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1.
This study was carried out in the Gurbantünggüt Desert,Uygur Autonomous Region of Xinjiang,Northwest China in August,2009.To quantify the storage,contribution and vertical distribution patterns of plant biomass carbon (PBC)and soil organic carbon(SOC)in the study area,we investigated the carbon concentrations and its vertical distribution in three different desert shrubland communities dominated by Reaumuria soongorica,Haloxylon ammodendron+R.soongorica and Tamarix ramosissima+R.soongorica,respectively.We analyzed vertical distribution of root biomass carbon and soil carbon contents by excavating soil profiles for each dominated community.The results show that SOC is considerably the larger carbon pool in the soil layers of 1.0-3.0 m(the mean value of three shrubland communities is 38.46%)and 3.0-5.0 m(the mean value is 40.24%).In contrast,70.74%of belowground biomass carbon storage in 0-1.0 m layer,and its content decrease with increasing soil depth.The Haloxylon ammodendron+R. soongorica shrubland community has the highest belowground biomass carbon among three selected communities. This study highlights the importance of SOC stored in deep soil layers(lower than 3.0 m from the surface)in arid shrubland communities in the global carbon balance.In addition,it provides the data support for revealing deep soil solid carbon potential,and offers scientific basis for the further research in the carbon cycle of terrestrial ecosystem.  相似文献   

2.
采用商河县2010年耕地地力评价有机质采样点的数据,运用GIS和地统计学相结合的方法,研究了商河县土壤有机质的密度及储量,并按照土类统计分析了不同土壤类型间的有机碳密度及储量差异。研究表明,商河县土壤有机碳密度范围为1.69~5.17kg/m2,平均3.44kg/m2;有机碳储量为0.26×1010kg。按乡镇统计,有机碳密度最大值为玉皇庙镇3.65kg/m2,最小值为郑陆镇3.15kg/m2,有机碳储量最大值玉皇庙镇3.47×108 kg,最小值张坊乡0.92×108 kg;按土壤类型统计,有机碳密度最大的为湿潮土3.46kg/m2,最小为风沙土3.29kg/m2,有机碳储量最大为潮土10.38×108 kg,最小为褐土化潮土1.34×108 kg。  相似文献   

3.
亚热带泥炭地在水源涵养、碳储存和生物多样性等方面有着重要的保护价值。溶解有机碳(DOC)是泥炭地中容易受到外界扰动的一部分碳，在气候变化和人类活动的双重影响下，DOC可能通过降解或横向迁移从泥炭地中流失，潜在地威胁了泥炭地的碳储存功能。然而，目前对于亚热带泥炭地DOC如何响应季节性尺度的环境变化还缺乏深入的认识。以位于北亚热带的神农架大九湖泥炭地为研究对象，开展了季节尺度的泥炭孔隙水DOC浓度和紫外-可见吸收光谱特征以及环境参数的监测。结果显示，在大九湖泥炭地中，表层0~10 cm的泥炭孔隙水DOC浓度和光谱参数具有明显的季节差异性，DOC浓度和光谱参数还表现出明显的深度差异性。相关性分析显示，DOC浓度及紫外-可见吸收光谱参数直接受控于泥炭孔隙水的电导率和氨态氮浓度，可能还间接受到泥炭地水位和孔隙水硝态氮浓度等因素的影响。以上结果表明，在亚热带季风气候条件下，季节性水位波动引起的泥炭水化学参数和营养盐的变化，可能显著改变表层泥炭DOC动态，需要重视这种季节性波动对亚热带泥炭地碳储存能力以及生态功能的影响。   相似文献   

4.
Riverine carbon flux is an important component of the global carbon cycle. The spatial and temporal variations of organic and inorganic carbon were examined during both dry and wet seasons in the Yellow River estuary. Concentrations of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) in the Yellow River during dry seasons were higher than those during wet seasons. The effective concentrations of DOC (CDOC*) were higher than the observed DOC at zero salinity. This input of DOC in the Yellow River estuary was due to sediment desorption processes in low salinity regions. In contrast to DOC, the effective concentrations of DIC were 10% lower than the DIC measured at freshwater end, and the loss of DIC was caused by CaCO3 precipitation in low salinity region. Particulate organic carbon (POC) and particulate inorganic carbon (PIC) contents of the particles stabilized to constant values (0.5%±0.05% and 1.8%±0.2%, respectively) within the turbidity maximum zone (TMZ) and showed no noticeable seasonal variations. A rapid drop of PIC and rise of POC occurred simultaneously outside the TMZ due to an intense dilution of riverine inorganic-rich particles being transported into a pool of aquatic organic-poor particles outside the TMZ. Annually, the Yellow River transported 6.95×105 t of DIC, 0.64×105 t of DOC, 78.58×105 t of PIC and 2.29×105 t of POC to the sea.  相似文献   

