云南省元谋干热河谷的土壤抗旱力评价

根据土壤基本水分物理常数，将土壤水分蒸发划分为三个阶段。土壤水分累积蒸发量Ｑ与蒸发历时Ｔ具有：Ｑ＝ａＴ＾ｂ关系。不同土壤的蒸发能力不同，主要与土壤质地、结构等因素有关。同时不同土壤的抗旱力也有很大差异。土壤抗旱力由强至弱依次为：普通薄层土、变性燥红土、普通燥红土、表蚀干热的半干润变性土、表蚀燥红土。     

元江河谷燥红土的成因、特性及其改良利用

燥红土过去曾定名为热带稀树草原土、红棕壤,红褐色土和红棕色土等,对它的形成特点及理化性状,前人曾做过大量工作,但对燥红土的成因,特别是生物气候条件的影响,阐述得不多。     

安徽郎溪黄棕色土—红土二元结构土壤剖面的成因与长江流域第四纪晚期古气候演变

安徽宣郎广一带,黄棕色土-红土二元结构地貌十分常见。本文在郎溪选择了一个典型的黄棕色土-红土剖面,进行粒度组成和元素地球化学性状的研究,结果表明:(1)研究剖面上部黄棕色土的粒度组成和元素地球化学特征,与宣城、九江黄棕色土和镇江下蜀黄土十分一致,说明研究区域的黄棕色土确实与长江流域广泛分布的下蜀黄土同源。郎溪剖面粒度和元素地球化学特征的变化较均匀,尤其黄棕色土→埋藏红土(包括均质红土和网纹红土)间呈连续过渡,无沉积间断,表明埋藏红土的物源与黄棕色土和下蜀黄土相似,具典型的风积成因特性。(2)与黄棕色土相比,埋藏红土粒径偏细,风化成土作用显著增强。从埋藏红土逐渐过渡到黄棕色土,反映的可能是长江流域晚更新世初期,末次间冰期结束、末次冰期开始时的一次重大的古气候演变事件,但仍需确凿的年代学证据。     

侧向溢流堰控制泥沙的试验研究

横跨河床的砂防坝，势必存在限制鱼类活动的弊端。缝隙坝常因阻塞而失去作用。为此提出侧向溢流堰控制泥沙的设计方案。重点研究其分流作用、拦截泥沙作用。共设３个因素（堰长Ｌ、堰高Ｄ、堰宽Ｂ），１０个处理。研究结果表明：分流比Ｑ２／Ｑ０。与高深比Ｄ／ｈ没有相关关系。但在Ｄ／ｈ相同条件下，随Ｌ的增加，Ｑ２／Ｑ０。有增加的趋势。而Ｑ２／Ｑ０与Ｌ／Ｂ回归方程为Ｑ２／Ｑ０＝０．０５５Ｌ／Ｂ。排沙比Ｖ１／Ｖ０与Ｑ１／Ｑ０相关分析结果与Ｄ无关。从主槽排向侧槽的沙量取决于Ｌ。河床纵断变化为Ｌ越长，堰上跨越易冲刷，下游越易出现沉积。横断变化当Ｄ＝０时，堰区及侧槽有泥沙沉积；当Ｄ＝２ｃｍ时，在堰附近产生沉积。利用侧向溢流堰的分流作用，可以起到在主槽内控制泥沙作用。但在侧槽也存在泥沙沉积现象。因此，如何对堰长、堰高、及主、侧槽宽度进行设计，使泥沙只在主槽内沉积将是今后研究的课题。     

皖南第四纪红土伊利石结晶度值与风化强度的关系

对安徽宣城市宣州和郎溪两地第四纪红土黏土矿物组合和伊利石结晶度进行研究,探讨其对第四纪红土形成环境的指示意义。结果表明,两地第四纪红土黏土矿物的组合基本相似:剖面上部末次冰期下蜀黄土层(黄棕色土层)黏土矿物主要为伊利石、高岭石和2∶1型的蛭石;均质红土和网纹红土以伊利石和高岭石为主,无蛭石;网纹层下部出现伊利石-蒙脱石混层矿物。根据伊利石的X射线衍射(XRD)峰,获得伊利石结晶度(Illite crystallinity,IC)值,可以反映伊利石结晶程度。两地第四纪红土同类层次的IC值较接近。宣州和郎溪剖面黄棕色土的IC值平均为0.463,均质红土为0.599,网纹红土为0.726。全剖面样品IC值与风化强度指标呈显著负相关,充分说明红土IC值可有效地反映红土的风化强度。第四纪红土剖面从黄棕色土→均质红土→网纹红土,IC值升高,伊利石结晶变差,反映了红土风化强度增加,形成的气候环境更加湿热。     

