Management Strategies and Their Evaluation for Carbon Sequestration in Cropland

In order to deal with the global change and to reduce emission of greenhouse gas, a number of countries have strengthened studies on carbon sequestration in cropland. Carbon sequestration in cropland is not only an important component for the global carbon stock, but also is the most active part to sequestrate the carbon in soil from atmosphere. In this sense, it is of necessity and significance to strengthen the study on management of carbon sequestration in cropland. Based on the main factors affecting carbon cycle in agro-ecosystems, this paper summarizes the relevant management measures to strengthen the capacity of reducing emission of carbon and increasing the carbon sequestration in cropland, and evaluates the effects of these measures after being implemented at a regional extent.

Aboveground carbon sequestration of Cunninghamia lanceolata forests:Magnitude and drivers

Understanding the spatial variation,temporal changes,and their underlying driving forces of carbon sequestration in various forests is of great importance for understanding the carbon cycle and carbon management options.How carbon density and sequestration in various Cunninghamia lanceolata forests,extensively cultivated for timber production in subtropical China,vary with biodiversity,forest structure,environment,and cultural factors remain poorly explored,presenting a critical knowledge gap for realizing carbon sequestration supply potential through management.Based on a large-scale database of 449 permanent forest inventory plots,we quantified the spatial-temporal heterogeneity of aboveground carbon densities and carbon accumulation rates in Cunninghamia lanceolate forests in Hunan Province,China,and attributed the contributions of stand structure,environmental,and management factors to the heterogeneity using quantile age-sequence analysis,partial least squares path modeling(PLS-PM),and hot-spot analysis.The results showed lower values of carbon density and sequestration on average,in comparison with other forests in the same climate zone(i.e.,subtropics),with pronounced spatial and temporal variability.Specifically,quantile regression analysis using carbon accumulation rates along an age sequence showed large differences in carbon sequestration rates among underperformed and outperformed forests(0.50 and 1.80 Mg·ha^(-1)·yr^(-1)).PLS-PM demonstrated that maximum DBH and stand density were the main crucial drivers of aboveground carbon density from young to mature forests.Furthermore,species diversity and geotopographic factors were the significant factors causing the large discrepancy in aboveground carbon density change between low-and high-carbon-bearing forests.Hotspot analysis revealed the importance of culture attributes in shaping the geospatial patterns of carbon sequestration.Our work highlighted that retaining largesized DBH trees and increasing shade-tolerant tree species were important to enhance carbon sequestration in C.lanceolate forests.

Carbon stock and rate of carbon sequestration in Dipterocarpus forests of Manipur,Northeast India

We examined the carbon stock and rate of carbon sequestration in a tropical deciduous forest dominated by Dipterocarpus tuberculatus in Manipur,North East India.Estimation of aboveground biomass was determined by harvest method and multiplied with density of tree species.The aboveground biomass was between18.27–21.922 t ha-1and the carbon stock ranged from9.13 to 10.96 t C ha-1across forest stands.Aboveground biomass and carbon stock increased with the increase in tree girth.The rate of carbon sequestration varied from1.4722 to 4.64136 t ha-1year-1among the dominant tree species in forest stands in tropical deciduous forest area.The rate of carbon sequestration depends on species composition,the density of large trees in different girth classes,and anthropogenic disturbances in the present forest ecosystem.Further work is required to identify tree species having the highest potential to sequester CO2 from the atmosphere,which could lead to recommendations for tree plantations in a degraded ecosystem.

Short lifespan and ‘prime period’ of carbon sequestration call for multi-ages in dryland tree plantations

Enhancing forest cover is important for effective climate change mitigation.Studies suggest that drylands are promising areas for expanding forests,but conflicts arise with increased forest area and water consumption.Recent tree mortality in drylands raises concerns about carbon sequestration potential in tree plantations.Using Chinese dryland tree plantations as an example,we compared their growth with natural forests.Our results suggested plantation trees grew 1.6–2.1 times faster in juvenile phases,significantly shortening time to maturity(13.5 vs.30 years)compared to natural forests,potentially stemming from simple plantation age structures.Different from natural forests,74%of trees in plantations faced growth decline,indicating a short“prime period”for carbon sequestration and even a short lifespan.Additionally,a negative relationship between evapotranspiration and tree growth was observed in tree plantations since maturity,leading to high sensitivities of trees to vapor pressure deficit and soil water.However,this was not observed in natural forests.To address this,we suggest afforestation in drylands should consider complex age structures,ensuring a longer prime period for carbon sequestration and life expectancy in tree plantations.

