东北寒温带永久冻土区森林沼泽湿地生态系统碳储量

摘 要 湿地在全球碳循环中具有重要作用，但目前湿地碳储量估算仍存在诸多不确定性。利用相对生长方程与碳/氮分析仪测定法，同步测定寒温带大兴安岭永久冻土区沿过渡带环境梯度依次分布的7种典型天然沼泽类型(草丛沼泽-C、灌丛沼泽-G、毛赤杨沼泽-M、白桦沼泽-B和落叶松苔草沼泽-LT、落叶松藓类沼泽-LX、落叶松泥炭藓沼泽-LN)的生态系统碳储量(植被和土壤)、植被净初级生产力与年净固碳量，定量评价各沼泽类型的生态系统碳库及植被固碳能力，并揭示两者沿过渡带环境梯度的空间分布规律性。结果表明：①其植被碳储量(3.60~62.18 t·hm-2)沿过渡带环境梯度呈先上升后降低的偏态型分布趋势；②土壤碳储量(179.47~320.81 t·hm-2)呈森林沼泽(M除外)与灌丛沼泽显著高于C (56.4%~78.8%，P<0.05)和M (32.0%~50.9%，P<0.05)的变化规律性；③生态系统碳储量(183.07~347.14 t·hm-2)也呈现森林沼泽(M除外)与灌丛沼泽显著高于C (64.0%~89.6%，P<0.05)和M (28.1%~48.1%，P<0.05)的变化规律性，但森林沼泽土壤碳储量占比(82.1%~96.4%)要低于C和G (98.0%~98.3%)；④植被净初级生产力(6.76~11.22 t·hm-2·a-1)和年净固碳量(2.97~5.37 t·hm-2·a-1)均呈现森林沼泽(LN除外)显著高于C和G (26.9%~61.4%和30.5%~66.0%；38.6%~77.2%和41.4%~80.8%，P<0.05)的变化规律性。因此，寒温带永久冻土区各类型沼泽湿地的生态系统碳储量均相对较低(仅相当于北方泥炭地碳储量(390~1 395 t·hm-2)下限值的46.9%~89.0%)，且沿过渡带环境梯度总体上呈递增趋势；森林沼泽(LN除外)的植被固碳能力强于灌丛沼泽与草丛沼泽，且前者略高于全球陆地植被年均净固碳量估计值(4.1 t·hm-2·a-1)，而后两者仅相当于其3/4。     

若尔盖高原退化湿地土壤有机碳储量

为了定量评价若尔盖高原泥炭沼泽湿地退化的碳储存潜力,研究通过土壤剖面法,收集了3个样点的泥炭沼泽湿地土壤样品(原始泥炭地0—200cm、中度退化沼泽湿地0—100cm和重度退化泥炭地0—100cm)。研究表明:(1)中度退化沼泽湿地(1.11±0.18g/cm~3)和重度退化泥炭地(0.72±0.04g/cm~3)土壤容重平均值较原始泥炭地增加了251.8%和129.7%;中度退化沼泽湿地(46.18±6.61g/kg)和重度退化泥炭地(87.37±6.36g/kg)土壤有机碳含量平均值较原始泥炭地降低了74.2%和51.1%。(2)土层深度为0—100cm时,原始泥炭地土壤有机碳储量较中度退化沼泽湿地(384.73±95.57t/hm~2)显著高了47.0%,而与重度退化泥炭地(518.39±33.07t/hm~2)土壤有机碳储量无显著差异;当原始泥炭地有机层增加到0—200cm后,中度退化沼泽湿地和重度退化泥炭地土壤有机碳储量较原始泥炭地(1 088.17±172.84t/hm~2)降低了64.6%和52.4%,退化湿地土壤有机碳储量的降低可能主要是土壤有机碳含量降低的原因。尽管退化湿地土壤有机碳储量下降,但仍是中国(102.89t/hm~2)和全球(116.56t/hm~2)陆地土壤有机碳储量的3~5倍,该研究可为保护与恢复若尔盖高原湿地提供科学依据。     