红土严重裸露的里仁沟小流域治理及效益

渭源县里仁沟流域红土裸露面积占流域总面积的６０．６％，水蚀和红土泻溜等重力侵蚀严重。在治理中，突出综合作用，坚持工程措施和植物措施相结合，拦蓄利用梁坡径流稳定坡脚和沟床，雨季红土坡穴播沙棘、沙打旺等林草。经过五年连续治理，全流域累计完成基本农田６２８．７７ｈｍ￣２，造林５６２．６ｈｍ２，种草１５０．０７ｈｍ￣２，治理水土流失面积１３．４１ｋｍ￣２，其中红土治理面积６．２７ｋｍ￣２。土地利用和产业结构得到初步调整，人均收入由治理前的２０６．５１元增加到４０７．０９元，林草覆盖率由６．１％上升到４０．６％，年径流模数由３１２３８．６ｍ３／ｋｍ￣２降低到１１９２８．４ｍ３／ｋｍ￣２，年土壤侵蚀模数由５６００ｔ／ｋｍ￣２降低到１１６５．９ｔ／ｋｍ￣２。     

元谋干热河谷冲沟沟头土壤结构对入渗性能的影响

元谋干热河谷冲沟沟头土壤的渗透性是制约坡面径流,遏制沟头前进的重要因素,也间接影响着沟头土体崩塌方式。通过对元谋干热河谷区,3种典型土壤(燥红土、变性土和古红土)沟头表层土壤结构指标的测定和对入渗速率的野外定点观测,分析表层土壤结构特性及其分维特征对入渗过程的影响。结果表明:燥红土和变性土土壤结构要优于古红土;土壤颗粒和微团聚体分维数随着粉粘粒(<0.02mm)含量的增加而增大,随着砂砾(0.02～2mm)含量的增加而减小;孔隙分维数与颗粒分维和微团聚体分维呈负相关。3种土壤的入渗速率较低,用通用经验公式能够较好的模拟这3种土壤的入渗过程(R2>0.99)。表层土壤的非毛管孔隙和颗粒分维(D粒)对燥红土和古红土的初渗速率影响最大,毛管孔隙度、D粒和孔隙分维(D孔)对变性土的初渗速率影响最大,除了D粒的偏相关系数为负相关外,其余的影响因素都呈正相关;燥红土和变性土的毛管孔隙、D孔对稳渗速率影响最大,D孔和微团分维(D微)对古红土稳渗速率影响最大。     

成土母质对土壤团聚体形成的影响

成土母质对土壤团聚体数量及其稳定性的影响与不同母质所含无机胶体的差别有关，对浙江省八类母质发育的团聚体组成的研究表明：母质对土壤团聚体及其水稳定性影响顺次为玄武岩〉石灰岩、Ｑ２红土〉花岗岩、石英砂岩〉泥页岩〉紫砂岩〉红砂岩。其中母质对５￣１ｍｍ粒级的水稳性团聚体的影响最为显著。     

干湿循环下云南非饱和红土土—水特性研究

以云南红土为研究对象,以脱湿、吸湿引起的干湿循环作为控制条件,考虑初始干密度(1.20,1.25,1.30g/cm3)、初始含水率(30.0%,33.0%,36.0%)、预固结压力(0,50,100,200kPa)、过筛粒径(0.5,1.0,2.0mm)等影响因素,通过压力板仪法,研究干湿循环下云南非饱和红土的土—水作用特性。结果表明:干湿循环过程中,不同影响因素下红土的基质吸力随含水率的增大而减小,其土—水特征曲线呈直线型或"倒J"形,其脱湿变化过程可以分为快速脱湿、缓慢脱湿、稳定脱湿3个阶段,对应的吸湿变化过程也可以分为快速吸湿、缓慢吸湿、稳定吸湿3个阶段。相同基质吸力下,随初始干密度、初始含水率、预固结压力的增大,红土的含水率增大;随粒径的增大,红土的含水率减小。初始干密度、预固结压力、粒径(0.5mm除外)影响下的红土的土—水特征曲线可采用幂函数关系进行拟合,不同初始含水率、粒径0.5mm时的土—水特征曲线可采用线性函数关系进行拟合。红土脱湿过程的含水率高于吸湿过程的含水率,脱湿—吸湿过程中的土—水特征曲线存在滞后现象,其实质在于干湿循环作用下红土具有孔隙效应、瓶颈效应、角度效应的综合结果。     