Carbon sequestration in a bamboo plantation:a case study in a Mediterranean area

In the Mediterranean region,despite bamboo being an alien species that can seriously alter plant and ani-mal biocoenosis,the area occupied by bamboo plantations continues to increase,especially for the purpose to seques-ter carbon(C).However,the C dynamics in the soil-plant system when bamboo is grown outside its native area are poorly understood.Here we investigated the C mitigation potential of the fast-growing Moso bamboo(Phyllostachys edulis)introduced in Italy for climate-change mitigation.We analyzed aboveground(AGB)and belowground(as root/shoot ratio)biomass,litter and soil organic C(SOC)at O-15-and 15-30-cm depths in a 4-year-old bamboo plantation in comparison with the former annual cropland on which the bamboo was established.To have an idea of the maximum C stored at an ecosystem level,a natural forest adjacent the two sites was also considered.In the plantation,C accumulation as AGB was stimulated,with 14.8±3.1 Mg C ha^(-1) stored in 3 years;because thinning was done to remove culms from the first year,the mean sequestration rate was 4.9 Mg C ha^(-1) a^(-1).The sequestration rates were high but comparable to other fast-growing tree species in Italy(e.g.,Pinus nigra).SOC was significantly higher in the bamboo plantation than in the cropland only at the 0-15 cm depth,but SOC stock did not differ.Possibly 4 years were not enough time for a clear increase in SOC,or the high nutrient uptake by bamboos might have depleted the soil nutrients,thus inhibiting the soil organic matter formation by bacteria.In comparison,the natural forest had significantly higher C levels in all the pools.For C dynamics at an ecosystem level,the bamboo plantation on the former annual cropland led to substantial C removal from the atmosphere(about 12 Mg C ha^(-1) a^(-1)).However,despite the promising C sequestration rates by bamboo,its introduction should be carefully considered due to potential ecological problems caused by this species in overexploited environments such as the Mediterranean area.

Carbon sequestration rate,nitrogen use efficiency and rice yield responses to long-term substitution of chemical fertilizer by organic manure in a rice–rice cropping system

Combined application of chemical fertilizers with organic amendments was recommended as a strategy for improving yield,soil carbon storage,and nutrient use efficiency.However,how the long-term substitution of chemical fertilizer with organic manure affects rice yield,carbon sequestration rate(CSR),and nitrogen use efficiency(NUE)while ensuring environmental safety remains unclear.This study assessed the long-term effect of substituting chemical fertilizer with organic manure on rice yield,CSR,and NUE.It also determined the optimum substitution ratio in the acidic soil of southern China.The treatments were:(i)NPK0,unfertilized control;(ii)NPK1,100%chemical nitrogen,phosphorus,and potassium fertilizer;(iii)NPKM1,70%chemical NPK fertilizer and 30%organic manure;(iv)NPKM2,50%chemical NPK fertilizer and 50%organic manure;and(v)NPKM3,30%chemical NPK fertilizer and 70%organic manure.Milk vetch and pig manure were sources of manure for early and late rice seasons,respectively.The result showed that SOC content was higher in NPKM1,NPKM2,and NPKM3 treatments than in NPK0 and NPK1 treatments.The carbon sequestration rate increased by 140,160,and 280%under NPKM1,NPKM2,and NPKM3 treatments,respectively,compared to NPK1 treatment.Grain yield was 86.1,93.1,93.6,and 96.5%higher under NPK1,NPKM1,NPKM2,and NPKM3 treatments,respectively,compared to NPK0 treatment.The NUE in NPKM1,NPKM2,and NPKM3 treatments was higher as compared to NPK1 treatment for both rice seasons.Redundancy analysis revealed close positive relationships of CSR with C input,total N,soil C:N ratio,catalase,and humic acids,whereas NUE was closely related to grain yield,grain N content,and phenol oxidase.Furthermore,CSR and NUE negatively correlated with humin acid and soil C:P and N:P ratios.The technique for order of preference by similarity to ideal solution(TOPSIS)showed that NPKM3 treatment was the optimum strategy for improving CSR and NUE.Therefore,substituting 70%of chemical fertilizer with organic manure could be the best management option for increasing CSR and NUE in the paddy fields of southern China.