中国陆地土壤有机碳储量估算及其不确定性分析

土壤有机碳密度和储量的统计对于研究土壤碳循环至关重要.为提高土壤有机碳密度和储量的估算精度,明晰导致估算存在不确定性的内在原因,根据第二次土壤普查资料,采用两种方式、两种土层厚度、两个公式以及3种碳密度取值方法估算了中国土壤有机碳储量,结果表明,中国陆地土壤有机碳储量大致在50.6～154.0 Pg(1 Pg=1015 g)之间,平均储量为(102.3±51.7)Pg;估算的不确定性处于25.5%～30.4%之间.中国陆地土壤有机碳储量估算结果差异以及不确定性主要来源于以下几个方面:碳密度的取值方法不同,估算深度不一致,计算公式不统一,基础数据不一样以及制图尺度差异.本文研究结果认为基于GIS数字土壤图,采用标准1 m厚度土层,运用不考虑大于2 mm砾石含量的碳密度计算公式以及分土层累计计算法是估算中国陆地土壤有机碳储量最优方法.     

长江口典型湿地植被储碳、固碳功能研究——以崇明东滩芦苇带为例

湿地生态系统具有很强的储碳、固碳能力,在全球碳循环中占有重要地位.为了解长江口典型湿地芦苇(Phragmites australis)的储碳、固碳情况,通过实地调研与实验室测定相结合的方法,研究了崇明东滩芦苇带湿地植被的生物量和初级生产力,并测算了其碳储量和固碳能力.结果表明:长江口典型芦苇带湿地植被的碳储量较大,为2.66～5.74 kg·m-2,平均4.02 kg·m-2,且地下部分的生物现存量大于地上部分,地下/地上生物量比率为2.33～3.64,平均2.96,碳储量是地上部分的近3倍;长江口典型芦苇带湿地具有很强的固碳能力,达1.11～2.41 kg·m-2·a-1,是全国陆地植被平均固碳能力的2.3～4.9倍,全球植被平均固碳能力的2.7～5.9倍.     

不同干扰程度下黄河三角洲植被群落有机碳分布特征

为研究不同干扰程度下滨海湿地有机碳分布特征,选择黄河三角洲干扰程度较小的一千二管理站和黄河口管理站及干扰程度较大的东营港和五号桩4个研究区,对不同植被群落下的土壤有机碳含量、密度及单位面积储量进行研究。结果表明:植被生长初期(5月)一千二管理站、东营港、五号桩和黄河口管理站土壤有机碳含量、有机碳密度以及单位面积有机碳储量分别为3.504,3.433,3.698,3.815g/kg、4.84,4.58,5.02,5.56kg/m2和4 237.00,3 807.42,4 272.77,4 917.63t/km2。植被生长旺期(8月份)一千二管理站、东营港、五号桩和黄河口管理站土壤有机碳含量、有机碳密度以及单位面积有机碳储量分别为3.90,3.63,3.45,3.62g/kg、5.32,4.83,4.46,5.25kg/m2和4 588.02,4 010.10,3 614.95,4 623.12t/km2。人为活动干扰较大的五号桩和东营港地区,有机碳含量、有机碳密度以及单位面积有机碳储量较小;光滩有机碳含量比有植被生长的湿地低;互花米草湿地有机碳含量和有机碳密度在植被生长初期高于其他湿地类型,但这种优势在生长旺期不显著,与黄河口管理站和一千二管理站芦苇湿地单位面积有机碳储量相比较,互花米草湿地单位面积有机碳储量要低。由此可见,人为干扰对滨海湿地有机碳含量、密度及储量产生较大的影响,保护湿地完整性对于减少碳排放、维护滨海湿地的碳汇功能具有重要的作用。     

徐州市石灰岩山地不同植被恢复模式的碳储量

[目的]研究不同造林模式的碳储量,为区域碳汇森林的营建提供理论依据。[方法]以江苏省徐州市石灰岩山地分布普遍的6种植被恢复模式为研究对象,对其碳储量及其分配格局进行了计算。[结果]6种植被恢复模式总碳储量的变化范围在28.379~46.561t/hm2之间,表现为侧柏(Platyclatdus orientalis)×梧桐(Firmiana simplex)侧柏×女贞(Ligustrum lucidum)侧柏×枫香(Liquidambar formosana)侧柏侧柏×栾树(Koelreuteria paniculata)侧柏×黄栌(Cotinus coggygria)。土壤碳储量占总碳储量的54.333%~78.290%。植被碳储量占总碳储量的20.213%~44.414%。枯落物碳储量占总碳储量的0.582%~3.897%。[结论]土壤碳储量是不同植被恢复模式总碳储量的主体。保护石灰岩山地现有土层,防治水土流失及频繁的人为扰动对于维持土壤碳储量具有重要作用。加强对侧柏的养护管理,配置适宜的阔叶树种可以有效地增加植被的固碳潜力。     