5.
1INTRODUCTIONDesertification is one of the most serious land degrada-tion, which results in the deterioration of physical, che-mical, and biological characteristics of soils (UNEP, 1992). Soil organic carbon (SOC) was considered to be a key index in evaluation of soil quality, soil degradation and soil C sequestration(SCHLENGSINGER etal., 1990; FENG etal., 2002; WANG etal., 2003). Many researchers have reported the correlations among desertification restoration, soil C s…  相似文献   

6.
森林植被碳密度是衡量森林生态系统服务功能和产品供给功能高低的一个重要指标.本文以四川省石棉县为例,在森林资源二类调查数据的基础上,提出建立森林植被生物量、碳量及其密度GIS数据库,开展其碳密度分布知识发现的研究,从中发现了该县碳密度分布知识.该县有林地森林植被碳量达到364万t,冷杉、云杉、铁杉和桦木占总碳量的83％;...  相似文献   

7.
以鄂尔多斯盆地的延长下寺湾区中生界延长组长7段陆相泥页岩为研究对象,在样品实验数据分析和单井岩心观察的基础上,根据泥页岩的发育与分布特点和有机地球化学特征对陆相页岩气的泥页岩进行评价.结果表明:延长下寺湾区延长组长7段泥页岩主要为浅湖—深湖相沉积,泥页岩累计厚度适宜,有机质类型以Ⅱ1为主,有机质丰度较高,具备页岩气生成的物质基础,有机质演化主要处于成熟阶段.分析美国海相产气页岩与中国陆相产气页岩的综合特征,长7段泥页岩脆性矿物质量分数大于25%,有利于储层的后期改造.相对美国储层物性较好的页岩,根据现场解析法测得的长7段泥页岩含气量较高(平均为4.5m3/t),埋深适中,分布稳定,具有勘探潜力和开发前景.  相似文献   

8.
本文以贵州省东南部三州为研究区,运用连续生物量转换因子法和平均生物量法,通过2010年森林清查小班数据,建立了24类优势树种的森林植被碳密度与林龄之间的关系。同时,估算了1990-2010年间贵州省东南部森林植被生物量及其碳蓄积量,分析了碳蓄积量的时空变化特征,并预测出2050年该区域森林植被的固碳潜力。结果显示：（1）2010年贵州省东南部森林植被碳蓄积量为106.22 TgC,占贵州省森林植被碳蓄积量的63.01%,占全国森林植被碳蓄积量的1.36%;平均碳密度32.44 MgC/hm2,是贵州省森林植被平均碳密度的93%,全国森林植被平均碳密度的76%,碳密度空间分布呈现由西部向东部增加趋势且东部高于平均水平。（2）1990-2000年间森林植被碳蓄积量增加了30.67 TgC;2000-2010年间森林植被碳蓄积量增加了49.55 TgC,其中,退耕还林导致森林植被碳蓄积量增加了31.09 TgC。（3）以2010年为基准年,假设40 a后贵州省东南部森林面积保持稳定,且不考虑轮伐期的未来情景下,至2050年该区域森林植被碳蓄积量将达到153.38 TgC,其增量可达47.16 TgC,表明贵州省东南部森林具有较大的碳增汇潜力。  相似文献   

9.
Biomass carbon sequestration by planted forests in China   总被引：2，自引：1，他引：1  
The planted forest area and carbon sequestration have increased significantly in China, because of large-scale reforestation and afforestation in the past decades. In this study, we developed an age-based volume-to-biomass method to estimate the carbon storage by planted forests in China in the period of 1973–2003 based on the data from 1209 field plots and national forest inventories. The results show that the total carbon storage of planted forests was 0.7743 Pg C in 1999–2003, increased by 3.08 times since the early 1970s. The carbon density of planted forests varied from 10.6594 Mg/ha to 23.9760 Mg/ha and increased by 13.3166 Mg/ha from 1973–1976 to 1999–2003. Since the early 1970s, the planted forests in China have been always a carbon sink, and the annual rate of carbon sequestration was 0.0217 Pg C/yr. The carbon storage and densities of planted forests varied greatly in space and time. The carbon storage of Middle South China was in the lead in all regions, which accounted for 23%–36% of national carbon storage. While higher C densities (from 17.79 Mg/ha to 26.05 Mg/ha) were usually found in Northeast China. The planted forests in China potentially have a high carbon sequestration since a large part of them are becoming mature and afforestation continues to grow.  相似文献   

