影响土壤呼吸的因子有很多，在不同时间空间的不同生态系统其影响因子各不相同。综述了土壤呼吸主要影响因子的研究进展，主要从土壤温度、土壤湿度、降水、土壤C/N等非生物因子，植被类型、生物量、叶面积指数、植被凋落物等生物因子以及人类活动等方面阐述对土壤呼吸产生的影响。在此基础上对土壤呼吸的Q₁₀值、关键影响因子及各种生态环境因子的综合影响进行了讨论。从众多研究中发现土壤温度、湿度是影响土壤呼吸的主要因子，建立土壤温度及湿度影响下的土壤呼吸模型更有助于对土壤呼吸进行定量的描述。但是在土壤温度及湿度过高或过低的情况下会出现较大的误差，为了尽量减少土壤呼吸的误差，给出了如下建议：①加强土壤呼吸和生态系统自动碳通量的结合研究；②加强对不同生物和非生物生态环境因子的同步测定，特别重视生物因子对非生物因子的调节和影响；③加强典型物候期和不同季节典型天气土壤呼吸的测定；④加强模拟试验研究和模式研究。总之，土壤呼吸是一个比较复杂的过程，虽然有规律可循，但是，很多时候由于因子间交互作用而表现偏离，对其准确估算需要找出关键因子，并综合分析其它因子的影响。

Soil respiration is influenced by many factors, which are different in a variety of spatiotemporal ecosystems. The objective of this paper is to review the main factors including abiotic factors such as the soil temperature, soil moisture, rainfall, soil C/N，biotic factors such as vegetation types, biomass, leaf area index, litter, and human activities as well. Based on the summarization, the Q₁₀ of soil respiration, key controlling factors and interaction among different factors were discussed. Soil temperature, soil moisture are the key factors controlling soil respiration. So it is helpful to estimate the amount of soil respiration on the basis of modeling by these factors. However, the prediction has a limitation of underestimation and overestimation at low and high temperature or moisture conditions respectively. In order to acquire accurate estimation of soil respiration, main suggestions for further study are to: combine measurement of soil respiration by chamber with carbon flux of ecosystem by eddy covariance, measure synchronously the biotic and abiotic factors, especially pay more attention to the role of modification of biotic factors on the performance of abiotic controllers, make more measurement in typical plant phenology phase and different weather conditions, and strengthen experimental manipulation and modeling. In conclusion, soil respiration is a complex biochemical process, which is controlled by certain models although regulated by interactions among multi-factors. In order to get accurate modeling and prediction, key factors need to be sought and estimate synthetic influence of interactive factors.

In a 26-year soil warming experiment in a mid-latitude hardwood forest, we documented changes in soil carbon cycling to investigate the potential consequences for the climate system. We found that soil warming results in a four-phase pattern of soil organic matter decay and carbon dioxide fluxes to the atmosphere, with phases of substantial soil carbon loss alternating with phases of no detectable loss. Several factors combine to affect the timing, magnitude, and thermal acclimation of soil carbon loss. These include depletion of microbially accessible carbon pools, reductions in microbial biomass, a shift in microbial carbon use efficiency, and changes in microbial community composition. Our results support projections of a long-term, self-reinforcing carbon feedback from mid-latitude forests to the climate system as the world warms.Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Climate warming may be exacerbated if rising temperatures stimulate losses of soil carbon to the atmosphere. The direction and magnitude of this carbon-climate feedback are uncertain, largely due to lack of knowledge of the thermal adaptation of the physiology and composition of soil microbial communities. Here, we applied the macromolecular rate theory (MMRT) to describe the temperature response of the microbial decomposition of soil organic matter (SOM) in a natural long-term warming experiment in a geothermally active area in New Zealand. Our objective was to test whether microbial communities adapt to long-term warming with a shift in their composition and their temperature response that are consistent with evolutionary theory of trade-offs between enzyme structure and function. We characterized the microbial community composition (using metabarcoding) and the temperature response of microbial decomposition of SOM (using MMRT) of soils sampled along transects of increasing distance from a geothermally active zone comprising two biomes (a shrubland and a grassland) and sampled at two depths (0-50 and 50-100 mm), such that ambient soil temperature and soil carbon concentration varied widely and independently. We found that the different environments were hosting microbial communities with distinct compositions, with thermophile and thermotolerant genera increasing in relative abundance with increasing ambient temperature. However, the ambient temperature had no detectable influence on the MMRT parameters or the relative temperature sensitivity of decomposition (Q ). MMRT parameters were, however, strongly correlated with soil carbon concentration and carbon:nitrogen ratio. Our findings suggest that, while long-term warming selects for warm-adapted taxa, substrate quality and quantity exert a stronger influence than temperature in selecting for distinct thermal traits. The results have major implications for our understanding of the role of soil microbial processes in the long-term effects of climate warming on soil carbon dynamics and will help increase confidence in carbon-climate feedback projections.© 2021 The Authors. Global Change Biology published by John Wiley & Sons Ltd.

