长江三角洲地区土壤无机碳库研究

土壤碳库变化对于全球温室效应、全球碳循环有重大的影响。研究基于最新完成的1〖DK〗∶250 000多目标地球化学调查及相关研究成果,运用地理信息系统软件ARCGIS 92、统计分析软件SPSS130,对长江三角洲地区0~20、0~100、0~180 cm深度土壤无机碳密度及储量做出实测统计。长江三角洲地区0~20、0~100、0~180 cm深度土壤无机碳库储量分别为5099、35647、67726Tg,无机碳密度分别为070、490、930 kg/m2。研究区主要分布土壤为水稻土、潮土,水稻土0~20、0~100、0~180 cm深度土壤无机碳密度分别为057、385、886 kg/m2;潮土无机碳密度分别为117、854 、1537 kg/m2。研究提供最新的土壤无机碳库实测统计信息,弥补中国区域土壤无机碳库清单的空白,完善了中国区域土壤碳库清单,为研究中国区域土壤碳固定潜力、深入全面理解区域碳循环提供了基准数据.     

川中丘陵紫色土区农田土壤有机碳储量及空间分布特征

土壤有机碳在陆地生态系统碳循环中起着举足轻重的作用。针对农田区域内典型县域尺度有机碳储量及其空间格局特征的研究,可以为区域农田土壤固碳提供参考,为研究我国土壤有机碳储量提供基础数据支持。基于2012年农田土壤有机碳分析调查数据,结合GIS和GPS技术对川中丘陵区盐亭县土壤有机碳密度和储量及空间格局进行了估算和分析。结果表明:其主要土壤类型的0~20 cm耕层土壤有机碳密度为111~426 kg/m2,平均值为266 kg/m2,水田和旱地耕层土壤有机碳密度分别为345和234 kg/m2,均低于全国平均值;全县20 cm深度土壤有机碳总储量250×109 kg C,紫色土类土壤有机碳储量最大,为153×109kg C,水稻土次之,有机碳储量0.93×109kg C,两者占据了农田土壤有机碳储量约98%,冲积土和黄壤土类由于面积小,有机碳储量也最低。各土壤类型有机碳储量丰度指数(RI)值都较低,碳存储能力处于中下水平。在县域农田尺度,有机碳空间格局与气候差异、植被类型关系不大,土壤类型空间差异和地形差异是有机碳空间格局形成的主要原因。     

Organic carbon fluxes in the system soil-phytocenosis of bilberry-sphagnum spruce forest in the middle taiga zone of the Komi republic

Quantitative characteristics of organic carbon stock and distribution in the main ecosystem blocks and production-destruction processes in the soil-phytocenosis system have been evaluated in wet oldgrowth bilberry-sphagnum forest. It has been shown that equivalent amounts of carbon are accumulated in the soil and plant reservoirs of the ecosystem and that atmospheric carbon fixation for phytomass production prevails over carbon release in the course of necromass decomposition.     

长江三角洲地区土壤有机碳库研究

土壤碳库变化对于全球温室效应、全球碳循环有重大的影响。基于新近完成的1：250 000多目标地球化学调查及相关研究成果,运用地理信息系统软件ARCGIS 9.2、统计软件SPSS13.0,对长江三角洲地区0~20、0~100、0~180 cm深度土壤有机碳密度及储量作出实测统计。结果表明:长江三角洲地区0~20 cm土壤有机碳库储量为238.65 Tg,有机碳密度为3.28±0.92 kg/m2,各类型土壤有机碳密度均值介于2.63~3.57 kg/m2;0~100 cm土壤有机碳库储量为822.76 Tg,有机碳密度为11.30±3.48 kg/m2,各类型土壤有机碳密度均值介于9.35~11.94 kg/m2;0~180 cm土壤有机碳库储量为1 245.72 Tg,有机碳密度为17.11±7.04 kg/m2,各类型土壤有机碳密度均值介于14.27~18.00 kg/m2。与第二次土壤普查比较,全区0~20、0~100cm土壤有机碳密度均值都表现为上升趋势,有机碳库储量增加,土壤表现为碳汇功能。提供了新的土壤碳库实测统计信息,为研究中国区域土壤碳固定潜力、深入全面理解区域碳循环提供基准数据。     