10.
Rapid urbanization results in the conversion of natural soil to urban soil,and consequently,the storage and density of the soil carbon pools change.Taking Chongqing Municipality of China as a study case,this investigation attempts to better understand soil carbon pools in hilly cities.First,the vegetated areas in the study area were derived from QuickBird images.Then,topsoil data from 220 soil samples(0-20 cm) in the vegetated areas were collected and their soil organic carbon(SOC) densities were analyzed.Using the Kriging interpolation method,the spatial pattern of SOC was estimated.The results show that the SOC density exhibited high spatial variability in the urban topsoil of Chongqing.First,the SOC density in topsoil decreased according to slope in the order 2°-6° < 25°-90° < 0°-2° < 6°-15° < 15°-25°.Second,the newly developed areas during 2001-2010 had a lower SOC density than the areas built before 1988.Third,urban parks and gardens had a higher SOC density in topsoil,residential green land followed,and scattered street green land ranked last.For hilly cities,the variability of terrain affects the distribution of SOC.The Kriging results indicate that Kriging method combining slope with SOC density produced a high level of accuracy.The Kriging results show that the SOC density to the north of the Jialing River was higher than the south.The vegetated areas were estimated to amount to 73.5 km2 across the study area with an SOC storage of 0.192 Tg and an average density of 2.61 kg/m2.  相似文献   

11.
Soil organic carbon (SOC) was considered to be a key index in evaluation of soil degradation and soil C sequestration. To discuss the spatial-temporal dynamics of SOC in arable layer in reversed desertification area, a case study was conducted in Yulin City, Shaanxi Province, China. Data of SOC were based on general soil survey in 1982 and repeated soil sampling in 2003. Soil organic carbon content (SOCC) was determined by K2Cr3O2-FeSO4 titration method, and soil organic carbon density (SOCD) was calculated by arithmetic average and area weighted average method, respectively. On average, SOCC and SOCD of the arable layer in the study area from 1982 to 2003 had increased 0.5 Ig/kg and 0.16kg/m2, respectively. Considering main soil types, the widest distributed Arid-Sandic Entisols had lowest values and increments of SOCC and SOCD during the study period; while the second widest Los-Orthic Entisols had higher values and increments of SOCC and SOCD, compared to the mean values of the whole region. The results indicated that reversed desertification process was due to the modification of land use and management practices, such as natural vegetation recovery, planting grass, turning arable land to grassland, and soil and water conservation etc., which can improve SOCC and SOCD and thus enhance soil C sequestration.  相似文献   

12.
Land use changes are known to alter soil organic carbon （SOC） and microbial properties, however, information about how conversion of natural forest to agricultural land use as well as plantations affects SOC and microbial properties in the Changbai Moun- tains of Northeast China is meager. Soil carbon content, microbial biomass carbon （MBC）, basal respiration and soil carbon mineraliza- tion were studied in five selected types of land use： natural old-growth broad-leaved Korean pine mixed forest （NF）; spruce plantation （SP） established following clear-cutting of NF; cropland （CL）; ginseng farmland （GF） previously under NF; and a five-year Mongolian oak young forest （YF） reforested on an abandoned GF, in the Changbai Mountains of Northeast China in 2011. Results showed that SOC content was significantly lower in SP, CL, GF, and YF than in NF. MBC ranged from 304.4 mg/kg in CL to 1350.3 mg/kg in NF, which was significantly higher in the soil of NF than any soil of the other four land use types. The SOC and MBC contents were higher in SP soil than in CL, GF, and YF soils, yielding a significant difference between SP and CL. The value of basal respiration was also higher in NF than in SP, CL, GF, and YF. Simultaneously, higher values of the metabolic quotient were detected in CL, GF, and YF soils, indicat- ing low substrate utilization of the soil microbial community compared with that in NF and SP soil. The values of cumulative mineral- ized carbon and potentially mineralized carbon （Co） in NF were significantly higher than those in CL and GF, while no significant dif- ference was observed between NF and SP. In addition, YF had higher values of Co and C mineralization rate compared with GF. The results indicate that conversion from NF into agricultural land （CL and GF） uses and plantation may lead to a reduction in soil nutrients （SOC and MBC） and substrate utilization efficiency of the microbial community. By contrast, soils below SP were more conducive to the preservation of soil organic matter, which was reflected in the comparison of microbial indicators among CL, GF, and YF land uses. This study can provide data for evaluating soils nutrients under different land use types, and serve as references for the rational land use of natural forest in the study area.  相似文献   

