温度、水分对湿地土壤有机碳矿化的影响

采用密闭培养法,研究了小叶章(Deyeuxia angustifolia)湿地土壤有机碳的矿化动态,探讨了温度和水分条件对有机碳矿化的影响.结果表明:湿地土壤有机碳在培养初期(0～2 d)矿化速率较高,之后矿化速率逐渐降低;33 d培养期间,表层(0～10 cm)土壤的总矿化量为1.59～2.62 mg C·g-1,为下层(10～100 cm)的4～22倍;温度升高10℃使总矿化量分别增加60%～210%(75%WHC)和30%～200%(淹水);一级动力学方程能较好地描述湿地土壤有机碳矿化动态,其C0值随土壤深度呈指数递减变化,且C0和C0/SOC值均随温度的升高而升高;不同深度土壤Q10值分别变化为1.7～3.1(75% WHC)和1.2～3.0(淹水),且与土壤深度之间存在明显的二次抛物线相关;土壤深度、培养温度对湿地土壤有机碳矿化具有显著影响,而水分处理对有机碳矿化的影响不显著.     

Short term effects of radiata pine and selected pasture species on soil organic phosphorus mineralisation

Silvopastoral systems comprise part of the continued expansion of conifer plantings on grassland in New Zealand. Greater understanding of the short term dynamics of soil organic P in such systems will further our knowledge about soil carbon and phosphorus relationships which will enable improved nutrient management in the field. A glasshouse experiment was carried out to examine the short-term effects (36 weeks) of combinations of radiata pine (Pinus radiata), lucerne (Medicago sativa L.) and perennial ryegrass (Lolium perenne L.) grown in the same soil type with a range of carbon (C) and phosphorus (P) levels on plant P uptake and the specific mineralisation rate (SMR). The SMR is defined as net mineralisation rate (i.e. gross mineralisation less microbial and geochemical uptake) and calculated from organic P decline as a percentage of organic P in the original soil before planting. This included an investigation of the effect of tree ectomycorrhizal (EM) hyphae on soil organic P. Plant P uptake was positively correlated with water soluble organic carbon (WSOC) and SMR, which in turn was closely related to soil C levels. The soils with high WSOC and C levels (which also contained high levels of labile inorganic and organic P) enabled high P uptake. Although P uptake was the greatest under radiata pine, the trees tended to deplete inorganic P to a lesser extent than the forages. When tree and forage species were combined, P uptake by forages was similar to when the forages were grown alone. The various soil and plant treatments significantly affected SMR. The two low C soils, showed the greatest organic P mineralisation while a high C soil, which contained significant levels of bicarbonate extracted inorganic P at planting and was under a long established undisturbed pasture, showed the least mineralisation. Trees grown alone showed the greatest SMR, EM hyphae and trees with lucerne were slightly lower than trees alone, while the forages showed the lowest SMR. The findings of this study showed that changes in organic P are strongly influenced by interactions between plant species (radiata pine, lucerne, ryegrass) and soil properties as determined by land use and management.     

白洋淀湿地区土壤有机碳密度及储量的空间分布特征

湿地生态系统碳储量是陆地生态系统碳循环的重要组成部分,提供重要的生态系统服务功能。白洋淀湿地是国家重要生态湿地和华北平原最大的淡水湿地,同时是雄安新区的核心水系,湿地区土壤碳储量的估算研究将为湿地生态系统服务评估和湿地生态恢复提供数据支撑。研究通过对白洋淀湿地7种不同地类的105个土壤剖面进行分层取样,揭示了其湿地土壤有机碳密度及储量的空间分布特征,结果表明:(1)白洋淀湿地区土壤有机碳含量整体偏低,在各层土壤中,淹水芦苇湿地的有机碳含量均显著高于其他植被类型,约为其他类型土壤碳含量的3倍左右。(2)在各植被类型中土壤有机碳含量均以表层(0—20 cm)最高,其分配比例均集中在30%左右,随着土壤剖面深度的增加,湿地土壤的有机碳含量逐渐减少。(3)不同植被类型土壤有机碳含量与土壤有机碳密度的差异显著,具体表现为:乔木园地<旱地<常绿针叶林<落叶阔叶林<水田<台田芦苇<淹水芦苇。(4)根据估算,白洋淀湿地区的土壤有机碳储量约为5816.77×10³Mg。随着雄安新区环境治理工作的推进,白洋淀湿地区生态系统固碳将呈现持续向好态势,结...     