A common effect size metric used to quantify the outcome of experiments for ecological meta-analysis is the response ratio (RR): the log proportional change in the means of a treatment and control group. Estimates of the variance of RR are also important for meta-analysis because they serve as weights when effect sizes are averaged and compared. The variance of an effect size is typically a function of sampling error; however, it can also be influenced by study design. Here, I derive new variances and covariances for RR for several often-encountered experimental designs: when the treatment and control means are correlated; when multiple treatments have a common control; when means are based on repeated measures; and when the study has a correlated factorial design, or is multivariate. These developments are useful for improving the quality of data extracted from studies for meta-analysis and help address some of the common challenges meta-analysts face when quantifying a diversity of experimental designs with the response ratio.

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利用红外辐射增温装置模拟短期持续增温和降水增加交互作用对内蒙古荒漠草原土壤呼吸作用的影响, 结果表明: 土壤含水量对月土壤呼吸的影响显著大于土壤温度增加的影响, 生长旺季的月土壤呼吸显著大于生长末季; 土壤温度和水分增加都显著影响日土壤呼吸, 但二者的交互作用对土壤呼吸无显著影响。荒漠草原7?8月平均土壤呼吸速率为1.35 μmol CO₂·m^–2·s^–1, 7月份为2.08 μmol CO₂·m^–2·s^–1, 8月份为0.63 μmol CO₂·m^–2·s^–1。土壤呼吸与地下各层根系生物量呈幂函数关系, 0?10 cm土层的根系生物量对土壤呼吸的解释率(79.2%)明显高于10?20 cm土层的解释率(31.6%)。0–10 cm土层的根系生物量是根系生物量的主体, 根系生物量对土壤呼吸的影响具有层次性。在未来全球变暖和降水格局变化的情景下, 荒漠草原土壤水分含量是影响生物量的主导环境因子, 而根系生物量的差异是造成土壤呼吸异质性的主要生物因素, 土壤含水量可通过影响根系生物量控制土壤呼吸的异质性。