Impact of woody encroachment on soil organic carbon and nitrogen in abandoned agricultural lands along a rainfall gradient in Italy

Land use changes represent one of the most important components of global environmental change and have a strong influence on carbon cycling. As a consequence of changes in economy during the last century, areas of marginal agriculture have been abandoned leading to secondary successions. The encroachment of woody plants into grasslands, pastures and croplands is generally thought to increase the carbon stored in these ecosystems even though there are evidences for a decrease in soil carbon stocks after land use change. In this paper, we investigate the effects of woody plant invasion on soil carbon and nitrogen stocks along a precipitation gradient (200?C2,500?mm) using original data from paired experiment in Italian Alps and Sicily and data from literature (Guo and Gifford Glob Change Biol 8(4):345?C360, 2002). We found a clear negative relationship (?0.05%?C?mm^?1) between changes in soil organic carbon and precipitation explaining 70% of the variation in soil C stocks after recolonization: dry sites gain carbon (up to +67%) while wet sites lose carbon (up to ?45%). In our data set, there seem to be two threshold values for soil carbon accumulation: the first one is 900?mm of mean annual rainfall, which separates the negative from the positive ratio values; the second one is 750?mm, which divides the positive values in two groups of sites. Most interestingly, this threshold of 750?mm corresponds exactly to a bioclimatic threshold: sites with <750?mm mean annual rainfall is classified as thermo-mediterranean sites, while the ones >750?mm are classified as mesomediterranean sites. This suggests that apart from rainfall also temperature values have an important influence on soil carbon accumulation after abandonment. Moreover, our results confirmed that the correlation between rainfall and trend in soil organic carbon may be related to nitrogen dynamics: carbon losses may occur only if there is a substantial decrease in soil nitrogen stock which occurs in wetter sites probably because of the higher leaching.     

Productivity of mosses and organic matter accumulation in the litter of sphagnum larch forest in the permafrost zone

Productivity of the moss cover and necromass accumulation in the litter of a sphagnum larch forest have been estimated on the basis of tree age. It has been shown that the total carbon stock in the litter of a 100-year-old stand, including organic matter not destroyed by fire, exceeds the corresponding value for the tree stand itself by more than an order of magnitude. The accumulation of organic matter on the soil surface inhibits the growth of larch. In particular, this factor impairs hydrothermal conditions in the soil and causes a rise of the permafrost table; as a consequence, lower layers of the root system die off.     

Soil carbon stocks after conversion of Amazonian tropical forest to grazed pasture: importance of deep soil layers

Recent studies suggest that carbon (C) is stored in the topsoil of pastures established after deforestation. However, little is known about the long-term capacity of tropical pastures to sequester C in different soil layers after deforestation. Deep soil layers are generally not taken into consideration or are underestimated when C storage is calculated. Here we show that in French Guiana, the C stored in the deep soil layers contributes significantly to C stocks down to a depth of 100 cm and that C is sequestered in recalcitrant soil organic matter in the soil below a depth of 20 cm. The contribution of the 50–100 cm soil layer increased from 22 to 31 % with the age of the pasture. We show that long-term C sequestration in C4 tropical pastures is linked to the development of C3 species (legumes and shrubs), which increase both inputs of N into the ecosystem and the C:N ratio of soil organic matter. The deep soil under old pastures contained more C3 carbon than the native forest. If C sequestration in the deep soil is taken into account, our results suggest that the soil C stock in pastures in Amazonia would be higher with sustainable pasture management, in particular by promoting the development of legumes already in place and by introducing new species.     