降雨作用下云南省红土抗剪强度与坡面侵蚀模数的关系

[目的]揭示降雨作用下云南省红土的含水率、干密度、抗剪强度、坡面侵蚀模数之间的关系,为进一步研究云南省红土的侵蚀机理提供理论依据。[方法]运用人工模拟降雨及土槽模型试验、土工试验及相关理论分析相结合的研究方法。[结果](1)研究区红土黏聚力随含水率的变化呈二次曲线关系,且在最优含水率附近存在极大值。红土内摩擦角随含水率的变化接近于线性关系,且随含水率的增大而减小。当干密度为1.0,1.1,1.2,1.3,1.4g/cm3时,黏聚力与含水率的相关系数R2最小为0.754,最大为0.934;内摩擦角与含水率的相关系数R2最小为0.944,最大为0.996。(2)红土黏聚力和内摩擦角随干密度的变化接近于线性关系;当含水率一定时,二者随干密度增大呈增加的趋势。(3)在试验含水率条件下,红土抗剪强度随含水率的增加而减小,当含水率超过最优含水率后减小的幅度尤为明显;抗剪强度随干密度的增加而增大。(4)降雨结束后,不同干密度的红土坡面侵蚀模数与红土抗剪强度呈二次曲线关系,相关系数R2达0.988。[结论]坡面红土雨后抗剪强度与坡面侵蚀模数之间存在较好的相关关系,可用坡面红土的雨后抗剪强度估算坡面侵蚀量。     

西安地区全新世气候变化与土壤侵蚀研究

为了揭示西安地区全新世环境变化和黄土地层的侵蚀期,利用野外调查和化学分析等方法,研究了西安地区全新世黄土与古土壤发育时的气候变化和不同气候阶段的土壤侵蚀。通过野外调查,在西安白鹿塬区发现了在黄土塬区很少见到全新世中期古土壤分为3个层次,整个全新世黄土剖面可分为5层,表明黄土塬区全新世气候变化与沙尘暴活动与河谷地区一样可分为5个阶段。土层氧化物、微量元素、CaCO3含量和磁化率测定结果显示,西安白鹿塬区全新世8 500~6 000年和5 000~3 100年古土壤发育时较10 000~8 500年、6 000~5 000年和3 100年以来的黄土发育时夏季风活动强,降水量多,气候湿润,沙尘暴活动弱。中全新世8 500~6 000年间发育的S02古土壤中Fe2O3和Al2O3有一定富集,该层土壤类型相当于黄棕壤,指示当时年平均降水量较现今多150 mm左右。虽然沙尘暴活动很弱的间冰期是黄土地层理论上的侵蚀期,但是实际上这一时期的土壤侵蚀很弱。全新世黄土的侵蚀主要发生在气候冷干时期,不是发生在温湿时期。全新世中期6 000~5 000年间的黄土侵蚀率一般大于堆积率,使得广大地区全新世中期的薄层黄土在绝大多数地区受到侵蚀而消失。全新世中期薄层黄土发育时气候变冷干引起的植被退化是当时土壤侵蚀加强和出现侵蚀期的原因。     

Winter soil CO2 efflux and its contribution to annual soil respiration in different ecosystems of a forest-steppe ecotone, north China

Most soil respiration measurements are conducted during the growing season. In tundra and boreal forest ecosystems, cumulative winter soil CO₂ fluxes are reported to be a significant component of their annual carbon budgets. However, little information on winter soil CO₂ efflux 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 CO₂ efflux to climate changes. In this study we measured winter soil CO₂ efflux 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 CO₂ effluxes were 0.15-0.26 μmol m⁻² s⁻¹ and 2.65-4.61 μmol m⁻² s⁻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 Q₁₀ and 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 CO₂ efflux ranged from 394.76 g C m⁻² to 973.18 g C m⁻² using observed ecosystem-specific response equations between soil respiration and soil temperature. Estimates ranged from 424.90 g C m⁻² to 784.73 g C m⁻² by 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 CO₂ efflux 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 CO₂ efflux continues throughout the winter and winter soil respiration is an important component of annual CO₂ efflux.     