<p><em>Aims </em>Our objective was to examine the effects of global warming inducing environmental and biological changes on soil respiration of desert steppe.</br><em>Methods</em> We used infrared heaters to carry out the interactive simulation of warming and increasing precipitation in a desert steppe of Inner Mongolia from June to September 2011. Our experimental design was set up with two temperature levels (control and warming) and three precipitation treatments (control, 15% and 30% increase of the average precipitation during 1987&ndash;2007), using a complete randomized block arrangement. Soil respiration rate was measured by a LI-8100 carbon flux system in these six different treatments. We analyzed the relationships between soil respiration and environmental factors, aboveground biomass, and belowground biomass at different soil layers (0&ndash;10, 10&ndash;20 and 0&ndash;20 cm).</br><em>Important findings</em> Soil respiration in the desert steppe reached its peak value in the middle of the growing season. The average soil respiration rate of the desert steppe from July to August was 1.35 &mu;mol CO₂&middot;m^&ndash;2&middot;s^&ndash;1. The soil respiration rate was 2.08 and 0.63 &mu;mol CO₂&middot;m^&ndash;2&middot;s^&ndash;1 in July and August, respectively. Increasing soil moisture and temperature significantly influenced daily soil respiration, but their interaction had no significant effect on soil respiration. Soil moisture had greater impact on monthly soil respiration than soil temperature. Soil respiration rate showed a power function relationship with belowground biomass at different soil depths. The belowground biomass at 0&ndash;10 cm soil was the major part of the belowground biomass and could explain more variation of soil respiration rate (79.2%) than that at 10&ndash;20 cm (31.6%). Under the future climatic changes scenarios, soil moisture was a principal environmental factor affecting plant biomass, while belowground biomass was a major biological factor controlling soil respiration in the desert steppe. Soil moisture might control the heterogeneity of soil&nbsp;respiration by influencing the distribution of belowground biomass at different soil depths.</p>

采用开顶式增温小室（OTC）和外源氮素添加的方式，研究了气温升高、氮沉降增加及其交互作用对青藏高原腹地生长季沼泽草甸生态系统呼吸的短期影响。结果表明：增温、施氮及其交互作用通过促进植物生物量积累、增加微生物数量与活性以及改变土壤养分状况，对沼泽草甸生态系统呼吸速率均产生了显著的促进作用；生态系统呼吸与单一环境因子间符合指数或二次多项式关系，但两种关系的显著性随着样地处理方式趋向复杂而逐渐降低；由于沼泽草甸充足的水分条件，气温和土壤温度共同决定了不同处理内80%的生态系统呼吸变异；增温使地上与地下生物量显著增加，但地下生物量的分配比例上升；施氮使地上生物量明显增加，但对地下生物量的影响不显著；增温同时施氮使地上及地下生物量均显著上升，但生物量的分配格局变化并不显著。

To investigate the interactive effects of global warming and increased nitrogen deposition on ecosystem respiration, a short-term experiment was carried out during growth season in an alpine swamp meadow of Qinghai-Tibetan Plateau, using open top champers (OTC) and nitrogen addition to simulate warming and nitrogen deposition, respectively. Warming, nitrogen addition, and their interaction significantly increased ecosystem respiration rate by affecting plant biomass, soil microbial quantity and activity, and soil nutrient status. The correlations between ecosystem respiration and each of the environmental factors were exponential or quadric multinomial, with the significance levels of such regressions declining with the increases of complexity of treatments. As soil water availability is sufficient in swamp meadow, air temperature and soil temperature at the depth of 5 cm could explain 80% of the variations of ecosystem respiration. Warming significantly increased above and below-ground biomass, and enhanced the proportions of below-ground biomass. Nitrogen addition significantly increased above-ground biomass and had no effect on below-ground biomass. Under warming condition, nitrogen addition significantly increased above and below-ground biomass, but with no impacts on biomass allocation.

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To investigate the effects of elevated temperature on the soil organic carbon content, soil respiration rate, and soil enzyme activities in subalpine Picea asperata plantations in western Sichuan Province of China, a simulation study was conducted in situ with open-top chambers from November 2005 to July 2007. The results showed that under elevated temperature, the mean air temperature and soil temperature were 0.42 degrees C and 0.25 degrees C higher than the control, respectively. In the first and the second year, the increased temperature had somewhat decreasing effects on the soil organic carbon and the C/N ratio at the soil depths of 0-10 cm and 10-20 cm. In the first year the soil organic carbon and the C/N ratio in 0-10 cm soil layer decreased by 8.69%, and 8.52%, respectively; but in the second year, the decrements were lesser. Soil respiration rate was significantly enhanced in the first year of warming, but had no significant difference with the control in the second year. In the first year of warming, the activities of soil invertase, polyphenol oxidase, catalase, protease, and urease increased, and the invertase and polyphenol oxidase activities in 0-10 cm soil layer were significantly higher than the control. In the second year of warming, the activities of invertase, protease and urease still had an increase, but those of catalase and polyphenol oxidase had a downtrend, compared with the control.

