Seasonal and annual variations in soil respiration in a cool-temperate deciduous broad-leaved forest in Japan
Seasonal and annual variations in soil respiration in a cool-temperate deciduous broad-leaved forest in Japan
复制标题
DOI：
10.1016/j.agrformet.2005.08.015
复制
发表时间：
2005-11-30
影响因子：
6.2
通讯作者：
Koizumi, H
中科院分区：
文献类型：
--
作者：
Mo, W;Lee, MS;Koizumi, H
我们调查了在日本中部的冷温带橡树-桦树林土壤呼吸的季节性和年度变化，特别是，揭示了决定呼吸的温度依赖性的季节性变化的因素的基础上，土壤CO2排放数据为1999-2002年。春末土壤碳排放量适中（5月为1.8-2.9 g Cm（-2）d（-1）），夏季急剧增加，达到峰值（8月为4.6-6.0 g Cm（-2）d（-1）），秋季下降（11月为1.5-2.5 g Cm（-2）d（-1））。冬季雪面碳排放量较低（0.29-0.71 g Cm（-2）d（-1））。土壤温度对土壤呼吸的季节和年际变化起主要控制作用。此外，土壤水分含量降低降低土壤呼吸在夏季干旱发生时。在季节尺度上驱动的温度函数显示出较大的季节变化Q（10）和R-0（模拟土壤温度为0 ℃时的土壤呼吸），例如春季较高的Q（10）和较低的R-0，秋季较低的Q（10）和较高的R-0。Q（10）和R-0的这些大的季节性变化可能反映了温度敏感性和由根物候、微生物生物量和其他因素引起的生理活动的季节性变化的混杂效应。这些结果表明，如果要模拟特定季节的土壤呼吸，必须使用从目标时期导出的季节Q（10）函数，特别是在具有明显季节变化的森林生态系统中。相反，根据4年内-1 cm处每日土壤温度的所有测量值得出的年度Q（10）函数（Q（10）= 3，8）足以估计年度土壤呼吸总量，因为它可以整合影响土壤碳流出的所有过程，尽管它可能低估或高估季节尺度上的每日土壤碳流出。基于这一单一的年Q（10）函数，在1999-2002年，不经地形校正的年平均土壤呼吸为853.5 +/- 42.4 g Cm（-2），经地形校正的年平均土壤呼吸为725.5 +/- 36.0 g Cm（-2）。年土壤呼吸（1999-2002年）的变异系数（CV）小于10%，表明1999-2002年该森林年土壤呼吸的年际变化较小，因为4年的年平均温度相似。雪面碳排放量占全年土壤呼吸量的10%，为84.3 +/- 7.0 g Cm（-2），表明了对寒冷多雪地区森林生态系统冬季CO2排放量进行定量研究的重要性。(c)2005 Elsevier B. V.保留所有权利。
We investigated the seasonal and annual variations in soil respiration in a cool-temperate oak-birch forest in central Japan and, in particular, to reveal factors determining seasonal variations in the temperature dependence of respiration based on soil CO2 efflux data for 1999-2002. The daily soil carbon efflux was moderate in late spring (1.8-2.9 g C m(-2) day-1 in May), increased sharply to a peak in summer (4.6-6.0 g C m(-2) day(-1) in August), and decreased in autumn (1.5-2.5 g C m(-2) day(-1) in November). In winter, the carbon efflux from the snow Surface was low (0.29-0.71 g C m(-2) day(-1)). Soil temperature exerted principle control on the seasonal and annual variation of soil respiration. Furthermore, reduced soil water content decreased soil respiration in summer when droughts occurred. The temperature function driven on a seasonal scale showed large variations in seasonal Q(10) and R-0 (simulated soil respiration at a soil temperature of 0 degrees C), e.g. a higher Q(10) and lower R-0 in spring and a lower Q(10) and higher R-0 in autumn. These large variations in seasonal Q(10) and R-0 might reflect confounding effects of temperature sensitivity and seasonal changes in physiological activities induced by root phenology, microbial biomass, and other factors. These results suggest that if the objective is to simulate soil respiration in a particular season, a seasonal Q(10) function derived from the target period must be used, especially in a forest ecosystem possessing distinct seasonal changes. Conversely, the annual Q(10) function derived front all measurements of daily soil temperature at -1 cm across the 4 years (Q(10) = 3,8) was adequate for estimating total annual soil respiration because it may integate all processes that influence soil carbon efflux, despite the fact it may under- or overestimate daily soil carbon efflux on a seasonal scale. Based on this single annual Q(10) function, the annual mean soil respiration in 1999-2002 was estimated to be 853.5 +/- 42.4 g C m(-2) without topography correction, and 725.5 +/- 36.0 g C m(-2) with topography correction for a 1 ha experimental area. The estimated annual soil respiration (1999-2002) gave coefficient of variation (CV) value of less than 10%, suggesting a small inter-annual variability in annual soil respiration during 1999-2002 in this forest, since the annual mean temperature was similar in the 4 years of the survey. Carbon efflux from the Snow Surface accounted for 10% of the annual soil respiration, with a value of 84.3 +/- 7.0 g C m(-2), indicating the importance of quantifying winter CO2 efflux within a forest ecosystem in a cold and snowy region. (c) 2005 Elsevier B.V. All rights reserved.