大庆地区植被和土壤碳氮储量的估算

利用1978年MSS多光谱数据、2008年中国资源卫星数据和全国第二次土壤普查数据,对黑龙江省土壤退化典型地区大庆地区的植被和土壤碳氮储量进行了估算。结果表明:大庆地区的植被平均碳密度1978年为0.58kg/m2,2008年为0.67kg/m3;土壤平均碳氮密度分别为(9.26±1.73)kg/m3和(0.62±0.17)kg/m3,土地覆被平均土壤碳氮密度分别为(8.10±2.34)kg/m3和(0.50±0.11)kg/m3。1978和2001年植被碳储量分别为(9.38×106)t和(10.40×106)t,30年间植被碳储量增加了(1.02×106)t;全区土壤总碳量为(187.18±34.95)×106t,总氮量为(125.84±33.66)×105t;全区土地覆被土壤总碳量为(163.68±47.34)×106t,总氮量为(102.00±22.55)×105t。大庆地区的植被和土壤平均碳密度都低于中国的平均水平。     

黄土高原子午岭森林碳储量与碳密度研究

基于样地林分调查与室内分析,运用清查平均生物量法和林木相对生长模型,研究了黄土高原子午岭林区3种森林碳储量及碳密度空间分布特征。结果表明:研究区森林生态系统植被含碳率变化范围为0.331 6～0.553 2 g/g;变异系数介于2%～14%,而枯落层含碳率为0.294 8～0.335 9 g/g;3种林地平均碳密度:柴松林为238.22 t/hm2,辽东栎林为235.75 t/hm2,油松林为191.58 t/hm2,柴松林及辽东栎林碳密度约是油松林的1.24倍;从研究空间尺度上土壤层植被层枯落层,其碳密度分别为105.21,88.11,28.53 t/hm2,其中植被层各分层碳密度大小差异显著,而土壤层碳密度随着土壤深度的增加而递减;3种森林生态系统有机碳库总储碳量为31.70 Tg,其中土壤层碳储量占整个碳库的49%,是植被层和枯落层碳储量的1.3倍和3.5倍,且碳储量空间分布呈现出:土壤层乔木层枯枝落叶层灌木层草本层。     

盱眙县墨西哥柏人工林含碳率与碳储量研究

选取盱眙县墨西哥柏人工林为研究对象,对其灌木层、草本层、枯枝落叶层、土壤层进行了碳储量研究。结果表明:灌木层枝、干、叶、根的含碳率依次48.92%,48.49%,49.74%和48.04%,器官含碳率大小表现为C_叶 > C_枝 > C_干 > C_根,草本层是地上部分含碳率大于地下部分含碳率,枯枝落叶层的含碳率表现为C_叶 > C_枝,土壤层的含碳率随着土壤深度的增加而降低,0—10 cm和10—20 cm土层之间土壤含碳率的差异性显著。墨西哥柏人工林生态系统现存碳储量67.31 t/hm²,其中灌木层1.21 t/hm²,占总碳储量的1.8%;草本层0.08 t/hm²,占总碳储量的0.12%;枯枝落叶层0.02 t/hm²,占总碳储量的0.03%;土壤层66 t/hm²,占总碳储量的98.05%,可见碳储量主要集中在土壤层中。     