土壤呼吸作用作为陆地生态系统碳循环的重要组成部分,是当前碳循环研究中的热点问题.对于土壤呼吸作用主要组成部分土壤微生物呼吸作用和根系呼吸作用影响因子的研究,有助于准确地评估全球碳收支.本文从气候、土壤、植被及地表覆被物、大气CO₂浓度、人为干扰等方面综述了土壤微生物呼吸作用和根系呼吸作用的主导影响因子,指出这些影响因子不仅直接或间接地影响土壤微生物呼吸作用和根系呼吸作用,而且它们之间相互作用、相互影响,且各影响因子的地位和作用会随时空尺度变化发生相应改变.在此基础上,论文提出了未来土壤呼吸作用的研究重点.

Soil respiration is an important part of the carbon cycle in terrestrial ecosystems, and its contribution to the global carbon budget has been the focus of wide concern.Researches on the affecting factors of soil microorganism and root respiration,the main components of soil respiration, contribute to the understanding of the role of soil respiration on global carbon cycle,and to the accurate evaluation of global carbon budget.This paper reviewed the direct and indirect affecting factors of soil microorganism and root respiration,including climate factors,soil properties,vegetation and litterfall,air CO2 concentration,and human activities.These affecting factors were interactive,and their contributions to soil microorganism and root respiration varied in temporal and spatial scales.The study on natural and anthropogenic factors of soil microorganism and root respiration was emphasized,and some related research tasks in the future were also proposed.

大气温度的升高及凋落物的分解通过影响土壤微生物的活动,从而影响土壤呼吸。采用开顶箱式增温（Open Top Chamber,OTC）,结合静态箱-气相色谱法,于2020年生长季（5&#x02014;10月）野外原位观测内蒙古大青山油松（Pinus tabuliformis Carr.）人工林土壤呼吸。试验设置对照（CK）、模拟增温（W）、去除凋落物（NL）、模拟增温+凋落物去除（WNL）4个处理4次重复,同时测定了大气温湿度、土壤温湿度及土壤理化性质。结果表明,（1）增温处理1年后,大气温度、土壤5、10和20 cm处的温度分别较对照增加了1.21、0.50、0.43和0.57 ℃;土壤5、10和20 cm的含水量分别较对照降低了5.4%、7.1%和6.4%。（2）大青山油松人工林土壤CO₂通量变化范围为224.19&#x02014;601.15 mg&#x02219;m^-2&#x02219;h^-1;CH₄通量范围为-28.45&#x02014; -90.2 &#x003bc;g&#x02219;m^-2&#x02219;h^-1;N₂O通量范围为3.94&#x02014;10.78 &#x003bc;g&#x02219;m^-2&#x02219;h^-1。整个生长季4种处理下土壤均表现为CO_2、N₂O的排放源、CH₄的吸收汇。（3）对照和模拟增温处理下土壤CO₂通量与大气温度和土壤温度（0&#x02014;5、5&#x02014;10、10&#x02014;20 cm）呈极显著正相关（P<0.01）,与土壤TN（0&#x02014;10 cm）呈极显著负相关（P<0.01）,与土壤TN（10&#x02014;20 cm）呈显著负相关（P<0.05）;土壤CH₄通量仅在W处理下与大气湿度呈显著负相关（P<0.05）;土壤N₂O通量在W处理下与土壤TN（0&#x02014;10、10&#x02014;20 cm）呈显著负相关（P<0.05）。由此可见,气候变化及地表凋落物层是影响森林土壤呼吸的重要因素;基于100 a时间尺度计算温室气体全球综合增温潜势,模拟增温和凋落物处理下土壤温室气体的排放对气候变暖具有正反馈作用。