Moisture regime influence on soil carbon stock and carbon sequestration rates in semi-arid forests of the National Capital Region, India

Understanding the dynamics of soil carbon is crucial for assessing the soil carbon storage and predicting the potential of mitigating carbon dioxide from the atmosphere to the biomass and soil.The present study evaluated variations of soil carbon stock in semi-arid forests in India under diff erent moisture regimes.Soil organic carbon(SOC)and soil inorganic carbon(SIC)stocks were determined in diff erent moisture regimes i.e.monsoon,post-monsoon,winter and pre-monsoon seasons at 0–10 and>10–20 cm depths.SOC stock showed signifi cant variations under different moisture regimes.The highest SOC stock was during winter(22.81 Mg C ha−1)and lowest during the monsoon season(2.34 Mg C ha−1)among all the ridge forests under study.SOC and SIC stock under diff erent moisture regimes showed signifi cant negative correlation with soil moisture(p<0.05),as a sudden increase in soil moisture after rainfall results in an increase in carbon loss due to microbial decomposition of accumulated carbon during the dry period.There was an increase in annual SOC stock and a decrease(or no change in some cases),in SIC stock at both the depths during the study period.The SOC and SIC sequestration rates were estimated as any increase/decrease in the respective stock during each successive year.SOC sequestered ranged between 0.046 and 0.741 Mg C ha−1 y−1.Similarly,SIC sequestration ranged between 0.013 and 0.023 Mg C ha−1 y−1 over all ridge forests up to 20 cm depth.The Delhi ridge forests,which accounts to 0.007%of the semi-arid regions of India,contribute 0.25–0.32%of the national potential(semi-arid region)for SOC sequestration up to 20 cm depth.The estimates of the rate of C sequestration in this study provide a realistic image of carbon dynamics under present climatic conditions of semi-arid forests,and could be used in developing a database and formulating new strategies for carbon dioxide mitigation by enhancing soil C sequestration rates.

Emission-side drivers affecting carbon neutrality based on vegetation carbon sequestration:Evidence from China

To address climate change,the world needs deep decarbonization to achieve carbon neutrality(CN),which implies net-zero human-caused CO_(2) emissions in the atmosphere.This study used emission-side drivers,including socioeconomic and net primary productivity(NPP)-based factors,to determine the changes in CN based on vegetation carbon sequestration in the case of China during 2001-2015.Spatial exploratory analysis as well as the combined use of production-theoretical decomposition analysis(PDA)and an econometric model were also utilized.We showed that CN was significantly spatially correlated over the study period;Yunnan,Heilongjiang,and Jilin presented positive spatial autocorrelations,whereas Guizhou showed a negative spatial autocorrelation.More than half of CN declined over the period during which potential energy intensity(PEIE)and energy usage technological change were the largest negative and positive drivers for increasing CN.PEIE played a significantly negative role in increasing CN.We advise policymakers to focus more on emission-side drivers(e.g.,energy intensity)in addition to strengthening NPP management to achieve CN.

Monitoring Technologies for Marine Carbon Sequestration in Zhanjiang

Marine carbon sequestration is an important component of carbon dioxide capture, utilization and storage(CCUS) technology. It is crucial for achieving carbon peaking and carbon neutralization in China. However, CO_(2) leakage may lead to seabed geological disasters and threaten the safety of marine engineering. Therefore, it is of great significance to study the safety monitoring technology of marine carbon sequestration.Zhanjiang is industrially developed and rich in carbon sources. Owing to the good physical properties and reservoirs and trap characteristics,Zhanjiang has huge storage potential. This paper explores the disaster mechanism associated with CO_(2) leakage in marine carbon sequestration areas. Based on the analysis of the development of Zhanjiang industry and relevant domestic monitoring technologies, several suggestions for safety monitoring of marine carbon sequestration are proposed: application of offshore aquaculture platforms, expansion and application of ocean observation networks, carbon sequestration safety monitoring and sensing system. Intended to build a comprehensive and multi-level safety monitoring system for marine carbon sequestration, the outcome of this study provides assistance for the development of marine carbon sequestration in China's offshore areas.

Recent Progress in Improving Rate Performance of Cellulose-Derived Carbon Materials for Sodium-Ion Batteries

Cellulose-derived carbon is regarded as one of the most promising candidates for high-performance anode materials in sodium-ion batteries;however,its poor rate performance at higher current density remains a challenge to achieve high power density sodium-ion batteries.The present review comprehensively elucidates the structural characteristics of cellulose-based materials and cellulose-derived carbon materials,explores the limitations in enhancing rate performance arising from ion diffusion and electronic transfer at the level of cellulose-derived carbon materials,and proposes corresponding strategies to improve rate performance targeted at various precursors of cellulose-based materials.This review also presents an update on recent progress in cellulose-based materials and cellulose-derived carbon materials,with particular focuses on their molecular,crystalline,and aggregation structures.Furthermore,the relationship between storage sodium and rate performance the carbon materials is elucidated through theoretical calculations and characterization analyses.Finally,future perspectives regarding challenges and opportunities in the research field of cellulose-derived carbon anodes are briefly highlighted.