土壤数据源和制图比例尺对旱地土壤有机碳储量估算的影响

明确不同来源土壤剖面数据建立的大、中、小系列制图比例尺对旱地有机碳储量估算的影响对于全球碳循环研究具有重要意义。以江苏北部(简称"苏北地区")3.9×106多hm2旱地为例,系统分析了我国目前常用《县级土种志》、《地级市土种志》、《省级土种志》和《中国土种志》中记录的土壤剖面数据分别建立的1∶5万、1∶25万、1∶50万、1∶100万、1∶400万和1∶1 000万数据库对有机碳储量估算的影响。结果表明,与数据最详细、记录有983个土壤剖面的《县级土种志》1∶5万尺度有机碳密度和储量相比,其他土壤数据源建立的不同制图尺度数据库相对偏差分别在1.94%~23.53%与0.02%~22.86%之间,T检验表明大多数制图尺度土壤数据库的估算结果与《县级土种志》1∶5万尺度之间存在极显著差异(p0.001),这说明在今后国家或区域尺度土壤有机碳储量估算中选择适宜的土壤数据源和制图尺度是非常重要的。     

Examining soil organic carbon in the mountainous peat swamps of the Zoigê Plateau in China's Qinghai-Tibet Plateau

Mountainous peatlands are one of the most important terrestrial ecosystems for carbon storage and play an important role in the global carbon cycle. An insight into the carbon cycle of peat swamps located in mountainous regions can be obtained by studying the distribution of soil organic carbon (SOC) and its relationships with environmental factors. This study focused on the development conditions of peat swamps in the Gahai wetlands, located on the Zoigê Plateau, China, with four different altitudinal gradients as experimental sample sites. The distribution of SOC and its relationship with environmental factors were analysed through vegetation surveys and a generalized additive model (GAM). The results show that with increasing altitude, soil temperature decreased while the soil pH and bulk density initially decreased then increased. On the contrary, the topographic wetness index (TWI), SOC content, above-ground biomass and litter count initially increased then decreased. The SOC content of the 0–30 cm soil layer was in the range 226–330 g·kg⁻¹ (coefficient of variation (CV) = 21.4%), and the 30–60 cm layer was 178–257 g·kg⁻¹ (CV = 17.5%) and was significantly correlated (p < .05) with above-ground biomass and litter count. Meanwhile, the SOC content in the 60–90 cm soil layer was in the range 132–167 g·kg⁻¹ (CV = 9.2%) with a significant correlation (p < .05) with soil temperature, pH, bulk density and topographic moisture index. The study showed that the SOC content exhibited more pronounced spatial patterns with increasing altitude, with the peak value in the shallow soil layer appearing in lower elevation areas compared with the deep soil layer. The level of variation changed from medium to low, reflecting the stable mechanism for maintaining SOC within the heterogeneous peat swamp environment.     

尕海泥炭地退化过程中土壤渗透特征的变化

由于恶劣的气候条件和过度的放牧、修建公路等因素,尕海泥炭湿地退化严重,泥炭地质量和生态作用持续下降。本研究采用空间分布代替时间序列的方法,对该区域4种不同退化程度下泥炭湿地土壤渗透性能的变化进行分析研究,从而进一步评价与揭示退化过程中泥炭地的生态功能。结果表明:在前35 min,泥炭地土壤入渗速率曲线在各土壤分层中的变化情况不一;0~10 cm和20~40 cm土层土壤入渗速率曲线变化稳定且都表现为未退化的优于退化土壤;而10~20 cm土层土壤入渗速率曲线变化复杂多变,无明显规律。0~40 cm泥炭土中,植被退化对各层土壤渗透特征的影响不一,在0~10 cm土层,植被未退化土壤的初渗率、稳渗率、平均渗透速率、渗透系数和渗透总量与其他退化土壤渗透特征差异性显著;10~20 cm土层,未退化的土壤稳渗率、渗透速率、渗透系数与渗透量随着植被的退化程度呈“∽”形态波动变化;0~40 cm土层,土壤稳渗率、平均渗透速率、渗透系数和渗透总量均随着植被的退化,呈现出逐级递减的规律。土壤平均渗透速率与土壤孔隙度呈一定的正显著相关,而与土壤初始含水量之间无明显的相关性。保护高寒泥炭地生态系统,对于尕海畜牧业可持续发展和我国陆地生态系统碳库具有极重要的意义。     

Estimating the carbon stock of a blanket peat region using a peat depth inference model