多年冻土温室气体排放对全球气候变化有重要影响。采用静态暗箱—气相色谱法,于2016—2017年生长季（5—9月）,对大兴安岭多年冻土区兴安落叶松林、樟子松林和白桦林土壤二氧化碳（CO₂）、甲烷（CH₄）和氧化亚氮（N₂O）通量进行野外原位观测,对比分析温室气体通量的动态变化特征及其关键影响因子。结果表明：3种林型土壤CO₂通量范围为65.88~883.59 mg·m^-2·h^-1;CH₄通量范围为-93.29~-2.82 μg·m^-2·h^-1;N₂O通量范围为-5.31~45.22 μg·m^-2·h^-1。整个生长季兴安落叶松林、樟子松林和白桦林土壤均表现为CO₂、N₂O的排放源、CH₄的吸收汇,土壤CO₂和CH₄通量在不同林型和年际间差异显著。3种林型土壤CO₂通量与5 cm、10 cm和15 cm土壤温度呈极显著正相关（P < 0.01）;CH₄通量受土壤含水量和10 cm、15 cm土壤温度的影响较大（P < 0.05）;兴安落叶松林和樟子松林土壤N₂O通量与气温呈显著正相关（P < 0.05）,而白桦林土壤N₂O则与15 cm土壤温度呈显著负相关（P < 0.05）。基于100 a时间尺度计算温室气体全球综合增温潜势,3种林型土壤温室气体的排放对气候变暖具有正反馈作用。

Greenhouse gases from permafrost have a significant impact on global climate change. The in situ static dark chamber and gas chromatography techniques were used to monitor the fluxes of carbon dioxide (CO₂), methane (CH₄), and nitrous dioxide (N₂O) from the typical forest soils of Larix gmelini, Pinus sylvestris, and Betula platyphylla in the permafrost regions of the Greater Hinggan Mountains. The experiment was conducted during the growing season (May to September) of 2016 and 2017. The dynamic characteristics of greenhouse gas fluxes and the controlling factors were comparatively analyzed. The results showed that soil CO₂, CH₄, and N₂O fluxes of the three forest types were 65.88-883.59 mg·m^-2·h^-1, -93.29--2.82 μg·m^-2·h^-1, and -5.31-45.22 μg·m^-2·h^-1, respectively. The soils from the three typical forests were all sources for CO₂ and N₂O, and sink for CH₄ during the entire observation period. Soil CO₂ and CH₄ fluxes changed significantly among different forest types and between the two observation periods. The soil CO₂ fluxes of the three forest types were mainly controlled by soil temperature and were found to have a significantly positive correlation with the soil temperature at 5, 10, and 15 cm (P < 0.01). The soil CH₄ fluxes were affected by soil water content and soil temperature. The correlations were significant in the soils at 10 and 15 cm (P < 0.05). Moreover, the air temperature controlled and regulated soil N₂O fluxes. The soil N₂O fluxes in the Betula platyphylla forest showed a significantly negative correlation with the soil temperature at 15 cm (P < 0.05). The emission rate of soil CO₂ and N₂O accelerated with increasing temperature, while the absorption rate of CH₄ decreased, enhancing the atmospheric greenhouse effect. The global warming potential of greenhouse gases was calculated based on the 100-year time scale, where the soil greenhouse gases of the three forest types exhibited a positive feedback on climate warming.

