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1.
以黄石市3种不同类型土壤(红壤土、潮土、水稻土)为研究对象,采用热光反射法测定土壤中黑碳、焦炭和烟炱含量,研究有机碳、黑碳、焦炭和烟炱的空间分布特征,同时分析黑碳、焦炭、烟炱与有机碳之间的相互关系及黑碳的可能来源。结果表明:黄石市表层土壤中黑碳含量的变化范围为0.01~5.79 g/kg,平均值为1.06 g/kg。其中水稻土黑碳含量最高,潮土次之,红壤最低。黑碳在有机碳中所占比例的变化范围为0.53%~89.54%,平均值为25.29%,说明黑碳对土壤有机碳库有较大的贡献。不同土壤类型黑碳/总有机碳(BC/TOC)比值存在较大的差异,红壤BC/TOC平均值最大(36.70%),其次为水稻土(25.25%),潮土最低(18.25%),这可能与土壤质地有关。黑碳、焦炭与烟炱含量和BC/TOC比值的空间变异性与区域的产业结构及工业布局有关。黑碳、焦炭与烟炱含量之间呈显著正相关,说明它们可能有共同的来源。焦炭/烟炱比值(char/soot)分析结果表明土壤中的黑碳受人为源的影响很大,主要来源于化石燃料燃烧(工业燃煤及机动车尾气排放)。  相似文献   

2.
五台山高山林线典型植被土壤有机碳特征   总被引：3，自引：1，他引：2  
刘楠  韩进斌  赵建儒  刘敏 《土壤》2019,51(5):970-978
在全球变暖背景下,土壤有机碳(SOC)已经成为全球碳循环和全球变化生态学研究热点,特别是高山林线生态交错带这一气候变化敏感区。对五台山高山林线附近亚高山草甸(CD)、华北落叶松林(HL)和云杉×华北落叶松混交林(YH)SOC含量与土壤有机碳密度(SOCD)进行探讨,结果表明:3种植被SOC含量随土壤深度增加而减少,SOCD则与之相反,且其SOC和SOCD分布均具有"表聚效应"。五台山亚高山森林(HL、YH)土壤SOC总含量和总SOCD都高于亚高山草甸(CD),与中国亚高山土壤一致,但与亚洲以外的世界各大洲不同;且五台山亚高山土壤总SOC含量和SOCD与中国亚高山土壤均值近似,大于其他各大洲均值。显著影响五台山SOC的因素(P0.05)与世界尺度亚高山土壤不同,且土壤厚度和气候因子(P0.05)对世界尺度亚高山森林SOC的影响比亚高山草甸/草原土壤(P0.05)显著。因此,五台山亚高山森林土壤固碳能力比亚高山草甸强,其亚高山土壤的SOC总含量和总SOCD在全国范围内处于平均水平,而中国亚高山土壤碳库在世界范围内占据领先地位,但仍需进一步探讨来减少多尺度研究的不确定性。  相似文献   

3.
Abstract

The issue of soil organic carbon (SOC) is of increasing concern. Because SOC, as an important soil component in farming systems, is essential for improving soil quality, sustaining food production and quality, and maintaining water quality and as a major part of the terrestrial carbon reservoir, it plays an important role in the global carbon cycle. In this paper, a total of 665 soil samples from different depths were collected randomly in the autumn of 2007, and the spatial variability of SOC content at a small catchment of the Loess Plateau was analysed using classical statistics and geo-statistical analysis. In nonsampled areas classical kriging was utilized for interpolation of SOC estimation. The classic statistical analysis revealed moderate spatial variability with all five layers of SOC-content. In addition, the average SOC content decreased with soil depth and the relationship can be modelled by an exponential equation (y=3.1795x ?1.2015, R 2=0.9866) and all of the SOC-content data in the different depth were normally distributed. The geo-statistical analysis indicated a moderate spatial dependence in 0–60 cm, while in the 60–80 cm depth spatial dependence was strong. The semi-variogram could be fitted by an exponential model for 0–10 cm depth; by a spherical model for 10–20 cm depth and 60–80 cm depth; and by a Gaussian model for 20–60 cm depth. The range increases with increasing depth. In addition, classical kriging could successfully interpolate SOC content in the catchment. In general, the geo-statistics method on a watershed scale could be accurately used to evaluate spatial variability of the SOC content in the Loess Plateau, China.  相似文献   