芦苇湿地土壤有机碳和全氮含量的垂直分布特征

利用元素分析仪,测定了芦苇湿地不同层次土壤有机碳和全N的变化.结果表明,土壤有机碳、全N及C/N随土壤深度的增加呈下降趋势.对不同月份(7、8、9和10月)而言,有机碳、全N及C/N比累积峰位于不同的土层中.土壤温度、水分及芦苇生长状况是引起分异的重要因子.7、8和10月份芦苇湿地不同层次土壤有机碳与全N呈显著相关(R²=0.73、0.73、0.71),而9月份芦苇湿地不同层次土壤有机碳与全N之间的相关性相对较差(R²=0.41).土壤C/N与土壤有机碳、全N均呈负相关,但C/N与全N的相关性强于土壤有机碳,说明C/N的大小主要决定于全N含量.     

From forest to cropland and pasture systems: a critical review of soil organic carbon stocks changes in Amazonia

The impact of deforestation on soil organic carbon (SOC) stocks is important in the context of climate change and agricultural soil use. Trends of SOC stock changes after agroecosystem establishment vary according to the spatial scale considered, and factors explaining these trends may differ sometimes according to meta‐analyses. We have reviewed the knowledge about changes in SOC stocks in Amazonia after the establishment of pasture or cropland, sought relationships between observed changes and soil, climatic variables and management practices, and synthesized the δ¹³C measured in pastures. Our dataset consisted of 21 studies mostly synchronic, across 52 sites (Brazil, Colombia, French Guiana, Suriname), totalling 70 forest–agroecosystem comparisons. We found that pastures (n = 52, mean age = 17.6 years) had slightly higher SOC stocks than forest (+6.8 ± 3.1 %), whereas croplands (n = 18, mean age = 8.7 years) had lower SOC stocks than forest (?8.5 ± 2.9 %). Annual precipitation and SOC stocks under forest had no effect on the SOC changes in the agroecosystems. For croplands, we found a lower SOC loss than other meta‐analyses, but the short time period after deforestation here could have reduced this loss. There was no clear effect of tillage on the SOC response. Management of pastures, whether they were degraded/nominal/improved, had no significant effect on SOC response. δ¹³C measurements on 16 pasture chronosequences showed that decay of forest‐derived SOC was variable, whereas pasture‐derived SOC was less so and was characterized by an accumulation plateau of 20 Mg SOC ha^?1 after 20 years. The large uncertainties in SOC response observed could be derived from the chronosequence approach, sensitive to natural soil variability and to human management practices. This study emphasizes the need for diachronic and long‐term studies, associated with better knowledge of agroecosystem management.     

Feeding minerals to cattle on pasture

Mineral deficiencies and imbalances for cattle are reported from almost all regions of the world. The mineral elements most likely to be lacking under grazing conditions for ruminants are Ca, P, Na, Co, Cu, I, Se and Zn. In some regions, under specific conditions, Mg, K, Fe and Mn may be deficient and excesses of F, Mo and Se can be extremely detrimental. In most countries of the world, the principal means by which cattle producers attempt to meet mineral requirements of their grazing herds is through use of free-choice dietary minerals. As a low cost insurance to provide adequate mineral nutrition, a modified ‘complete’ mineral supplement should be available free-choice. Calcium, Cu or Se, when in excess, can be more detrimental to cattle production than any benefit derived by providing a mineral supplement. The major disadvantage to free-choice minerals is lack of uniform consumption by animals. Factors influencing consumption of mineral mixtures include: (1) soil fertility and forage type, (2) season of year, (3) available energy and protein, (4) individual requirements, (5) salt content of water, (6) palatability of mineral mixture, (7) availability of fresh minerals and (8) physical form of minerals. Safe, biologically available and palatable forms of minerals, at a fair price, allow both the user and manufacturer to realize a profit from their use. Mineral supplements need to be evaluated for accuracy of formulation and suitability for cattle. Most studies have shown positive responses of mineral chelates and complexes when compared to inorganic sources.     