IPCC框架下木质林产品碳储核算研究进展:方法选择及关联利益

木质林产品的碳储功能可有效降低大气中二氧化碳的浓度,其碳储量核算已被纳入气候变化缔约国温室气体清单报告,各国基于CBDR原则对木质林产品的碳储计量及贸易流动核算方法学在国家层面的争议及协调,关系到未来在气候变化谈判中的减排责任分配及利益分享。本文首先概括了IPCC历次会议关联木质林产品碳储核算议题及谈判进程,纵向梳理了碳储计量问题的研究进展。其次,对比不同国家和地区关于核算方法的应用及争议,总结不同核算方法在各国间的适用情况及其关联利益。最后,从清单报告和国际贸易角度分析了生产法与储量变化法对林产品碳储计量的不同影响,归纳了不同角度下两种核算方法的适用属性。研究表明:1缔约国附件Ⅰ国家在第二协议期内报告本国木质林产品的碳储量及其变化,在假设本国木质林产品碳储贡献不为零时采用生产法核算碳储量,核算源于本国采伐木的产品碳收支已成为当前缔约国履行气候责任的基本要求;2从清单报告的角度,缔约国基于森林管理参考水平报告碳储量,生产法区别森林管理活动并核算源于可持续森林经营管理的木质林产品碳储量,符合报告的要求;3从国际贸易角度,对于中国等涉及林产品国际贸易的净进口国,储量变化法因考虑到进出口的碳计量,以储量变化法核算碳储量对中国等林产品贸易大国更具优势。     

Modeling soil organic matter dynamics as affected by soil water erosion

Soil organic carbon (SOC) stock is an important component of the global carbon (C) cycle, which has the potential to influence global climate. In this paper we presented an overview of soil organic matter (SOM) models in the context of soil erosion and discussed basic processes driving erosion-induced SOC loss. Although the mechanism of this loss is poorly understood, erosion influences SOC in two ways: redistribution of C within the watershed or ecosystem, and loss of C to the atmosphere. Erosion disperses soil, altering its microbiological activity as well as water, air and nutrient regimes. This, along with sediment enrichment, has an impact on greenhouse gas emission from soil. For most of agricultural settings, field studies suggest that cultivation along with soil erosion are the primary reasons for SOC loss. Tracing the fate of eroded C is a challenging task. Modeling is the approach taken most often. In this paper we discuss approaches used in various SOC models to assess erosion-induced C loss from soil in agricultural ecosystems. An example with Century model applied to meadow and corn-soybean rotation under chisel-till demonstrated the model's ability to respond well to different erosion scenarios. It was estimated that at soil loss rate of 10 t ha(-1) year(-1) (value often considered a threshold for maintaining productivity) 19% of the total SOC loss would be attributed to erosion after 90 years of cultivation.     

Carbon stock variation of Pinus roxburghii Sarg. Forest along altitudes of Garhwal Himalaya, India

The present study was undertaken in Pinus roxburghii forest along three different altitudes i.e., 1100, 1300 and 1500 meter above mean sea level of Garhwal Himalaya to understand the effect of altitudes on carbon stocks (live trees and soil) in Pinus roxburghii forest. Tree density of this forest ranged between 590 tree ha^?1 (upper altitude) to 640 tree ha^?1 (lower altitude). The highest total carbon density (TCD) of above and belowground carbon was 66.33 ± 29.92 Mg ha^?1 at lower altitude followed by 57.64 ± 16.75 Mg ha^?1 in middle altitude and 52.92 ± 6.52 Mg ha^?1 in upper altitude. Soil organic carbon was highest (33.20 ± 2.77 Mg ha^?1) at lower altitude followed by middle (22.61 ± 7.17 Mg ha^?1) and upper altitude (12.65 ± 6.10 Mg ha^?1). Total carbon stock (trees + soil) of Pinus roxburghii forest was maximum (99.53 Mg ha^?1) at lower altitude and minimum (65.57 Mg ha^?1) at upper altitude.     

江西省不同地貌单元耕地土壤有机碳空间变异的尺度效应

运用地统计学、地理信息系统、方差分析和回归分析相结合的方法,研究江西省不同地貌单元耕地土壤有机碳空间变异的尺度效应,尺度分为省域尺度、完整地貌单元尺度和完整地貌单元相对应的县域尺度。结果表明：(1)不同尺度下耕地土壤有机碳均值差异显著,变异系数基本不变;(2)从县域尺度到地貌单元尺度再到省域尺度,块金效应值和空间自相关距离呈增大趋势;(3)不同尺度土壤有机碳空间分布级别和面积比例差异明显,小尺度插值图信息更丰富;(4)方差分析和回归分析结果表明秸秆还田、成土母质、土壤类型、高程和土壤侵蚀对土壤有机碳空间变异存在显著影响,但不同尺度下影响程度有所差异。秸秆还田和土壤类型对土壤有机碳空间变异的影响不存在尺度效应,成土母质、高程和土壤侵蚀对其影响存在尺度效应。结果可为详细地理解不同尺度下土壤有机碳空间变异及估测土壤有机碳密度提供一定的参考依据。     