4.
汤松波  习丹  任文丹  旷远文 《土壤》2018,50(1):122-130
不同植被类型下土壤有机碳(SOC)储量和动态变化是全球变化研究的热点之一。对南亚热带鹤山6种不同植被类型(灌草、马尾松林、桉树林、乡土树林、马占相思林、季风常绿阔叶林)SOC干湿季、空间(0~10,10~20,20~40 cm)变化特征、土壤惰性指数及其与土壤有效氮(TAN)的关系研究表明:(1)6种植被中,干季SOC含量显著高于湿季,SOC含量随土层深度降低,马占相思林SOC含量最高,马尾松林和灌草最低;(2)6种植被SOC储量在0~10 cm土层所占比例最高,占0~40 cm土层SOC含量40%以上;(3)土壤惰性指数随土壤深度增加而下降,常绿阔叶林、乡土树林和马占相思林烷基碳和ROC惰性指数高于桉树林和马尾松林,揭示这3种植被SOC具有更高稳定性;(4)SOC与土壤TAN含量呈显著正相关。结果揭示,在植被恢复过程中,选择豆科植物,辅以乡土树种营造常绿阔叶林,有利于提高森林潜在碳汇功能。  相似文献   

5.
黄土高原小流域土壤有机碳空间变异性研究   总被引：12，自引：0，他引：12  
Soil organic carbon (SOC) has great impacts on global warming, land degradation and food security. Classic statistical and geostatistical methods were used to characterize and compare the spatial heterogeneity of SOC and related factors, such as topography, soil type and land use, in the Liudaogou watershed on the Loess Plateau of North China. SOC concentrations followed a log-normal distribution with an arithmetic and geometric means of 23.4 and 21.3 g kg-1, respectively, were moderately variable (CV = 75.9%), and demonstrated a moderate spatial dependence according to the nugget ratio (34.7%). The experimental variogram of SOC was best-fitted by a spherical model, after the spatial outliers had been detected and subsequently eliminated. Lower SOC concentrations were associated with higher elevations. Warp soils and farmland had the highest SOC concentrations, while aeolian sand soil and shrublands had the lowest SOC values. The geostatistical characteristics of SOC for the different soil and land use types were different. These patterns were closely related to the spatial structure of topography, and soil and land use types.  相似文献   

6.
松嫩平原土壤有机碳空间分异   总被引：4，自引：0，他引：4  
Soil organic carbon (SOC) and its relationship with landscape attributes are important for evaluating current regional, continental, and global carbon stores. Data of SOC in surface soils (0–20 cm) of four main soils, Cambisol, Arenosol, Phaeozem, and Chernozem, were collected at 451 locations in Nongan County under maize monoculture in the Song-Nen Plain, Northeast China. The spatial characteristics of soil organic carbon were studied, using geographic information systems (GIS) and geostatistics. Effects of other soil physical and chemical properties, elevation, slope, and soil type on SOC were explored. SOC concentrations followed a normal distribution, with an arithmetic mean of 14.91 g kg-1 . The experimental variogram of SOC was fitted with a spherical model. There were significant correlations between soil organic carbon and bulk density (r =-0.374**), pH (r = 0.549**), total nitrogen (r = 0.781**), extractable phosphorus (r =-0.109*), exchangeable potassium (r = 0.565**), and cation exchange capacity (r = 0.313**). Generally, lower SOC concentrations were significantly associated with high elevation (r =-0.429**). Soil organic carbon was significantly negatively correlated with slope gradient (r =-0.195**). Samples of the Cambisol statistically had the highest SOC concentrations, and samples of the Arenosol had the lowest SOC value.  相似文献   