China's wetland soil organic carbon pool: New estimation on pool size,change, and trajectory

Robust estimates of wetland soil organic carbon (SOC) pools are critical to understanding wetland carbon dynamics in the global carbon cycle. However, previous estimates were highly variable and uncertain, due likely to the data sources and method used. Here we used machine learning method to estimate SOC storage and their changes over time in China's wetlands based on wetland SOC density database, associated geospatial environmental data, and recently published wetland maps. We built a database of wetland SOC density in China that contains 809 samples from 181 published studies collected over the last 20 years as presented in the published literature. All samples were extended and standardized to a 1-m depth, on the basis of the relationship between SOC density data from soil profiles of different depths. We used three different machine learning methods to evaluate their robustness in estimating wetland SOC storage and changes in China. The results indicated that random forest model achieved accurate wetland SOC estimation with R² being .65. The results showed that average SOC density of top 1 m in China's wetlands was 25.03 ± 3.11 kg C m⁻² in 2000 and 26.57 ± 3.73 kg C m⁻² in 2020, an increase of 6.15%. SOC storage change from 4.73 ± 0.58 Pg in 2000 to 4.35 ± 0.61 Pg in 2020, a decrease of 8.03%, due to 13.6% decreased in wetland area from 189.12 × 10³ to 162.8 × 10³ km² in 2020, despite the increase in SOC density during the same time period. The carbon accumulation rate was 107.5 ± 12.4 g C m⁻² year⁻¹ since 2000 in wetlands with no area changes. Climate change caused variations in wetland SOC density, and a future warming and drying climate would lead to decreases in wetland SOC storage. Estimates under Shared Socioeconomic Pathway 1-2.6 (low-carbon emissions) suggested that wetland SOC storage in China would not change significantly by 2100, but under Shared Socioeconomic Pathway 5-8.5 (high-carbon emissions), it would decrease significantly by approximately 5.77%. In this study, estimates of wetland SOC storage were optimized from three aspects, including sample database, wetland extent, and estimation method. Our study indicates the importance of using consistent SOC density and extent data in estimating and projecting wetland SOC storage.     

艾比湖湿地土壤有机碳及储量空间分布特征

土壤碳储量的研究是全球碳循环研究的热点,土壤碳库的变化对全球气候变暖、维护生态平衡都有着重要的意义。新疆的艾比湖湿地是干旱区典型的盐湖湿地,为探明该湿地有机碳特性及储量,选择艾比湖湿地1m深度的土壤作为研究对象,测试有机碳含量后,对艾比湖湿地土壤有机碳特性进行分析并分层定量测算有机碳储量,结果显示:(1)艾比湖湿地土壤有机碳整体偏低,随土层加深,含量依次递减的规律比较显著。湿地7种不同植被覆盖类型的土壤有机碳含量垂直空间变异性差异明显,其中荒漠河岸林、盐化草甸、小乔木荒漠大多属于强变异,而其它植被覆盖的土壤类型多属于中等变异。(2)艾比湖湿地7种不同植被类型土壤有机碳含量在相同土层的分布特征为:有机碳集中分布在浅表层(0—20 cm),从40 cm以下变幅缓慢,分布较为均匀。不同植被类型土壤有机碳在不同土层的分配比例差异比较明显,但表层(0—20 cm)大多占到30%以上。(3)艾比湖湿地土壤有机碳储量排序依次为小乔木荒漠盐化草甸干涸湖底灌木荒漠盐生灌丛荒漠河岸林寒湿性针叶林。湿地有机碳蓄积总量为7086862.83 kgC。上述研究结果可为新疆干旱区湿地生态系统恢复、保护与科学管理提供科技支撑。     

Afforestation with Norway spruce on a subalpine pasture alters carbon dynamics but only moderately affects soil carbon storage