农田固碳措施对温室气体减排影响的研究进展

农田是CO2,CH4和N2O三种温室气体的重要排放源,在全球范围内农业生产活动贡献了约14%的人为温室气体排放量,以及58%的人为非CO2排放,不合理的农田管理措施强化了农田温室气体排放源特征,弱化了农田固碳作用。土壤碳库作为地球生态系统中最活跃的碳库之一,同时也是温室气体的重要源/汇。研究表明通过采取合理的农田管理措施,既可起到增加土壤碳库、减少温室气体排放的目的,又能提高土壤质量。农田土壤碳库除受温度、降水和植被类型的影响外,还在很大程度上受施肥量、肥料类型、秸秆还田量、耕作措施和灌溉等农田管理措施的影响。本文通过总结保护性耕作/免耕,秸秆还田,氮肥管理,水分管理,农学及土地利用变化等农田管理措施,探寻增强农田土壤固碳作用,减少农田温室气体排放的合理途径。农田碳库的稳定/增加,对于保证全球粮食安全与缓解气候变化趋势具有双重的积极意义。在我国许多有关土壤固碳与温室气体排放的研究尚不系统或仅限于短期研究,这也为正确评价各种固碳措施对温室气体排放的影响增加了不确定性。     

宝天曼自然保护区土壤有机碳异质性及其影响因素

自然界中,土壤碳库对于维持生态系统碳平衡起决定性作用,而土壤有机碳又是碳库中不可或缺的一员,研究土壤有机碳对于全球生态系统碳平衡具有十分重大的意义。因此,基于宝天曼土壤有机碳实测数据并运用半方差函数、克里格插值分析山地土壤有机碳垂直性特征及空间分异程度,利用地理探测器对影响土壤有机碳分布的环境因子进行相关分析,结果表明:(1)宝天曼土壤有机碳介于0.31～7.7 g/kg,属于较低水平,最高值(7.70 g/kg)出现在北坡987 m处;(2)不同土层深度的半方差函数模型不同,0～20和40～60 cm对高斯模型拟合效果更明显、20～40 cm对球状模型拟合效果较好,而线性模型对于60～80和80～100 cm土层深度拟合效果较佳,克里格插值表明0～20和20～40 cm空间分异特征相似,呈西南向东北增加的趋势,而40～60 cm土壤有机碳空间分异呈现东北高、西南低;(3)宝天曼不同土层深度受单个环境因子影响程度不同,解释力介于0.127～0.407,其中NDVI对0～20 cm土壤有机碳解释力最显著(0.407)、高程对40～60 cm土壤有机碳解释力最高(0.373),交互探测结果表明NDVI与坡度解释力最高、高程与其他因子交互探测后解释力显著增大,表明宝天曼土壤有机碳受多种环境因子共同影响,而非单一因素起决定性作用。     

Long-term dynamics of terrestrial carbon stocks in Austria: a comprehensive assessment of the time period from 1830 to 2000

This article presents a comprehensive data set on Austria’s terrestrial carbon stocks from the beginnings of industrialization in the year 1830 to the present. It is based on extensive historical and recent land use and forestry data derived from primary sources (cadastral surveys) for the early nineteenth century, official statistics available for later parts of the nineteenth century as well as the twentieth century, and forest inventory data covering the second half of the twentieth century. Total carbon stocks—i.e. aboveground and belowground standing crop and soil organic carbon—are calculated for the entire period and compared to those of potential vegetation. Results suggest that carbon stocks were roughly constant from 1830 to 1880 and have grown considerably from 1880 to 2000, implying that Austria’s vegetation has acted as a carbon sink since the late nineteenth century. Carbon stocks increased by 20% from approximately 1.0 GtC in 1830 and 1880 to approximately 1.2 GtC in the year 2000, a value still much lower than the amount of carbon terrestrial ecosystems are expected to contain in the absence of land use: According to calculations presented in this article, potential vegetation would contain some 2.0 GtC or 162% of the present terrestrial carbon stock, suggesting that the recent carbon sink results from a recovery of biota from intensive use in the past. These findings are in line with the forest transition hypothesis which claims that forest areas are growing in industrialized countries. Growth in forest area and rising carbon stocks per unit area of forests both contribute to the carbon sink. We discuss the hypothesis that the carbon sink is mainly caused by the shift from area-dependent energy sources (biomass) in agrarian societies to the largely area-independent energy system of industrial societies based above all on fossil fuels.     