7.
Soil organic carbon (SOC) and total nitrogen (TN) stocks can be affected by soil erosion and this is of great significance in relation to global environmental concern about environmental change. This study investigated the spatial patterns of 137Cs, SOC and TN as well as their relationships for an agricultural catchment and presents a budget analysis of the redistributions of SOC and TN for the period 1954–2010. 137Cs, SOC and TN inventories were found to be significantly correlated, and the application of the137Cs technique proved to be useful for evaluating SOC and TN dynamics in the Luvic Phaeozem soil typical of the Chinese black soil region. Spatial patterns of soil, SOC and TN were greatly influenced by shelterbelts/windbreaks within the study catchment. Higher 137Cs, SOC and TN stocks were generally found upwind of the shelterbelts and at the study catchment outlet, whereas lower stocks of 137Cs, SOC and TN occurred behind the shelterbelts (i.e. in the lee). The total net losses of SOC and TN over the past 56 years were approximately 152 and 11 t respectively, with 47 and 38 per cent of the eroded SOC and TN in soils redeposited within the study catchment, respectively. Based on the relationships of soil, SOC and TN in the investigated catchment, erosion‐induced SOC and TN losses per year are around 1·2 × 106 and 0·1 × 106 t for the typical black soil region of Northeast China. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

8.
Soils of the high latitudes are expected to respond sensitively to climate change, but still little is known about carbon and nitrogen variability in them. We investigated the 0.44‐km2 Little Grawijka Creek catchment of the forest tundra ecotone (northern Krasnoyarsk Krai, Russian Federation) in order (i) to relate the active‐layer thickness to controlling environmental factors, (ii) to quantify soil organic carbon (SOC) and total nitrogen (NT) stocks, and (iii) to assess their variability with respect to different landscape units. The catchment was mapped on a 50 × 50 m grid for topography, dominant tree and ground vegetation, organic‐layer and moss‐layer thickness, and active‐layer thickness. At each grid point, bulk density, and SOC and NT concentrations were determined for depth increments. At three selected plots, 2‐m deep soil cores were taken and analysed for SOC, NT and 14C. A shallow active layer was found in intact raised bogs at plateaux situations and in mineral soils of north‐northeast (NNE) aspect. Good drainage and greater solar insolation on the south‐southwest (SSW) slopes are reflected in deeper active layers or lack of permafrost. Organic carbon stocks to a soil depth of 90 cm varied between 5 and 95 kg m–2. The greatest stocks were found in the intact raised bogs and on the NNE slopes. Canonical correspondence analysis indicates the dominant role of active‐layer thickness for SOC and NT storage. The 2‐m soil cores suggest that permafrost soils store about the same amount of SOC from 90 to 200 cm as in the upper 90 cm. Most of this deep SOC pool was formed in the mid‐Holocene (organic soils) and the late Pleistocene (mineral soils). Our results showed that even within a small catchment of the forest tundra, active‐layer thickness and, hence, SOC and NT storage vary greatly within the landscape mosaic. This has to be taken into account when using upscaling methods such as remote sensing for assessing SOC and NT storage and cycling at a regional to continental level.  相似文献   

9.
Orchards have a high potential for carbon sequestration. However, little research is available on the spatial variability at catchment scale and on the difference between the tree area and the lanes. We analyzed theik spatial variability of soil organic carbon stock, SOCstock at 90 cm depth in an 8-ha catchment in Southern Spain with olives on a vertic soil. Results showed higher soil organic carbon concentration, SOC, in the tree area as compared to the lane up to 60 cm depth, but its impact on SOCstock was negligible since it was compensated by the higher soil bulk density in the lane. SOC at different depths was correlated with that in the top 0–5 cm. The overall SOCstock of the orchard was 4.14 kg m−2, ranging between 1.8 and 6.0 kg m−2. This SOCstock is in the mid-lower range of values reported for olive orchards, measured at smaller scale, and similar to those other intensive field crops and agroforestry under comparable rainfall conditions. The spatial variability in SOCstock was correlated to several geomorphological variables: elevation, cumulative upstream area, topographic wetness index, sediment transport index, and tillage erosion. Differences in SOC and SOCstock are driven by the sediment redistribution downslope, mainly by tillage erosion, and higher soil water availability in lower areas allowing higher biomass production. These topographic indexes and the correlation between SOC in the topsoil and SOCstock up to 90 cm should be further explored in other typology of olive orchards for facilitating the mapping of SOCstock.  相似文献   