东北地区森林生态系统因其面积大，碳贮量高而在本地区和我国碳平衡中占有重要的地位。土壤表面CO₂通量(RS)作为陆地生态系统向大气圈释放的主要CO₂源，其时空变化直接影响到区域碳循环。该研究采用红外气体分析法比较测定我国东北东部次生林区6个典型的森林生态系统的RS及其相关的土壤水热因子，并深入分析土壤水热因子对RS的影响。研究结果表明：影响RS的主要环境因子是土壤温度、土壤含水量及其交互作用，但其影响程度因生态系统类型和土壤深度而异。包括这些环境因子的综合RS模型解释了 67.5%～90.6%的RS变异。在整个生长季中，不同生态系统类型的土壤温度差异不显著 ，而土壤湿度的差异显著(&alpha;= 0.05)。蒙古栎(Quercus mongolica)林、红松(Pinus koraiensis)林、 落叶松(Larix gmelinii)林、硬阔叶林、杂木林和杨桦(Populus davidiana_Betula platyphylla)林的RS变化范围依次为：1.89～5.23 &micro;mol CO₂&bull;m^－2&bull;s^－1，1.09～4.66&micro;mol CO₂&bull;m^－2&bull;s^－1，0.95～3.52&micro;mol CO₂&bull;m^－2&bull;s^－1，1. 13～5.97&micro;mol CO₂&bull;m^－2&bull;s^－1，1.05～6.58&micro;mol CO₂&bull;m^－2&bull;s^－1和1.11～5.76&micro;mol CO₂&bull;m^－2&bull;s^－1。RS的季节动态主要受土壤水热条件的驱动而呈现单峰曲线，其变化趋势大致与土壤温度的变化相吻合。Q₁₀从小到大依次为：蒙古栎林2.32，落叶松林2.57，红松 林2.76，硬阔叶林2.94，杨桦林3.54和杂木林3.55。Q₁₀随土壤湿度的升高而增大；但超过 一定的阈值后，土壤湿度对Q₁₀起抑制作用。该研究结果强调对该地区生态系统 土壤表面CO₂通量的估测应同时考虑土壤水热条件的综合效应。

<p>Forest ecosystems in northeastern China play an important role in both local and national carbon budgets because of their large area extent and huge amount of carbon storage. The spatial and temporal changes in soil surface CO2 flux (RS), the major CO2 source to the atmosphere from terrestrial ecosystem s, directly influence the local and regional carbon budgets. However, few data on RS were available for this region. In this study, we used an infrared gas exchange analyzer (LI_COR 6400) to measure the RS and related biophysical factors, and examined soil temperature and moisture effects on soil respiration for six secondary temperate forest ecosystem types: Mongolian oak (dominated by Quercus mongolica), poplar_birch (dominated by Populus davidiana and Betula platyphylla), mixed_wood (no dominant tree species), hard_wood forests (dominated by Fraxinus mandshurica, Juglans mandshurica and Phellodendron amurense), Korean pine ( Pinus koraiensis) and Dahurian larch (Larix gmelinii) plantations. Our specific objectives were to: 1) compare the soil temperature, soil moisture, RS, and Q10 (temperature coefficient) of the six forest types; 2) quantify the seasonality of RS and related environmental factors; and 3) determine the environmental factors affecting the RS, and construct models of RS against the related environmental factors.  Soil temperature, soil moisture and their interactions significantly (p < 0. 01) influenced the RS, but their effects depended on forest type and soil depth. These factors could explain 67.5%－90.6% of the variations in the RS data. During the growing season, the soil temperature at 10 cm depth in the different forest types did not differ significantly but soil moisture did. The RS for the oak, pine, larch, hardwood, mixed_wood, and poplar_birch stands varied from 1.89－5.2 3, 1.09－4.66, 0.95－3.52, 1.13－5.97, 1.05－6.58, and 1.11－5.76 &micro;mol CO2&bull;m－2&bull;s－1, respectively; the Q10values for those stands were 2.32, 2.76, 2.57, 2.94, 3.55 and 3.54, correspondingly. The seasonality of RS was driven mainly by soil temperature and moisture, and was roughly consistent with that of soil temperature. The broad_leaved forests had a higher soil respiration rate than those of coniferous forests probably because of a more suitable soil thermal and moisture regimes and other biological factors.  The temperature sensitivity coefficient of soil respiration (Q10) showed a convex_type curve along a soil moisture gradient. The Q10tended to increase when soil moisture increased from 30.19 to 40.7, and then declined probably because the extremely high soil moisture content in the hardwood forest may impede activities of soil microbes and plant roots, and thus decrease decomposition rates and soil CO2 emission. Our study strongly recommended that estimation of soil surface CO2 flux from forest ecosystems should consider the comprehensive effects of both soil temperature and moisture on soil respiration so as to reduce uncertainties of ecosystem carbon budget studies in this region.</p>