There is a strong trend toward reforestation of abandoned grasslands in alpine regions which may impact the carbon balance of alpine ecosystems. Here, we studied the effects of afforestation with Norway spruce (Picea abies L.) on an extensively grazed subalpine pasture in Switzerland on soil organic carbon (SOC) cycling and storage. Along a 120-year long chronosequence with spruce stands of 25, 30, 40, 45, and >120 years and adjacent pastures, we measured tree biomass, SOC stocks down to the bedrock, natural ¹³C abundances, and litter quality. To unravel controls on SOC cycling, we have monitored microclimatic conditions and quantified SOC decomposability under standardized conditions as well as soil respiration in situ. Stocks of SOC were only moderately affected by the afforestation: in the mineral soil, SOC stocks transiently decreased after tree establishment, reaching a minimum 40–45 years after afforestation (?25 %) and increased thereafter. Soils of the mature spruce forest stored the largest amount of SOC, 13 % more than the pasture soils, mainly due to the accumulation of an organic layer (23 t C ha^?1). By comparison, C accumulated in the tree biomass exceeded the SOC pool by a factor of three in the old forest. In contrast to the small impact on C storage, afforestation strongly influenced the composition and quality of the soil organic matter (SOM). With increasing stand age, δ¹³C values of the SOM became consistently more positive, which can be interpreted as a gradual replacement of grass- by spruce-derived C. Fine roots of spruce were enriched in ¹³C, in lignin and had a higher C/N ratio in comparison to grass roots. As a consequence, SOM quality as indicated by the lower fraction of readily decomposable (labile) SOM and higher C:N ratios declined after the land-use change. Furthermore, spruce plantation induced a less favorable microclimate for microbial activity with the average soil temperature during the growing season being 5 °C lower in the spruce stands than in the pasture. In situ soil respiration was approximately 50 % lower after the land use conversion, which we primarily attribute to the colder conditions and the lower SOM quality, but also to drier soils (?25 %) and to a decreased fine root biomass (?40 %). In summary, afforestation on subalpine pastures only moderately affected SOC storage as compared to the large C sink in tree biomass. In contrast, SOC cycling rates strongly decreased as a result of a less favorable microclimate for decomposition of SOM, a lower C input by roots, and a lower litter quality.     

沙田湖人工湿地植物-土壤有机碳库

在人工构建的用于处理水产养殖废水的表面流和水平潜流湿地复合系统中,对湿地植物各组织、湿地表层土壤(0～10 cm)、湿地植物根际土壤的有机碳含量季节变化规律进行研究,并对湿地植物表层土壤和湿地植物对有机碳的固定作用进行了分析.结果表明:湿地植物地上部分组织固定的有机碳含量表现为在生长期迅速增加,8月较高,进入成熟期(11月)后保持稳定,8月有机碳含量与5月有显著性差异、与11月差异不显著;湿地植物地下部分组织固定的有机碳含量低于地上部分,但季节变化与地上部分相似,5月含量最小,8月达到一个较高的值,11月与8月有机碳含量差异不大.植物进入生长期后,湿地表层土壤有机碳含量显著高于湿地上无植物时期,各湿地植物根际土有机碳含量均高于表层土,但差异不显著(睡莲除外).湿地表层土壤有机碳密度介于0.96～1.67 kg·m-2,受植物种类、植物生长季节等因素的影响.根据湿地面积和表层土壤有机碳含量,估算出沙田湖人工湿地(表面流湿地部分面积为3592 m2)0～10 cm土壤有机碳总量为5.61 t,通过植物吸收每年固定的碳量为10.34 t.     

Impact of rainfall gradient on aboveground biomass and soil organic carbon dynamics of forest covers in Gujarat,India

Alterations in precipitation are affecting forest ecosystems’ soil carbon cycling. To understand how shifts in rainfall may alter these carbon pools, above-ground biomass (AGB), soil organic carbon (SOC), and microbial biomass carbon (MBC) of tropical forest covers were measured across a rainfall gradient (543–1590 mm) in Gujarat (India), a state falling under semi arid to tropical dry–wet conditions. Species diversity, tree density and soil texture were also measured. Field visits and data collection were carried out for 2 years (2009–2011) in 95 plots of 250 × 250 m in the forest covers across four distinct rainfall zones (RFZs). Data analysis showed that differences seen in the values of the measured parameters across the RFZs are statistically significant (P < 0.05). Positive correlations were observed between mean annual precipitation (MAP) and tree density, species diversity, AGB, SOC, and MBC. Across the RFZs, AGB ranged between 0.09 and 168.28 Mg ha^?1; SOC values (up to 25 cm soil depth) varied between 2.94 and 147.84 Mg ha^?1. Soil texture and MBC showed a significant impact on the dynamics of SOC in all the RFZs. MBC is more influenced by SOC rather than AGB. Both vegetation type and MAP have an important role in the regulation of SOC in tropical soils. Together, these results reveal complex carbon cycle responses are likely to occur in tropical soils under altered rainfall regimes.     