10.
An accurate estimation of soil organic carbon (SOC) is important for the evaluation and management of carbon (C) flux in terrestrial ecosystems. However, there is little work on the spatial variability of SOC in deep soils and its driving factors. Thus, the objective of the study was to derive the primary factors dominating the spatial distribution of SOC in different soil layers with the use of the autoregressive state‐space approach. The concentration of SOC was measured to the depth of 500 cm (n  = 86) along a south–north transect of China's Loess Plateau. The mean SOC of the 500‐cm soil profile generally decreased from south to north following the decreasing rainfall gradient. Based on the investigated factors, the state‐space model was able to capture 90.3–99.9% of the spatial variability of SOC in the various soil layers. According to the coefficients in the optimal state‐space model for each soil layer, climatic factors such as precipitation and temperature had a dominant control over the spatial distribution of SOC at shallow depths. However, both climatic and edaphic (e.g. soil texture) factors, and to a small extent land use, influenced the spatial behavior of SOC at the 40–200 cm soil depth. For soil layers below 200 cm, the importance of land use was revealed, and the spatial characteristics of SOC were together driven by land use, climatic and edaphic factors. This is critical for the management of soil C flux in deep soils and the C stock and cycle in terrestrial ecosystems. Table SI. Basic properties of soils and climate and elevation under three land uses along the south–north transect on the Loess Plateau (mean ± standard deviation). Note that SWC is gravimetric soil water content. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

11.
水分梯度对若尔盖高寒湿地土壤活性有机碳分布的影响   总被引：4，自引：1，他引：4  
沿自然原因和人为原因形成的水分梯度,对若尔盖高寒湿地沼泽土和泥炭土的有机碳(SOC)和活性有机碳(LC)进行了研究。研究表明,若尔盖高寒湿地沼泽土有机碳和全氮沿水分梯度(减小)变化趋势一致,即在表层0—10cm湿润环境中的有机碳和全氮含量远高于淹水环境和过渡地带,而10—30 cm沿水分梯度差异变小。泥炭土的有机碳和氮素含量在湿润环境远大于淹水(流水)环境。这说明当时的挖沟排水疏干沼泽使得相当一部分土壤有机碳或者释放到大气中,或者随水流流失。沼泽土活性有机碳在表层0—10 cm沿水分梯度升高;在10—30 cm差异变小,与有机碳和氮素的变化趋势一致。泥炭土的活性有机碳沿水分梯度升高,与泥炭土有机碳和氮素变化趋势一致。这一方面反映了两种土壤类型成土过程的不同,另一方面也反映了自然原因和人为原因造成的差异。沼泽土的碳氮比沿水分梯度有降低的趋势而泥炭土的碳氮比沿水分梯度有升高的趋势。此外,高寒沼泽土碳氮比,pH值以及机械组成都是影响土壤有机碳,氮素和活性有机碳的重要因子。  相似文献   

12.
南方侵蚀治理区土壤碳分布及主控因素研究   总被引：2，自引：0，他引：2  
研究侵蚀治理区土壤碳区域分布影响因素对揭示退化土壤有机碳恢复有重要的意义。本文以江西省兴国县侵蚀治理恢复区林地土壤有机碳为研究对象,评价了土壤类型和成土母质对土壤有机碳的影响及其主控作用。结果表明：兴国县侵蚀治理恢复区林地土壤有机碳受土壤类型和成土母质影响显著,其中黄红壤各土层土壤有机碳含量均显著高于红壤;千枚岩发育的土壤有机碳显著高于红砂岩和花岗岩。对比土壤类型和成土母质对土壤有机碳的影响作用大小发现,在表层0 ~ 20 cm土壤类型对土壤有机碳变异解释能力大于30%,成土母质的解释能力约为17%,土壤类型是影响表层土壤有机碳的主控因素;表下层20 ~ 30 cm 土壤有机碳变异的解释能力则表现为成土母质(28.8%)与土壤类型(27.5%)基本相当,同为主控因素。因此,兴国县侵蚀治理恢复区土壤类型和成土母质对土壤有机碳的影响作用不容忽视,合理地分区展开水土保持工作有利于退化土壤的碳恢复。  相似文献   