Evaluating the impacts of incubation procedures on estimated Q10 values of soil respiration

A reliable determination of the response of soil organic carbon decomposition to temperature is critical in the context of global warming. However, uncertainties remain in estimated temperature sensitivity of soil respiration, which may be partly due to different experimental conditions. To investigate the possible effects of laboratory incubation procedures on estimated Q₁₀ value, soil samples taken from various ecosystems were incubated under changing temperature with different experimental conditions or procedures: 1) different rate of temperature change; 2) different intervals of temperature change; 3) equilibration time after temperature change; 4) the duration of chamber closure and 5) the size of incubated soil sample. The results indicated that respiration rate was affected by experimental procedures. The respiration rate of soil samples containing high concentration of organic carbon decreased quickly if the soil container sealed longer than 2 h. Estimated Q₁₀ values across all soils ranged from 1.56 to 2.70, with respect to the effects of incubation procedures. Temperature rate change, equilibration time, the duration of chamber closure and soil sample size had no effect on estimated Q₁₀ values of soil respiration. However, Q₁₀ values derived from temperature changing intervals of 2 and 7 °C were significantly different, despite the fact that the exponential function fitted well for the relationship between respiration rate and temperature for both intervals. The results of these experiments suggested that incubation procedures have different effects on measured soil respiration and estimated Q₁₀ values. For soil incubations of short-duration, the effects of incubation procedures on soil respiration and estimated Q₁₀ values based on respiration rate should be appropriately tested with experimental setting-up, and estimating Q₁₀ values with few temperatures should be avoided.     

Temperature sensitivity of soil respiration is affected by prevailing climatic conditions and soil organic carbon content: A trans-China based case study

Understanding the spatial variation of temperature sensitivity (i.e. Q₁₀) of soil respiration (R_s) and its controlling factors, is critical to improve the precision of carbon budget estimations at regional scales. In this study, data from 2-3 continuous years of R_s measurements over 15 ecosystems of ChinaFLUX were summarized to analyze the response of R_s to soil temperature. Moreover, we improved our dataset by collecting previously published Q₁₀ values from 34 ecosystems in China. The ecosystems studied were located in the main climatic zones of China, spanning from alpine via temperate to tropical. Spatial variations of Q₁₀ and its controlling factors were analyzed. The results showed that soil temperature at a 5 cm depth satisfactorily explained the seasonal variations in R_s of the 15 ChinaFLUX ecosystems (R² varying from 0.37 to 0.83). Based on the overall data, the Q₁₀ values of R_s in China ranged from 1.28 to 4.75. The spatial variations in Q₁₀ were primarily determined by soil temperature during measurement periods, soil organic carbon (SOC) content, and ecosystem type. Ecosystems in colder regions and with higher SOC content had relatively higher Q₁₀ values. Moreover, ecosystems of different vegetation types showed different Q₁₀ values. A temperature- and SOC-dependent function for Q₁₀ is suggested, which could be a valuable reference for improving the regional-scale models of R_s and ecosystem carbon cycles.     

古土壤地球化学的某些问题——黄土风化过程中元素的变化

对黄土中埋藏古土壤的研究有过许多报道^[2,5,8].但对黄土风化过程中元素的变化讨论则不多.笔者是在近年来对陕西洛川黄土剖面工作的基础上,讨论了不同类型古土壤中元素的含量与分布,古土壤剖面中元素的变化.并将古土壤的化学组成与黄土母质进行比较,进而论述了在古气候变迁的影响下,黄土剖面中元素迁移、积聚的地球化学特征.这对探讨黄土的堆积环境和生物气候条件的演变,以及地层划分等均有十分重要意义.     