Soil organic carbon dynamics jointly controlled by climate,carbon inputs,soil properties and soil carbon fractions

Soil organic carbon (SOC) dynamics are regulated by the complex interplay of climatic, edaphic and biotic conditions. However, the interrelation of SOC and these drivers and their potential connection networks are rarely assessed quantitatively. Using observations of SOC dynamics with detailed soil properties from 90 field trials at 28 sites under different agroecosystems across the Australian cropping regions, we investigated the direct and indirect effects of climate, soil properties, carbon (C) inputs and soil C pools (a total of 17 variables) on SOC change rate (r_C, Mg C ha^?1 yr^?1). Among these variables, we found that the most influential variables on r_C were the average C input amount and annual precipitation, and the total SOC stock at the beginning of the trials. Overall, C inputs (including C input amount and pasture frequency in the crop rotation system) accounted for 27% of the relative influence on r_C, followed by climate 25% (including precipitation and temperature), soil C pools 24% (including pool size and composition) and soil properties (such as cation exchange capacity, clay content, bulk density) 24%. Path analysis identified a network of intercorrelations of climate, soil properties, C inputs and soil C pools in determining r_C. The direct correlation of r_C with climate was significantly weakened if removing the effects of soil properties and C pools, and vice versa. These results reveal the relative importance of climate, soil properties, C inputs and C pools and their complex interconnections in regulating SOC dynamics. Ignorance of the impact of changes in soil properties, C pool composition and C input (quantity and quality) on SOC dynamics is likely one of the main sources of uncertainty in SOC predictions from the process‐based SOC models.     

Impact of drying and re-wetting on N,P and K dynamics in a wetland soil

As increased nutrient availability due to drainage is considered a major cause of eutrophication in wetlands rewetting of drained wetlands is recommended as a restoration measure. The effect of soil drying and rewetting on the contribution of various nutrient release or transformation processes to changed nutrient availability for plants is however weakly understood. We measured effects of soil drying and re-wetting on N mineralization, and denitrification, as well as on release of dissolved organic nitrogen (DON), phosphorus, and potassium in incubated soil cores from a wet meadow in southern Sweden. Additionally, the impact of re-wetting with sulphate-enriched water was studied. Soil drying stimulated N mineralization (3 times higher) and reduced denitrification (5 times lower) compared to continuously wet soil. In the wet cores, denitrification increased to 20 mg N m^–2 d^–1, which was much higher than denitrification measured in the field. In the field, increased inorganic-N availability for plants due to drainage seemed primarily to be caused by increased N mineralization, and less by decreased denitrification. Soil drying also stimulated the release of DON and K, but P release was not affected. Re-wetting of dried soil cores strongly stimulated denitrification (up to 160 mg N m^–2 d^–1), but N mineralization was not significantly decreased, neither were DON or K release. In contrast, the extractable P pool increased upon soil wetting. Re-wetting with sulphate-enriched water had no effect on any of the nutrient release or transformation rates. We conclude that caution is required in re-wetting of drained wetlands, because it may unintendently cause internal eutrophication through an increased P availability for plants.     

Contribution of invasive species Spartina alterniflora to soil organic carbon pool in coastal wetland: Stable isotope approach

Spartina alterniflora was introduced into China because of its strong sedimentation promotion ability, currently, it became one of the most invasive species along coastal areas. Most researches focused on its high productivity which directly increased soil carbon (C) input. However, little is known about its indirect contribution to soil carbon via increased sedimentation.     

Soil organic carbon dynamics: variability with depth in forested and deforested soils under pasture in Costa Rica

Dynamics of soil organic carbon (SOC) inchronosequences of soils below forests that had beenreplaced by grazed pastures 3–25 years ago, wereinvestigated for two contrasting soil types (AndicHumitropept and Eutric Hapludand) in the Atlantic Zoneof Costa Rica. By forest clearing and subsequentestablishment of pastures, photosynthesis changes froma C-3 to a C-4 pathway. The accompanying changes inC-input and its ¹³C and ¹⁴Csignals, were used to quantify SOC dynamics. C-input from rootturnover at a pasture site was measured by sequentialharvesting and ¹⁴C-pulse labelling. With aspatial resolution of 5 cm, data on total SOC,¹³C and ¹⁴C of soil profileswere interpreted with a model that distinguishes threepools of SOC: active C, slow C and passive C,each with a 1^-st order decomposition rate(k_a, k_s and k_p). The modelincludes carbon isotope fractionation and depth-dependentdecomposition rates. Transport of C between soillayers was described as a diffusion process, whichaccounts for physical and biotic mixing processes.Calibrated diffusion coefficients were 0.42 cm²yr-¹ for the Humitropept and 3.97 cm²yr-¹ for the Hapludand chronosequence.Diffusional transport alone was insufficient foroptimal simulation; it had to be augmented bydepth-dependent decomposition rates to explain thedynamics of SOC, ¹³C and¹⁴C. Decomposition rates decreasedstrongly with depth. Upon increased diffusion,differences between calibrated decomposition rates ofSOC fractions between surface soils and subsoilsdiminished, but the concept of depth-dependentdecomposition had to be retained, to obtain smallresiduals between observed and simulated data. At areference depth of 15–20 cm k_s was 90 yr-¹in the Humitropept and 146 yr-¹ in the Hapludand.Slow C contributed most to total organic C in surfacesoils, whereas passive C contributed most below 40 cmdepth. After 18–25 years of pasture, net loss of C was2180 g C m-² for the Hapludand and 150 g m-²for the Humitropept soil.     

