Winter soil CO2 efflux and its contribution to annual soil respiration in different ecosystems of a forest-steppe ecotone, north China
Winter soil CO2 efflux and its contribution to annual soil respiration in different ecosystems of a forest-steppe ecotone, north China
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DOI：
10.1016/j.soilbio.2009.11.028
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发表时间：
2010-03
影响因子：
9.7
通讯作者：
Wei Wang;S. Peng;Tao Wang;Jingyun Fang
中科院分区：
文献类型：
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作者：
Wei Wang;S. Peng;Tao Wang;Jingyun Fang
大多数土壤呼吸测量是在生长季节进行的。据报道，在苔原和北方森林生态系统中，冬季土壤累积二氧化碳通量是其年度碳预算的重要组成部分。然而，关于中纬度生态系统冬季土壤二氧化碳流出的信息知之甚少。因此，比较每年与生长季节的土壤呼吸测量结果将提高生态系统碳预算的准确性以及土壤二氧化碳流出对气候变化的响应。在本研究中，我们测量了中国北方森林草原交错带的七个生态系统（三个森林：樟子松人工林、华北落叶松人工林和白桦林；两种灌木：蔷薇和海棠；以及两个草甸草原）的冬季土壤二氧化碳流出及其对年度土壤呼吸的贡献。冬季和生长季土壤CO2排放量总体平均分别为0.15–0.26 μmol m−2s−1和2.65–4.61 μmol m−2s−1，不同生态系统的生长季差异显着。年Q10（温度每升高10°C，土壤呼吸速率增加）一般高于生长季Q10。土壤含水量解释了生长季Q10变化的84%，土壤温度范围解释了年Q10变化的88%。 30 厘米深度的土壤有机碳密度是 SR10（参考温度为 10 °C 时的基础土壤呼吸）的良好替代指标。使用观察到的土壤呼吸和土壤温度之间的生态系统特定响应方程，年土壤 CO2 流出量范围为 394.76 g C m−2 至 973.18 g C m−2。通过在一年中每一天的采样日期之间插入测得的土壤呼吸，然后计算总和以获得年度值，估计范围为 424.90 g C m−2 至 784.73 g C m−2。使用插值法和建模方法，冬季土壤CO2流出对年土壤呼吸的贡献分别为3.48-7.30%和4.92-7.83%。我们的研究结果表明，在中纬度生态系统中，土壤二氧化碳流出持续整个冬季，冬季土壤呼吸是年度二氧化碳流出的重要组成部分。
Most soil respiration measurements are conducted during the growing season. In tundra and boreal forest ecosystems, cumulative winter soil CO2fluxes are reported to be a significant component of their annual carbon budgets. However, little information on winter soil CO2efflux is known from mid-latitude ecosystems. Therefore, comparing measurements of soil respiration taken annually versus during the growing season will improve the accuracy of ecosystem carbon budgets and the response of soil CO2efflux to climate changes. In this study we measured winter soil CO2efflux and its contribution to annual soil respiration for seven ecosystems (three forests: Pinus sylvestris var. mongolica plantation, Larix principis-rupprechtii plantation and Betula platyphylla forest; two shrubs: Rosa bella and Malus baccata; and two meadow grasslands) in a forest-steppe ecotone, north China. Overall mean winter and growing season soil CO2effluxes were 0.15–0.26 μmol m−2s−1and 2.65–4.61 μmol m−2s−1, respectively, with significant differences in the growing season among the different ecosystems. Annual Q10(increased soil respiration rate per 10 °C increase in temperature) was generally higher than the growing season Q10. Soil water content accounted for 84% of the variations in growing season Q10and soil temperature range explained 88% of the variation in annual Q10. Soil organic carbon density to 30 cm depth was a good surrogate for SR10(basal soil respiration at a reference temperature of 10 °C). Annual soil CO2efflux ranged from 394.76 g C m−2to 973.18 g C m−2using observed ecosystem-specific response equations between soil respiration and soil temperature. Estimates ranged from 424.90 g C m−2to 784.73 g C m−2by interpolating measured soil respiration between sampling dates for every day of the year and then computing the sum to obtain the annual value. The contributions of winter soil CO2efflux to annual soil respiration were 3.48–7.30% and 4.92–7.83% using interpolated and modeled methods, respectively. Our results indicate that in mid-latitude ecosystems, soil CO2efflux continues throughout the winter and winter soil respiration is an important component of annual CO2efflux.