13.
Black carbon (BC) or charcoal is thought to represent an important component of the carbon cycle, but has seldom been quantified in soils. We quantified soil BC in a temperate mixed-grass savanna in the southern Great Plains using benzenecarboxylic acids as molecular markers for BC. Soils were collected from four fire treatments (repeated summer fires in 1992 and 1994; repeated winter fires in 1991, 1993 and 1995; alternate-season fires in winter 1991, summer 1992, and winter 1994; and unburned control) at 0-10 and 10-20 cm depth in 1996. Black carbon concentrations ranged from 50 to 130 g BC kg−1 of soil organic carbon (SOC), or from 0.55 to 1.07 g BC kg−1 of whole soil in this mixed grass savanna. The BC contribution to SOC increased significantly with soil depth (P<0.05). Repeated fires increased BC slightly compared to the unburned controls; however, the effects of repeated fires on BC were not statistically significant in this mixed-grass savanna. Results of this study provide estimates of BC concentrations for native, uncultivated mixed-grass savanna, and indicate that 2-3 fires have little effect on the size of the soil BC pool in this region.  相似文献   

14.
冲积平原区土壤碳密度估算及其空间分布   总被引：2，自引：1，他引：1  
冲积平原区通常具有复杂的剖面质地层次排列,为了准确估算冲积平原区土壤碳密度的空间分布特征,该文在华北冲积平原区的河北曲周县选取了121个土壤剖面,测定了各土层有机碳含量,构建了基于负指数函数的土壤有机碳垂向分布模型,结合地统计学方法绘制了该县土壤碳密度的空间分布图。结果表明,土壤有机碳含量随深度增加呈逐渐递减的趋势,各土层有机碳含量均属于中等变异程度。0~20和20~40 cm土壤有机碳空间连续性较好,它们的空间相关距离分别为14和3 km,而下层(40 cm)土壤有机碳均表现为纯块金效应结构。土壤有机碳垂向分布模型可以很好地描述剖面土壤有机碳含量的变化特征,且预测与实测的土壤有机碳含量的均方根误差仅为0.70 kg/m3,决定系数达到了0.95。曲周县土壤有机碳密度的空间分布总体表现为西北高东南低的趋势。其空间分布主要受土壤类型和质地的影响,其中潮土和盐化潮土的碳密度明显高于褐土化潮土,质地较细的土壤(轻壤、中壤和粘土)碳密度明显高于质地较粗的土壤(砂土和砂壤)。该研究为冲积平原区土壤碳密度的估算提供了一种新的方法。  相似文献   

15.
土壤矿物吸附和土壤团聚体对土壤有机碳含量的影响研究   总被引：3，自引：1，他引：2  
Soil organic carbon (SOC) can act as a sink or source of atmospheric carbon dioxide; therefore, it is important to understand the amount and composition of SOC in terrestrial ecosystems, the spatial variation in SOC, and the underlying mechanisms that stabilize SOC. In this study, density fractionation and acid hydrolysis were used to assess the spatial variation in SOC, the heavy fraction of organic carbon (HFOC), and the resistant organic carbon (ROC) in soils of the southern Hulunbeier region, northeastern China, and to identify the major factors that contribute to this variation. The results showed that as the contents of clay and silt particles (0--50 μm) increased, both methylene blue (MB) adsorption by soil minerals and microaggregate contents increased in the 0--20 and 20--40 cm soil layers (P < 0.05). Although varying with vegetation types, SOC, HFOC, and ROC contents increased significantly with the content of clay and silt particles, MB adsorption by soil minerals, and microaggregate content (P < 0.05), suggesting that soil texture, the MB adsorption by soil minerals and microaggregate abundance might be important factors influencing the spatial heterogeneity of carbon contents in soils of the southern Hulunbeier region.  相似文献   