Temperature sensitivity of respiration differs among forest floor layers in a Pinus resinosa plantation

Decomposer microorganisms contribute to carbon loss from the forest floor as they metabolize organic substances and respire CO₂. In temperate and boreal forest ecosystems, the temperature of the forest floor can fluctuate significantly on a day-to-night or day-to-day basis. In order to estimate total respiratory CO₂ loss over even relatively short durations, therefore, we need to know the temperature sensitivity (Q₁₀) of microbial respiration. Temperature sensitivity has been calculated for microbes in different soil horizons, soil fractions, and at different depths, but we would suggest that for some forests, other ecologically relative soil portions should be considered to accurately predict the contribution of soil to respiration under warming. The floor of many forests is heterogeneous, consisting of an organic horizon comprising a few more-or-less distinct layers varying in decomposition status. We therefore determined at various measurement temperatures the respiration rates of litter, F-layer, and H-layer collected from a Pinus resinosa plantation, and calculated Q₁₀ values for each layer. Q₁₀ depended on measurement temperature, and was significantly greater in H-layer than in litter or F-layer between 5 and 17 °C. Our results indicate, therefore, that as the temperature of the forest floor rises, the increase in respiration by the H-layer will be disproportionate to the increase by other layers. However, change in respiration by the H-layer associated with change in temperature may contribute minimally or significantly to changes of total forest floor respiration in response to changes in temperature depending on the depth and thickness of the layer in different forest ecosystems.     

Influence of warming and enchytraeid activities on soil CO2 and CH4 fluxes

To determine the sum of ‘direct’ and ‘indirect’ effects of climatic change on enchytraeid activity and C fluxes from an organic soil we assessed the influence of temperature (4, 10 and 15 °C incubations) on enchytraeid populations and soil CO₂ and CH₄ fluxes over 116 days. Moisture was maintained at 60% of soil dry weight during the experimental period and measurements of enchytraeid biomass and numbers, and CO₂ and CH₄ fluxes were made after 3, 16, 33, 44, 65, 86 and 116 days. Enchytraeid population numbers and biomass increased in all temperature treatments with the greatest increase produced at 15 °C (to over threefold initial values by day 86). Results also showed that enchytraeid activity increased CO₂ fluxes by 10.7±4.5, 3.4±4.0 and 26.8±2.6% in 4, 10 and 15 °C treatments, respectively, with the greatest CO₂ production observed at 15 °C for the entire 116 day incubation period (P<0.05). The soil respiratory quotient analyses at lower temperatures (i.e. 4-10 °C) gave a Q₁₀ of 1.7 and 1.9 with and without enchytraeids, respectively. At temperatures above 10 °C (i.e. 10-15 °C) Q₁₀ significantly increased (P<0.01) and was 25% greater in the presence of enchytraeids (Q₁₀=3.4) than without (Q₁₀=2.6). In contrast to CO₂ production, no significant relationships were observed between net CH₄ fluxes and temperature and only time showed a significant effect on CH₄ production (P<0.01).Total soil CO₂ production was positively linked with enchytraeid biomass and mean soil CO₂-C production was 77.01±6.05 CO₂-C μg mg enchytraeid tissue⁻¹ day⁻¹ irrespective of temperature treatment. This positive relationship was used to build a two step regression model to estimate the effects of temperature on enchytraeid biomass and soil CO₂ respiration in the field. Predictions of potential CO₂ production were made using enchytraeid biomass data obtained in the field from two upland grassland sites (Sourhope and Great Dun Fell at the Moor House Nature Reserve, both in the UK). The findings of this work suggest that a 5 °C increase in atmospheric temperature above mean ambient temperature could have the potential to produce a significant increase in enchytraeid biomass resulting in a near twofold increase in soil CO₂ release from both soil types. The interaction between temperature and soil biology will clearly be an important determinant of soil respiration responses to global warming.     