Effects of external nitrogen additions on soil organic carbon dynamics and the mechanism

What would be the impact of external nitrogen additions on soil carbon, an issue still under debating, as reported experimental results were either positive, negtive or neutral. Several factors may be related to these seemingly controversial results: differences in ecosystem types and soil properties, soil carbon detection methods, soil depths, and contents of soil labile and recalcitrant carbon that affect the responses to nitrogen additions, all could cause discrepancies and variations in carbon sequestration. The several processes that contribute to enhance soil organic carbon storage include increasing litter input, decresing soil carbon output, particularly, by supressed decomposition of recalcitrant carbon, promoting soil humifiction and formation of recalcitrant carbon storage. However, there are still many uncertainties associated with these issues. To improve our understanding, the research about carbon in deep soil layers, dissolved organic carbon leaching and accumulation, and the effect of labile and recalcitrant soil C ratios on N addition responses, should be further investigated in the future studies.     

土壤有机碳对外源氮添加的响应及其机制

土壤有机碳库是陆地生态系统碳库的重要组成, 在全球碳循环中发挥着重要的作用。受元素化学计量平衡调控作用, 氮输入的增加将会对土壤有机碳库产生重要影响。然而, 目前关于陆地生态系统碳库对氮添加的响应主要集中在植被碳库, 对土壤碳库研究较少, 且研究结论争议较大, 尤其对其响应机制缺少系统梳理。该文作者通过对已有文献进行梳理, 认为生态系统类型、土壤碳变化的检测方法、土壤深度, 以及土壤稳定性碳和易变碳含量的差异可能是造成当前研究土壤碳汇增量(每克氮输入所增加的碳)差异的重要原因。氮添加条件下土壤有机碳的积累机制可能包括3个方面: 1)氮添加增加了凋落物输入, 促进了碳积累; 2)氮添加减少土壤碳输出, 尤其是抑制了稳定性碳的分解; 3)促进土壤腐殖质及稳定性碳的形成。此外, 该文结合当前研究中存在的不足, 提出今后需加强对深层土壤碳、土壤可溶性有机碳的淋溶及吸附, 以及不同土壤碳组分对氮添加的响应研究, 并通过改进检测方法减少氮添加条件下碳储量的测量误差。     

鄱阳湖典型湿地土壤有机碳分布及影响因子

在南矶湿地国家级自然保护区设置采样带,对鄱阳湖典型湿地土壤有机碳分布及影响因子进行了研究。结果表明:1)湿地土壤0～15、15～30、30～50cm有机碳含量分别为1.07%～3.52%、0.31%～1.96%、0.27%～0.92%,有机碳含量自表层以下急剧降低。2)湿地土壤0～50cm有机碳密度变化范围为3.02～10.19kg·m-2,其中,表层0～15cm约占42.5%～72.6%;土壤有机碳含量、碳密度均以苔草植物群落最高,其他依次为南荻群落、南荻+苔草群落、芦苇群落、水蓼群落。3)土壤水分与植物生物量是鄱阳湖湿地土壤有机碳分布的2个主要影响因子,土壤水分能解释湿地表层0～15cm有机碳40%的变异,总生物量则能解释28%的土壤有机碳变异。4)鄱阳湖湿地碳密度与长江中下游地区的湖泊湿地类型具有较好的可比性,远低于若尔盖、三江平原等冷区泥炭湿地类型。