16.
东北黑土有机碳的分布及其损失量研究   总被引：11，自引：0，他引：11  
为了分析东北黑土土壤有机碳(SOC)的分布特征及其开垦以来黑土SOC的损失程度,我们于2004～2005年在黑龙江和吉林两省采集了32个自然黑土剖面样品,在每个自然黑土样品附近对应采集32个景观条件相似的耕作黑土样品。结果表明,自然黑土样品0～30cm土层SOC含量平均为32.20 g kg-1,最高可达63.46 g kg-1,黑龙江省自然黑土SOC含量(34.55 g kg-1)高于吉林省(23.80 g kg-1)。耕作土壤SOC平均含量为22.71 g kg-1,远低于自然土壤。受温度的影响,随着纬度的增加,自然黑土与耕作黑土SOC含量逐渐递增。由于土壤侵蚀以及耕垦和去除作物残留物等农业管理措施的综合作用,使得耕作黑土表层SOC含量小于自然黑土。与自然黑土相比,耕作黑土0～10cm土层SOC损失量在26.84%～46.57%之间,亚表层损失相对较少。黑土SOC含量下降也是土壤水土流失致使黑土层变薄的一个直接表现。耕作黑土表层流失厚度可以通过自然与耕作黑土剖面SOC含量的分异差值来估算。通过对土壤剖面上SOC的分布进行校正剔除土壤侵蚀的影响后得到的同等深度SOC含量的差值才可视为由耕作以及有机质输入量差异等因素造成的SOC损失量。未经校正而进行的自然黑土和耕作黑土同一深度SOC含量的比较可能过高估计了农业管理措施对土壤SOC损失量的影响。  相似文献   

17.
南方红壤丘陵区土壤侵蚀-沉积作用对土壤酶活性的影响   总被引：6，自引：0，他引：6  
土壤酶与土壤矿质营养元素循环、能量转移等密切相关。明确土壤酶对土壤侵蚀—沉积作用的响应机制,有助于进一步把握土壤侵蚀在全球碳循环中的作用。通过分析湘中红壤丘陵区松林坡面侵蚀区及沉积区土壤酶活性的变化特征,揭示了酶活性与土壤主要养分因子之间的关系,并在此基础上深入探讨了土壤侵蚀—沉积作用对土壤酶活性的影响。结果表明:沉积区绝大多数土层土壤有机碳(soil organic carbon,SOC)、全氮(total nitrogen,TN)、可溶性有机碳(dissolved organic carbon,DOC)、脲酶、酸性磷酸酶及过氧化氢酶活性均要显著高于侵蚀区。土壤沉积作用明显提高了土壤养分含量及酶活性。其次,侵蚀区与沉积区土壤养分含量及酶活性差异在侵蚀干扰较为严重的表层(0~30 cm)土壤表现较为明显,随着土壤深度的增加差异逐渐减小。侵蚀区与沉积区SOC、TN、DOC及酶活性均随土壤深度的增加呈现总体下降的趋势。相关性分析表明,土壤脲酶、酸性磷酸酶、过氧化氢酶之间及其与SOC、TN、DOC之间均存在极显著正相关关系(p0.01)。此外,偏冗余分析结果进一步表明SOC是解释土壤酶活性动态变化的主要因子,其解释量达7.5%,侵蚀诱导SOC在坡面的再分布是影响土壤酶活性的重要途径之一。  相似文献   