13.
Water samples were collected and analyzed in high water season (July 1997) and in middle water season (October, 1997) from two main lower reach gauge stations of the Zhujiang (Pearl) River, namely Hekou and Makou, respectively. Content of particulate organic carbon is always higher than that of dissolved organic carbon in both seasons, which is obviously different from the global average pattern, i.e. dissolved organic carbon is the dominant component of the transported riverine organic carbon. The content of dissolved and particulate organic carbon changes with the water levels in a direct ratio. The percentage of organic carbon in total suspended substance changes with the content of total suspended substance in an inverse ratio. The more intense is the soil erosion in the drainage, the more concentrated is the riverine organic carbon in the river. The contribution of autochthonous organic carbon is large in high water season than in middle water season. Fundation item: This project was supported financially by the National Natural Science Foundation of China (No. 49901002), the key funds of resources and eco-environmental research of the CAS (No. KZ952-J1-402), a funds of the state key laboratory of organic geochemistry, and Guangdong Province Science Funds (No. 984131). Biography: Gao Quan-zhou (1965 —), male, a native of Anhui Province, associate professor. His research interests are geomorphology and Quaternary geochemistry.  相似文献   

14.
The concentrations of organic carbon (OC) and elemental carbon (EC)in total suspended particle (TSP) were investigated at Ny-(A)lesund, Svalbard in a two-week campaign. The levels of OC and EC are 0.86 ±0.27 μgm-3 (mean±standard deviation) and 0. 19±0.10 μgm-3 , respectively. Back trajectory analysis of air masses arriving at Ny-(A)lesund reveals that long-range transport of polluted air play insignificant role in OC and EC levels, to which the potential influence of the local contamination were ascribed. The average OC/EC ratio is 5.41,suggesting the presence of the secondary organic aerosols. The estimated secondary organic carbon (SOC) in TSP is 0.59 μg/m3 , accounting for 64% of the total organic carbon.  相似文献   

15.
In the Sanjiang Plain,Northeast China,the natural wetland is undergoing a rapid conversion into agricultural land,which has resulted in drastic ecological changes in the region. To investigate the effects of different land uses on soil labile organic carbon,soils of Calamagrostis angustifolia wetland,Carex lasiocarpa wetland,dry farmland,paddy field,forest land and abandoned cultivated land were collected for measuring the contents of soil microbial biomass carbon (MBC),dissolved organic carbon (DOC),readil...  相似文献   

16.
This study was conducted to explore the effects of topography and land use changes on particulate organic carbon(POC),particulate total nitrogen(PTN),organic carbon(OC) and total nitrogen(TN) associated with different size primary particle fractions in hilly regions of western Iran.Three popular land uses in the selected site including natural forest(NF),disturbed forest(DF) and cultivated land(CL) and three slope gradients(0-10 %,S1,10-30 %,S2,and 30-50%,S3) were employed as the basis of soil sampling.A total of 99 soil samples were taken from the 0-10 cm surface layer in the whole studied hilly region studied.The results showed that the POC in the forest land use in all slope gradients was considerably more than the deforested and cultivated lands and the highest value was observed at NF-S1 treatment with 9.13%.The values of PTN were significantly higher in the forest land use and in the down slopes(0.5%) than in the deforested and cultivated counterparts and steep slopes(0.09%) except for the CL land use.The C:N ratios in POC fraction were around 17-18 in the forest land and around 23 in the cultivated land.In forest land,the silt-associated OC was highest among the primary particles.The enrichment factor of SOC,EC,was the highest for POC.For the primary particles,EC of both primary fractions of silt and clay showed following trend for selected land uses and slope gradients:CL> DF> NF and S3 > S2> S1.Slope gradient of landscape significantly affected the OC and TN contents associated with the silt and clay particles,whereas higher OC and TN contents were observed in lower positions and the lowest value was measured in the steep slopes.Overall,the results showed that native forest land improves soil organic carbon storage and can reduce the carbon emission and soil erosion especially in the mountainous regions with high rainfall in west of Iran.  相似文献   

17.
A research trial with four land management practices, i.e., traditional tillage-fallow (TTF), traditional tillage-wheat (TTW), conservation tillage-fallow (CTF) and conservation tillage-wheat (CTW), was sampled in the 15th year after its establishment to assess the effects of different management practices on labile organic carbon fractions (LOCFs), such as easily oxidizable organic carbon (EOC), dissolved organic carbon (DOC), particulate organic carbon (POC) and microbial biomass carbon (MBC) in a typical paddy soil, Chongqing, Southwest China. The results indicated that LOCFs were significantly influenced by the combination of no-tillage, ridge culture and crop rotation. And, different combination patterns showed different effectiveness on soil LOCFs. The effects of no-tillage, ridge culture and wheat cultivation on EOC, DOC, POC and MBC mainly happened at 0–10cm. At this depth, soil under CTW had higher EOC, DOC, POC and MBC contents, compared to TTF, TTW and CTF, respectively. Moreover, the contents of LOCFs for different practices generally decreased when the soil depth increased. Our findings suggest that the paddy soil in Southwest China could be managed to concentrate greater quantities of EOC, DOC, POC and MBC. Foundation item: Under the auspices of Key Project of National Natural Science Foundation of China (No. 40231016)  相似文献   

