "snow molds" at sub-zero temperatures:an explanation for high beneath-snow respiration rates and Q10 values. Biogeochemistry,2009,95(1):13-21.
[78]Schlesinger WH, Andrews JA. Soil respiration and the global carbon cycle. Biogeochemistry,2000,48(1):7-20.
[79]Raich JW, Potter CS. Global patterns of carbon dioxide emissions from soils. Global Biochemical Cycles,1995,9(1):23-36.
[80]Henry HAL. Soil freeze-thaw cycle experiments:trends, methodological weaknesses and suggested improvements. Soil Biology & Biochemistry,2007,39(5):977-986.
[81]Raich JW, Tufekcioglu A. Vegetation and soil respiration:Correlations and controls. Biogeochemistry,2000,48(1):71-90.
[82]Goldberg SD, Muhr J, Borken W, Gebauer G. Fluxes of climate-relevant trace gases between a Norway spruce forest soil and atmosphere during repeated freeze-thaw cycles in mesocosms. Journal of Plant Nutrition and Soil Science,2008,171(5):729-739.
[83]Nielsen CB, Groffman PM, Hamburg SP, et al. Freezing effects on carbon and nitrogen cycling in northern hardwood forest soils. Soil Science Society of America Journal,2001, 65(6):1723-1730.
[84]Lipson DA, Monson RK. Plant-microbe competition for soil amino acids in the alpine tundra:effects of freeze-thaw and dry-rewet events. Oecologia,1998,113(3):406-414.
[85]Hardy JP, Groffman PM, Fitzhugh RD, et al. Snow depth manipulation and its influence on soil frost and water dynamics in a northern hardwood forest. Biogeochemistry,2001, 56(2):151-174.
[86]Wang C K, Yang J Y, Zhang Q Z. Soil respiration in six temperate forests in China. Global Change Biology,2006,12(11):2103-2114.
[87]Wang CK, Yang JY. Rhizospheric and heterotrophic components of soil respiration in six Chinese temperate forests. Global Change Biology,2007,13(1):123-131.
[88]Rey A, Pegoraro E, Tedeschi V, et al. Annual variation in soil respiration and its components in a coppice oak forest in Central Italy. Global Change Biology,2002,8(9): 851-866.
[89]Monson RK, Turnipseed AA, Sparks JP, et al. Carbon sequestration in a high-elevation, subalpine forest. Global Change Biology,2002,8(5):459-478.
[90]Boone RD, Nadelhoffer KJ, Canary JD, et al. Roots exert a strong influence on the temperature sensitivity of soil respiration. Nature,1998,396:570-572.
[91]Epron D, Le Dantec V, Dufrene E, et al. Seasonal dynamics of soil carbon dioxide efflux and simulated rhizosphere respiration in a beech forest. Tree Physiology,2001,21:145-152.
[92]Widen B, Majdi H. Soil CO2 efflux and root respiration at three sites in a mixed pine and spruce forest:seasonal and diurnal variation. Canadian Journal of Forest Research,2001, 31(5):786-796.
[93]Lavigne MB, Boutin R, Foster RJ, et al. Soil respiration responses to temperature are controlled more by roots than by decomposition in balsam fir ecosystems. Canadian Journal of Forest Research,2003,33(9):1744-1753.
[94]Hanson PJ, O'Neill E G, Chambers MLS, et al. Soil respiration and litter decomposition.// Hanson P J, Wullschleger S D. North American Temperate Deciduous Forest Responses to Changing Precipitation Regimes. New York:Springer,2003:163-189.