明确荒漠绿洲过渡区土壤呼吸及其温湿度敏感性特征，对了解干旱、半干旱地区土壤碳循环有重要意义。本研究采用LI-8100土壤呼吸观测系统对河西走廊典型荒漠绿洲过渡区荒漠梭梭林地、绿洲农田、人工杨树林地3种不同土地利用类型的土壤呼吸进行1年的观测。结果表明，3种土地利用类型全年平均土壤呼吸为人工杨树林地（2.20 &mu;mol CO₂&middot;m^-2&middot;s^-1）>绿洲农田（1.61 &mu;mol CO₂&middot;m^-2&middot;s^-1）>荒漠梭梭林地（0.40 &mu;mol CO₂&middot;m^-2&middot;s^-1），造成不同土地利用类型土壤呼吸显著差异的原因主要与土壤有机碳含量有关。Lloyd-Taylor指数模型能够较好拟合土壤呼吸季节性变化与温度的关系。3种不同土地利用类型的土壤呼吸均在低温时（非生长季）较高温时（生长季）对温度变化更敏感。在全年尺度上，不同土地利用类型的土壤呼吸与土壤温度呈极显著正相关（P<0.01）；荒漠梭梭林地、绿洲农田的土壤呼吸与土壤水分呈极显著正相关（P<0.01），人工杨树林地土壤水分低于6%时和高于6%时，土壤呼吸与土壤水分分别呈极显著正相关（P<0.01）和显著负相关（P<0.05）。本研究结果为干旱区绿洲化过程土壤碳循环的研究提供了基础数据。

Clarifying the sensitivity of soil respiration to the variation of temperature and moisture in the desert-oasis region would be a great contribution to understanding soil carbon cycling in arid and semiarid areas. In this study, we measured soil respiration using LI8100 Soil Respiration Observation System as well as air temperature, soil temperature, and soil moisture under three different land use types (<em>Haloxylon ammodendron</em> plantation, oasis cropland, and poplar plantation) in a desert-oasis region of Northwest China. The annual mean soil respiration was in order of<em>H.ammodendron</em> plantation (0.40 &mu;mol CO₂&middot;m^-2&middot;s^-1) < oasis cropland (1.61 &mu;mol CO₂&middot;m^-2&middot;s^-1) < poplar plantation (2.20 &mu;mol CO₂&middot;m^-2&middot;s^-1), which was mainly driven by soil organic carbon content. The relationship between soil temperature and soil respiration was fitted by the Lloyd-Taylor model. Soil respiration in all those ecosystems was more sensitive to lower temperature (non-growing season) than higher temperature (growing season). At yearround scale, soil respiration in the three ecosystems was positively correlated with soil temperature (<em>P</em><0.01). Furthermore, soil respiration in the <em>H. ammodendron</em> plantation and oasis cropland was positively correlated with soil moisture (<em>P</em><0.01). Soil respiration in the poplar plantation was positively correlated with soil moisture when it was below 6%, but was negatively correlated with soil moisture when it was above 6%. Our results provide basic data for soil carbon cycling in the desertoasis region.

应用静态箱&mdash;气相色谱法对鼎湖山南亚热带3种主要类型森林土壤呼吸（S+L和S）进行长达31个月的连续观测，结果表明：季风常绿阔叶林（BF）、针阔叶混交林（MF）和马尾松林（PF）凋落物对土壤呼吸年平均贡献率分别为27.82%、33.29%和36.35%，而且3个林型具有相同的季节动态特征，高峰期出现在雨季（4~9月），分别占全年贡献量的71.87%、61.89%和70.39%。土壤呼吸（S+L）与凋落物输入量的季节变化有极显著正相关性（P＜0.001）；土壤含水量与凋落物对土壤呼吸贡献的相关性均达到极显著水平（P＜0.001）；土壤温度与土壤呼吸通量呈显著的正相关关系，但与凋落物对土壤呼吸的贡献的关系并不明显；降雨天气凋落物对土壤呼吸贡献率分别为28.63%、38.20%和40.12%，显著高于晴朗天气。