Relationship between soil CO2 concentrations and forest-floor CO2 effluxes

To better understand the biotic and abiotic factors that control soil CO₂ efflux, we compared seasonal and diurnal variations in simultaneously measured forest-floor CO₂ effluxes and soil CO₂ concentration profiles in a 54-year-old Douglas fir forest on the east coast of Vancouver Island. We used small solid-state infrared CO₂ sensors for long-term continuous real-time measurement of CO₂ concentrations at different depths, and measured half-hourly soil CO₂ effluxes with an automated non-steady-state chamber. We describe a simple steady-state method to measure CO₂ diffusivity in undisturbed soil cores. The method accounts for the CO₂ production in the soil and uses an analytical solution to the diffusion equation. The diffusivity was related to air-filled porosity by a power law function, which was independent of soil depth. CO₂ concentration at all depths increased with increase in soil temperature, likely due to a rise in CO₂ production, and with increase in soil water content due to decreased diffusivity or increased CO₂ production or both. It also increased with soil depth reaching almost 10 mmol mol⁻¹ at the 50-cm depth. Annually, soil CO₂ efflux was best described by an exponential function of soil temperature at the 5-cm depth, with the reference efflux at 10 °C (F₁₀) of 2.6 μmol m⁻² s⁻¹ and the Q₁₀ of 3.7. No evidence of displacement of CO₂-rich soil air with rain was observed.Effluxes calculated from soil CO₂ concentration gradients near the surface closely agreed with the measured effluxes. Calculations indicated that more than 75% of the soil CO₂ efflux originated in the top 20 cm soil. Calculated CO₂ production varied with soil temperature, soil water content and season, and when scaled to 10 °C also showed some diurnal variation. Soil CO₂ efflux and concentrations as well as soil temperature at the 5-cm depth varied in phase. Changes in CO₂ storage in the 0–50 cm soil layer were an order of magnitude smaller than measured effluxes. Soil CO₂ efflux was proportional to CO₂ concentration at the 50-cm depth with the slope determined by soil water content, which was consistent with a simple steady-state analytical model of diffusive transport of CO₂ in the soil. The latter proved successful in calculating effluxes during 2004.     

Strong temperature dependence and no moss photosynthesis in winter CO2 flux for a Kobresia meadow on the Qinghai-Tibetan plateau

We examined the CO₂ exchange of a Kobresia meadow ecosystem on the Qinghai-Tibetan plateau using a chamber system. CO₂ efflux from the ecosystem was strongly dependence on soil surface temperature. The CO₂ efflux-temperature relationship was identical under both light and dark conditions, indicating that no photosynthesis could be detected under light conditions during the measurement period. The temperature sensitivity (Q₁₀) of the CO₂ efflux showed a marked transition around −1.0 °C; Q₁₀ was 2.14 at soil surface temperatures above and equal to −1.0 °C but was 15.3 at temperatures below −1.0 °C. Our findings suggest that soil surface temperature was the major factor controlling winter CO₂ flux for the alpine meadow ecosystem and that freeze-thaw cycles at the soil surface layer play an important role in the temperature dependence of winter CO₂ flux.     

Microbial decomposition of skeletal muscle tissue (Ovis aries) in a sandy loam soil at different temperatures

A laboratory experiment was conducted to determine the effect of temperature (2, 12, 22 °C) on the rate of aerobic decomposition of skeletal muscle tissue (Ovis aries) in a sandy loam soil incubated for a period of 42 days. Measurements of decomposition processes included skeletal muscle tissue mass loss, carbon dioxide (CO₂) evolution, microbial biomass, soil pH, skeletal muscle tissue carbon (C) and nitrogen (N) content and the calculation of metabolic quotient (qCO₂). Incubation temperature and skeletal muscle tissue quality had a significant effect on all of the measured process rates with 2 °C usually much lower than 12 and 22 °C. Cumulative CO₂ evolution at 2, 12 and 22 °C equaled 252, 619 and 905 mg CO₂, respectively. A significant correlation (P<0.001) was detected between cumulative CO₂ evolution and tissue mass loss at all temperatures. Q₁₀s for mass loss and CO₂ evolution, which ranged from 1.19 to 3.95, were higher for the lower temperature range (Q₁₀(2-12 °C)>Q₁₀(12-22 °C)) in the Ovis samples and lower for the low temperature range (Q₁₀(2-12 °C)<Q₁₀(12-22 °C)) in the control samples. Metabolic quotient and the positive relationship between skeletal muscle tissue mass loss and cumulative CO₂ evolution suggest that tissue decomposition was most efficient at 2 °C. These phenomena may be due to lower microbial catabolic requirements at lower temperature.