At the global scale peatlands are an important soil organic carbon (SOC) pool. They sequester, store and emit carbon dioxide and methane and have a large carbon content per unit area. In Ireland, peatlands cover between 17% and 20% of the land area and contain a significant, but poorly quantified amount of SOC. Peatlands may function as a persistent sink for atmospheric CO₂. In Ireland the detailed information that is required to calculate the peatland SOC pool, such as peat depth, area and carbon density, is inconsistent in quality and coverage. The objective of this research was to develop an improved method for estimating the depth of blanket peat from elevation, slope and disturbance data to allow more accurate estimations of the SOC pool for blanket peatlands. The model was formulated to predict peat depth at a resolution of 100 ha (1 km²). The model correctly captured the trend and accounted for 58 to 63% of the observed variation in peat depth in the Wicklow Mountains on the east coast of Ireland. Given that the surface of a blanket peatland masks unknown undulations at the mineral/peat interface this was a successful outcome. Using the peat depth model, it was estimated that blanket peatland in the Wicklow Mountains contained 2.30 Mt of carbon. This compares to the previously published values ranging from 0.45 Mt C to 2.18 Mt C.     

洞庭湖湿地植被系统的碳贮量及其分配

利用生物量调查和实验数据.对洞庭湖湿地植被生态系统的碳密度、碳贮量及其分配进行研究.结果表明:乔木层植被碳密度为15.607～40.501 t/hm~2,草本层植被为5.906～21.632 t/hm~2.水生植物植被1.460～3.492 t/hm~2,平均14.954 t/hm~2比温带地区湿地植物碳密度高;未受干扰草甸土壤碳密度为260.510 t/hm~2,每年收获产品草甸是185.492 t/hm~2,林地234.513 t/hm~2,水生植物土壤为206.882 t/hm~2,低于全国湿地土壤平均值.碳贮量分配中.植被层、凋落物层和土壤层的碳贮量分别占各植被类型系统碳的总贮量的0.47%～14.69%,0.29%～1.10%和84.54%～99.53%.每年收获部分产品的草甸土壤碳密度只有未受人为干扰草甸的71.2%,原生草本植物草地改造成林地后,6年的时间,土壤的碳密度减少了10%.因此,控制人为干扰,防止湿地破碎化、保护好湿地、保证湿地的固碳潜力,是湿地管理中应该优先考虑的问题.     

长白山森林土壤有机碳库大小及周转研究

主要分析不同森林植被下有机碳的分解动态和土壤碳库各组分大小、周转时间。结果表明：土壤样品培养90天，CO2累计释放量表层大致为1723～5065mg／kg、下层大致为178～642mg／kg。分解速率总的趋势是前期快，后期慢，表层明显大于下层。大小顺序为：冷杉林〉针阔混交林和阔叶林〉针叶林。在不同植被下的表层和下层土壤中，活性碳占总有机碳的0．54％～1．67％，0．45％～5．48％．平均驻留时间为11～56天、60～88天；缓效性碳占总有机碳的23．0％～63．3％，33．2％～72．2％，平均驻留时间为4～70年、24～161年；惰效性碳占总有机碳的35．5％～75．5％．26．0％～65．%。表层土壤的总有机碳、活性碳、缓效性碳和惰效性碳含量都明显大于下层。凋落物的化学组成主要决定活性碳库、缓效性碳库含量，土壤的粘粒含量等性质主要决定惰效性碳库含量。     

Scots pine litter decomposition along drainage succession and soil nutrient gradients in peatland forests, and the effects of inter-annual weather variation

Peatlands form a large carbon (C) pool but their C sink is labile and susceptible to changes in climate and land-use. Some pristine peatlands are forested, and others have the potential: the amount of arboreal vegetation is likely to increase if soil water levels are lowered as a consequence of climate change. On those sites tree litter dynamics may be crucial for the C balance. We studied the decomposition of Scots pine (Pinus sylvestris L.) needle and root litter in boreal peatland sites representing gradients in drainage succession (succession following water level drawdown caused by forest drainage) and soil nutrient level during several years of varying weather conditions. Neither gradient had an unambiguous effect on litter mass loss. Mass loss over 2 years was faster in undrained versus drained sites for both needle litter, incubated in the moss layer, and fine root litter, incubated in 0-10 cm peat layer, suggesting moisture stress in the surface layers of the drained sites limited decomposition. Differences among the drained sites were not consistent. Among years, mass loss correlated positively with precipitation variables, and mostly negatively or not at all with temperature sum. We concluded that a long-term water level drawdown in peatlands does not necessarily enhance decay of fresh organic matter. Instead, the drained site may turn into a ‘large hummock-system’ where several factors, including litter quality, relative moisture deficiency, higher acidity, lower substrate temperature, and in deeper layers also oxygen deficiency, may interact to constrain organic matter decomposition. Further, the decomposition rates may not vary systematically among sites of different soil nutrient levels following water level drawdown. Our results emphasize the importance of annual weather variations on decomposition rates, and demonstrate that single-period incubation studies incorporate an indeterminable amount of temporal variation.     