18.
Investigation of dissolved organic carbon (DOC) and particulate organic carbon (POC) at 12 stations in Yantal Sishili Bay in May, August, and November of 1997 and March and May of 1998 showed that DOC concentrations varied from 1.14 mg/L to 5.35 mg/L; that the average values at all staticrLs ineach entise varied from 1.52 mg/L to 2.12 mg/L; that POC concentrafions varied from 0.049 mg/L to 1.411mg/L; and averaged 0.159 mg/L to 0.631 mg/L in each cruise. Horizontal distribution of DOC was influ-enced by factors such as continental input, organism activity, temperature, aquieulture environment, etc. The higher POC concentration occurred along the coast. The vertical distribution of DOC and POC changed obviously in spring and summer, but not obviously in autumn and winter. DOC concentration was highest in summer and POC in spring; both were lowest in winter. The seasonal change of DOC was con-sistent with primary productivity seasonal variation, and that of POC was consistent with ehlorophyll-a sea-sanal variation. The seasonal change trend of the C/N ratio of dissolved organic matter was obvious, but the C/N ratio of particulate organic matter had no such trend.  相似文献   

19.
ＩＮＴＲＯＤＵＣＴＩＯＮＥｓｔｕａｒｉｅｓｃｏｍｐｒｉｓｅａｍａｊｏｒｂｉｏｇｅｏｃｈｅｍｉｃａｌｉｎｔｅｒｆａｃｅｃｏｎｎｅｃｔｉｎｇｔｈｅｌａｎｄａｎｄｔｈｅｓｅａ (Ｍａｎ ｔｏｕｒａ,1 987) .Ｔｈｅｂｅｈａｖｉｏｒａｎｄｆａｔｅｏｆａｐａｒｔｉｃｕｌａｒｒｉｖｅｒ ｂｏｒｎｅｓｕｂｓｔａｎｃｅｉｎｔｒｏｄｕｃｅｄｉｎｔｏａｎｅｓｔｕａｒｙｉｓｄｅｔｅｒｍｉｎｅｄｔｏａｌａｒｇｅｅｘｔｅｎｔｂｙｔｈｅｂｉｏｇｅｏｃｈｅｍｉｃａｌｐｒｏｐｅｒｔｉｅｓｏｆｔｈｅｓｕｂｓｔａｎｃｅａｓｗｅｌｌａｓｐ…  相似文献   

20.
The urban population and urbanized land in China have both increased markedly since the 1980s. Urban and suburban developments have grown at unprecedented rates with unknown consequences for ecosystem functions. In particular, the effect of rapid urbanization on the storage of soil carbon has not been studied extensively. In this study, we compared the soil carbon stocks of different land use types in Beijing Municipality. We collected 490 top-soil samples （top 20 cm） from urban and suburban sites within the Sixth Ring Road of Beijing, which cover approximately 2400 km2, and the densities of soil organic carbon （SOC）, soil inorganic carbon （SIC）, and total carbon （TC） were analyzed to determine the spatial distribution of urban and suburban soil carbon characteristics across seven land use types. The results revealed significant differences in soil carbon densities among land use types. Additionally, urban soil had significantly higher SOC and SIC densities than suburban soil did, and suburban shelterbelts and productive plantations had lower SIC densities than the other land use types. The comparison of coefficients of variance （CVs） showed that carbon content of urban topsoil had a lower variability than that of suburban topsoil. Further findings revealed that soil carbon storage increased with built-up age. Ur- ban soil built up for more than 20 years had higher densities of SOC, SIC and TC than both urban soil with less than 10 years and sub- urban soil. Correlation analyses indicated the existence of a significantly negative correlation between the SOC, SIC, and TC densities of urban soil and the distance to the urban core, and the distance variable alone explained 23.3% of the variation of SIC density and 13.8% of the variation of TC density. These results indicate that SOC and SIC accumulate in the urban topsoil under green space as a result of the conversion of agricultural land to urban land due to the urbanization in Beijing.  相似文献   

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