Three main types of Soil respirations(S+L and S) in southern subtropical forests in Dinghushan biosphere reserve were consecutively being monitored over 31 months by the approach of static chamber-gas chromatograph techniques. Research shows that: annual mean contribution rates of litter-fall to soil respiration in the monsoon evergreen broadleaf forest (BF), mixed broadleaf-coniferous forest (MF) and coniferous(pine) forest (PF) reached 27.82%、33.29%和36.35% respectively; Moreover, all three types of forests displayed the same seasonal dynamic features with the peaks contributions of them were from April to September, which accounts for 71.87%、61.89% and 70.39% of annual total contributions of litterfall to soil respiration respectively. Soil respiration(S+L) had an obviously positive relationship with the seasonal changes of litter-fall input（P<0.001; And soil water content had a significant impact on the contribution of litter-fall to soil respiration in the three types of forests (P<0.001); Soil temperature had positive correlativity with soil respiration flux, though it has no distinctive relationship with contribution of litter-fall to soil respiration; the contribution ratios of litter-fall to soil respiration on rainy days were 28.63%、38.20% and 40.12% respectively, which were significantly higher than those in the sunny days in the three types of forests.

土壤呼吸是当前区域碳收支及全球变化研究中的一个热点问题。降雨作为一个重要的扰动因子, 对准确估算土壤呼吸具有重要影响, 这在干旱和半干旱地区尤为明显。尽管关于土壤呼吸对降雨响应过程与规律的研究已取得了较大进展, 但是对于其机制的解释仍然存在较大的争议, 集中体现在对“Birch效应” (降雨强烈激发土壤呼吸的现象)的解释上, 即到底是“底物供应改变机制”还是“微生物胁迫机制”在调控该过程。该文综述了土壤呼吸对降雨事件、降雨量及降雨格局的响应过程与规律; 阐述了土壤呼吸各组分对降雨响应的差异, 分析了雨后物理替代与阻滞、底物供应、根系和微生物活性、微生物群落结构与功能等一系列过程引起土壤呼吸改变的机制; 重点阐述了微生物对土壤水分波动的响应与适应机制。在此基础上提出了今后需重点关注的4个方面：1) “底物供应改变机制”与“微生物胁迫机制”的区分; 2)土壤呼吸各组分对降雨响应的差异;3)不同时空尺度上土壤呼吸对降雨响应的模拟与估算; 4)降雨带来的外援N和H+的作用。

<FONT face=Verdana>Soil respiration is an important issue in research on regional carbon budget and global change. Rainfall, which acts as an important disturbance to soil respiration, leads to large uncertainties in estimating carbon exchange between soil and the atmosphere, especially in arid and semiarid regions. Although significant progress on the response of soil respiration to rainfall has been made, considerable controversies on its mechanism still exist. There are two different mechanisms to interpret the “Birch effect”, which is characterized by a strong soil CO₂ emission soon after a rainfall event: “the substrate supply change mechanism” and “microbial stress mechanism”. We review progress in the study of the response of soil respiration to rainfall and summarize the responses of different components of soil respiration to the changes induced by rainfall, including physical replacement and blockage, substrate supply change, activity change of root system and microbes and changes in the structure and function of the microbial community. We also point out four important aspects to be considered in the future: 1) evaluating the function of “substrate supply change mechanism” and “microbial stress mechanism” to the “Birch effect”, 2) quantifying the response of soil respiration to rainfall based on different components, 3) modeling and estimating the response of soil respiration to rainfall on different temporal and spatial scales, and 4) evaluating the possible effects of N and H⁺ from rainfall on soil respiration.</FONT>