Carbon loss in drained forestry peatlands in Finland,estimated by re‐sampling peatlands surveyed in the 1980s

The total area of boreal peatlands is about 3.5 million km² and they are estimated to contain 15–30% of the global soil carbon (C) storage. In Finland, about 60 000 km², or 60% of the original peatland area, has been drained, mainly for forestry improvement. We have studied C inventory changes on forestry‐drained peatlands by re‐sampling the peat stratum in 2009 at the precise locations of quantitative peat mass analyses conducted as part of peatland transect surveys during the 1980s. The old and new profiles were correlated mainly by their ignition residue stratigraphies; at each site we determined a reference level, identifiable in both profiles, and calculated the cumulative dry mass and C inventories above it. Comparison of a total of 37 locations revealed broad variation, from slight increase to marked decrease; on average the 2009 results indicate a loss of 7.4 (SE ± 2.5) kg m^?2 dry peat mass when compared with the 1980s values. Expressed on an annual basis, the results indicate an average net loss of 150 g C m^?2 year^?1 from the soil of drained forestry peatlands in the central parts of Finland. The C balance appeared not to correlate with site fertility (fertility classes according to original vegetation type), nor with post‐drainage timber growth.     

煤炭开采对区域农田植被碳库储量的影响评价

在人类煤炭开采活动的干预下,农田生态系统中碳储量迅速变化。这种变化不仅改变了土壤肥力及农田作物产量,而且对区域及全球环境具有很大影响,事实上稳定保持其碳库是农业减缓温室气体的主要途径。该文的研究目的就是从煤炭开采对区域农田植被碳库储量影响的角度来研究煤炭开采对农田生态系统碳储量的影响,以徐州九里矿区为研究区,通过区域内农田植被碳库采样与试验、区域植被碳库储量估算模型的构建以及碳储量估算得到九里矿区煤炭开采沉陷区农田植被的碳储量和碳密度分布图,然后与情景模拟得出的该区未受到煤炭开采影响情况下,经过几十年变化后农田植被的碳储量和碳密度分布图进行对比,得出煤炭开采对沉陷区范围的农田植被碳库的扰动影响,发现与不受到煤炭开采的影响相比,在沉陷区域外围地势较高的坡地煤炭开采对农田植被碳密度的影响很小,在沉陷区地势较低的季节性积水区和常年积水湿地区煤炭开采对农田植被碳密度的影响较大。在整个煤炭开采沉陷区范围内,与不受到煤炭开采的影响相比,煤炭开采沉陷区域农田植被碳库碳储量减少2.4万t。煤炭开采对区域农田植被碳库储量的影响属于失碳效应。     

森林土壤有机碳库组分定量化研究

用一级动力学方程研究了贵州省黎平县森林土壤活性、缓效性和惰效性有机碳库的变化及分解速率,模拟结果表明:各土壤剖面的土壤活性碳库一般占总有机碳的0.5%~7.6%,平均驻留时间(M ean Residue Tim e,MRT)为41~64天;缓效性碳库占总有机碳的45%~71%,平均驻留时间为3~30年;采用酸水解法测定惰效性碳库的库容,一般占总有机碳的20%~50%。活性碳库的变化规律为混交林>阔叶林>针叶林,缓效性碳库中混交林最大,其它两种林分规律不明显;不同林龄的杉木(8年,16年,40年),非活性碳库(缓效性碳库和惰效性碳库之和)的含量变化规律为40年>16年>8年,说明40年生的杉木下土壤固碳能力比8年和16年的强;16年的又比8年的强。