丰乐河流域表层土壤有机碳空间变异特征研究

土壤有机碳含量空间变异特征的研究对于区域土壤资源的可持续利用具有重要意义。在ArcGIS技术的支持下对丰乐河流域表层土壤(0~20 cm)有机碳（SOC）含量的空间变异特征进行了研究。结果表明：丰乐河流域SOC含量为1431±4.50 g·kg-1,不同土地利用类型下SOC含量差异显著（p<001）。其中,林地SOC含量的均值最大,为1558±593 g·kg-1;水田和旱地次之（分别为1539±309 g·kg-1、1146±304 g·kg-1）;园地最小(1109±348 g·kg-1)。流域SOC含量变异系数（CV）为3144%,属中等变异程度。其中,林地的CV为3806%,在4种土地利用类型中为最大;园地、旱地的CV分别为3138%、2652%;水田的CV最小,为2007%,表明人类活动影响表层土壤有机碳含量的变异程度。研究区表层SOC半方差模型为球状模型,块金效应小于25%,存在强烈的空间自相关性,且空间变异主要由结构性因素引起。SOC含量空间分布的各向异性显著,在南北方向上变异程度最为剧烈。SOC含量空间分布表现为东北部、西南部较高,西北部偏低,总体呈斑块状分布     

Carbon accumulation in lowland bog soils of fallow lands in Murmansk oblast

The dynamics of organic carbon accumulation in lowland bog soils of Murmansk oblast were assessed by analyzing soil samples from fields formerly sown with perennial grasses but withdrawn from agricultural use three, six, and eight years ago. Within three years, the organic carbon content in the topsoil (0–20 cm) increased by 0.07%, compared to that in cultivated soil. In six-and eight-year-old fallows, the increase in the soil carbon content averaged 0.2 and 0.46%, respectively. Experimental data were used for verifying calculations of carbon turnover in lowland bog soils of fallows in Murmansk oblast by the RothC model.     

苏南水稻土有机碳矿化特征及其与活性有机碳组分的关系

通过对江苏省常熟市全市范围代表性水稻土采样并布置室内短期（20 d）培育实验，研究土壤有机碳矿化过程动态，并分析其与微生物生物量碳和水溶性有机碳含量的关系。结果表明：研究区域水稻土有机碳含量变化为488～2731 g/kg，平均为1807 g/kg，全氮含量变化为058～284 g/kg，平均为186 g/kg；微生物生物量碳、氮及水溶性有机碳含量分别为2940～1 2874，1854～8178和701～2879 mg/kg，且不同土属间存在显著差异（〖WTBX〗p〖WTBZ〗＜005）；土壤呼吸强度为3476～19168 mgCO2/（kg·d），平均为7993 mgCO2/（kg·d），不同土属间高低顺序为乌栅土＞乌黄泥土＞灰黄泥土＞白土＞黄泥土＞乌沙土；培养期内有机碳日均矿化量为1076～6520 mgCO2/kg，平均为4046 mgCO2/kg，有机碳累计矿化量为21525～1 30213 mgCO2/kg，平均为80720 mgCO2/kg，不同土属间有机碳日均矿化量和累计矿化量变化趋势为乌栅土＞乌黄泥土＞乌沙土＞白土＞灰黄泥土＞黄泥土；研究区域水稻土有机碳矿化率为307%～758%，但不同土属间差异不显著（p＞005）。统计结果表明，土壤有机碳呼吸强度和日均矿化量与微生物生物量碳及水溶性有机碳之间均呈显著正线性关系，相关系数分别为0686、0594、0826、0749。〖     