18.
四川省仁寿县土壤有机碳空间分布特征及其主控因素   总被引：6，自引：0，他引：6  
准确地获取区域尺度内土壤有机碳含量信息对土壤碳调控及全球环境变化具有重要意义。本研究基于野外实地采集的555个表层(0~20 cm)土样,探讨四川省仁寿县土壤有机碳空间分布特征及其主控因素。运用方差分析和回归分析对比了成土母质、土壤类型和土地利用方式对仁寿县土壤有机碳空间分布的影响。结果表明:研究区表层土壤有机碳含量为3.36~37.10 g·kg-1,平均13.46 g·kg-1,变异系数为48.87%,属中等强度的空间变异性。块金效应C0/(C0+C)为66.7%,空间分布受结构性因素和随机性因素的共同影响,总体呈现北高南低的趋势。土地利用方式和土壤类型对土壤有机碳的影响极显著(P0.01),而成土母质的影响不明显(P=0.256)。土类能够独立解释23.7%的土壤有机碳空间变异;亚类和土类的解释能力接近,分别为27.0%和27.1%,土壤亚类可作为探讨该区域土壤有机碳空间变化的最小土壤分级单元。土地利用方式能独立解释53.0%的土壤有机碳空间变异,远大于土壤类型,是研究区土壤有机碳空间分布的主控因素。  相似文献   

19.
石羊河流域干旱荒漠区人工梭梭林对土壤碳库的影响   总被引：3，自引：0，他引：3  
采用野外调查与室内分析相结合的方法,研究石羊河流域民勤干旱沙区种植人工梭梭林4,13,36年后的土壤有机碳(Soil organic carbon,SOC)、无机碳(Soil inorganic carbon,SIC)、全氮(Total nitrogen,TN)和总碳(soil total carbon,TC)含量及储量变化特征。结果表明:流动沙地种植梭梭后,0-50cm层灌丛下和行间SOC和TN含量总体随造林年限增加而增加,5-50cm层灌丛下SIC含量在13年梭梭林地最高。36,13年林地0-50cm层灌丛下SOC和TN储量均高于行间,而13年灌丛下SIC储量低于行间,4年灌丛下5-50cm层SOC、TN和SIC储量均低于行间。0-50cm层土壤有机碳、无机碳、全氮储量增幅分别为102.44%,24.66%,54.55%,36年林地SOC和TN储量随土层加深先降低后增加,但4,13年和流动沙地SOC、SIC和TN储量均随土层加深而增加。土壤有机碳占总碳比例随造林年限增加而增加。相关分析结果表明,土壤颗粒组成、造林年限、土层深度等与土壤有机碳和全氮储量显著相关(P0.01)。民勤干旱沙区造林提高了土壤碳库截存量,并且随林龄增长而增长。  相似文献   

20.
江苏省土壤有机碳空间差异性以及影响因素研究   总被引：2，自引：0，他引：2  
Soil organic carbon (SOC) plays a key role in the global carbon cycle.In this study,we used statistical and geostatistical methods to characterize and compare the spatial heterogeneity of SOC in soils of Jiangsu Province,China,and investigate the factors that influence it,such as topography,soil type,and land use.Our study was based on 24 186 soil samples obtained from the surface soil layer (0-0.2 m) and covering the entire area of the province.Interpolated values of SOC density in the surface layer,obtained by kriging based on a spherical model,ranged between 3.25 and 32.43 kg m 3.The highest SOC densities tended to occur in the Taihu Plain,Lixia River Plain,along the Yangtze River,and in high-elevation hilly areas such as those in northern and southwest Jiangsu,while the lowest values were found in the coastal plain.Elevation,slope,soil type,and land use type significantly affected SOC densities.Steeper slope tended to result in SOC decline.Correlation between elevation and SOC densities was positive in the hill areas but negative in the low plain areas,probably due to the effect of different land cover types,temperature,and soil fertility.High SOC densities were usually found in limestone and paddy soils and low densities in coastal saline soils and alluvial soils,indicating that high clay and silt contents in the soils could lead to an increase,and high sand content to a decrease in the accumulation of SOC.SOC densities were sensitive to land use and usually increased in towns,woodland,paddy land,and shallow water areas,which were strongly affected by industrial and human activities,covered with highly productive vegetation,or subject to long-term use of organic fertilizers or flooding conditions.  相似文献   

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