Radiocarbon and stable carbon isotope compositions of chemically fractionated soil organic matter in a temperate-zone forest

To better understand the role of soil organic matter in terrestrial carbon cycle, carbon isotope compositions in soil samples from a temperate-zone forest were measured for bulk, acid-insoluble and base-insoluble organic matter fractions separated by a chemical fractionation method. The measurements also made it possible to estimate indirectly radiocarbon ((14)C) abundances of acid- and base-soluble organic matter fractions, through a mass balance of carbon among the fractions. The depth profiles of (14)C abundances showed that (1) bomb-derived (14)C has penetrated the first 16cm mineral soil at least; (2) Delta(14)C values of acid-soluble organic matter fraction are considerably higher than those of other fractions; and (3) a significant amount of the bomb-derived (14)C has been preserved as the base-soluble organic matter around litter-mineral soil boundary. In contrast, no or little bomb-derived (14)C was observed for the base-insoluble fraction in all sampling depths, indicating that this recalcitrant fraction, accounting for approximately 15% of total carbon in this temperate-zone forest soil, plays a role as a long-term sink in the carbon cycle. These results suggest that bulk soil organic matter cannot provide a representative indicator as a source or a sink of carbon in soil, particularly on annual to decadal timescales.     

向家坝水电站不同修复模式下根际土壤微生物化学计量特征

为探究水电站扰动区人工植被恢复后土壤质量及肥力的变化,以向家坝植被混凝土、厚层基材和框格梁3种典型边坡下优势物种荩草根际与非根际土壤为研究对象,对土壤的养分和微生物生态化学计量比进行研究。结果表明：（1）植被混凝土、厚层基材样地的养分平均含量均显著高于框格梁样地;植被混凝土、框格梁样地下土壤养分含量在根际存在一定的富集,以有机碳的富集作用最为明显,而厚层基材样地则表现为土壤全量养分在根际土壤中存在亏缺;（2）植被混凝土和框格梁修复模式样地的土壤微生物量为根际土壤较高,MBC/MBN、MBC/MBP表现为非根际土壤较高,3种样地下根际与非根际土壤微生物生态化学计量比差异性显著（P＜0.05）;（3）相关性分析表明,土壤微生物碳、微生物氮、有机碳和全氮之间具有显著的正相关性（P＜0.01）,微生物量磷与土壤有机碳和全磷具有极显著的正相关性（P＜0.01）。综合评价十数年后向家坝水电站工程扰动区人工修复土壤技术,植被混凝土和厚层基材修复措施对该区土壤全量养分含量的累积作用较好,框格梁样地的植物生长发育受到磷素营养的限制较大。     

上海土壤有机碳储量及其空间分布特征

区域土壤碳库的估算不仅是陆地土壤碳循环研究的重要内容,同时也可为国家尺度的土壤碳库的估算提供更多的数据支持。利用上海第二次土壤普查资料,结合GIS技术对上海土壤有机碳储量、碳密度及其空间分布格局展开研究,结果表明,上海地区0～100 cm深度的土壤有机碳总储量为576×107 t,占全国的0.062 6%,0～100 cm的平均土壤有机碳密度为1055 kg/m2,高于全国平均值,反映出上海土壤具有较高的碳蓄积能力。各类土壤中,水稻土的土壤碳储量最大,其次是灰潮土和滨海盐土,而黄棕壤由于面积狭小,所以土壤碳储量最小。各类土壤0～100 cm土壤有机碳密度的大小顺序依次为水稻土>灰潮土>黄棕壤>滨海盐土。从空间分布格局来看,上海土壤碳密度呈现为西高东低,在局部范围内还表现出高低相间,错综复杂的局面,这种分布规律在一定程度上体现了地形、微地貌、母质、土地利用方式等因素的影响。而快速的城市化引起的土地利用变化造成了土壤碳库的净碳损失量为39244万t,相当于2000年化石燃料产生的碳排放的9.86%,这表明在经济和城市快速发展地区,土地利用变化已经成为影响土壤碳库的重要驱动力。