Effect of thinning intensity on the carbon sequestration of natural mixed coniferous and broadleaf forests in Xiaoxing'an Mountains, China

To study the effect of thinning intensity on the carbon sequestration by natural mixed coniferous and broad-leaf forests in Xiaoxing’an Mountains,China,we established six 100 m×100 m experimental plots in Dongfanghong For-est that varied in thinning intensity:plot A(10%),B(15%),C(20%),D(25%),E(30%),F(35%),and the control sample area(0%).A principal component analysis was performed using 50 different variables,including species diversity,soil fertility,litter characteristics,canopy structure param-eters,and seedling regeneration parameters.The effects of thinning intensity on carbon sequestration were strongest in plot E(0.75),followed by D(0.63),F(0.50),C(0.48),B(0.22),A(0.11),and the control(0.06).The composite score of plot E was the highest,indicating that the carbon sequestration effect was strongest at a thinning intensity of 30%.These findings provide useful insights that could aid the management of natural mixed coniferous and broadleaf forests in Xiaoxing’an Mountains,China.This information has implications for future studies of these forests,and the methods used could aid future ecological assessments of the natural forests in Xiaoxing’an Mountains,China.

Modeling the regional grazing impact on vegetation carbon sequestration ability in Temperate Eurasian Steppe

Anthropogenic activities profoundly influence carbon sequestration in the Eurasian Steppe. In particular, grazing has been identified as having a major effect on carbon sequestration. However, the extent to which grazing affects regional patterns or carbon sequestration is unknown. In this study, we evaluated the impact of regional grazing on grassland carbon seques- tration using the Boreal Ecosystem Productivity Simulator （BEPS） and the Shiyomi grazing model. Model performances were validated against the results from field measurements and eddy covariance （EC） sites. Model outputs showed that in 2008, the regional net primary productivity （NPP） was 79.5 g C m-2, and the net ecosystem productivity （NEP） was -6.5 g C m-2, characterizing the region as a Weak carbon source. The Mongol Steppe （MS） was identified as a carbon sink, whereas the Kazakh Steppe （KS） was either carbon neutral or a weak carbon source. The spatial patterns of grazing density are divergent between the MS and the KS. in the MS, livestock was mainly distributed in China with relatively good management, while in the KS livestock was mainly concentrated in the southern countries （especially Uzbekistan and Turkmenistan） with harsh environments and poor management. The consumption percentages of NPP in Turkmenistan, Tajikistan and Uzbekistan were 5.3, 3.3 and 1.2%, respectively, whereas the percentages in other countries were lower than 1%. Correspondingly, grazing consumption contributed to the carbon sources of Turkmenistan, Tajikistan and Uzbekistan by 11.6, 6.3 and 4.3%, respectively, while it weakened the carbon sink in Inner Mongolia, China and Mongolia by 1.6 and 0.5%. This regional pattern should be affected by different sub-regional characteristics, e.g., the continuous degradation of grassland in the southern part of the KS and the restoration of grassland in Inner Mongolia, China.

High-efficiently doping nitrogen in kapok fiber-derived hard carbon used as anode materials for boosting rate performance of sodium-ion batteries

The engineering of plant-based precursor for nitrogen doping has become one of the most promising strategies to enhance rate capability of hard carbon materials for sodium-ion batteries;however,the poor rate performance is mainly caused by lack of pyridine nitrogen,which often tends to escape because of high temperature in preparation process of hard carbon.In this paper,a high-rate kapok fiber-derived hard carbon is fabricated by cross-linking carboxyl group in 2,6-pyridinedicarboxylic acid with the exposed hydroxyl group on alkalized kapok with assistance of zinc chloride.Specially,a high nitrogen doping content of 4.24%is achieved,most of which are pyridine nitrogen;this is crucial for improving the defect sites and electronic conductivity of hard carbon.The optimized carbon with feature of high nitrogen content,abundant functional groups,degree of disorder,and large layer spacing exhibits high capacity of 401.7 mAh g^(−1)at a current density of 0.05 A g^(−1),and more importantly,good rate performance,for example,even at the current density of 2 A g^(−1),a specific capacity of 159.5 mAh g^(−1)can be obtained.These findings make plant-based hard carbon a promising candidate for commercial application of sodium-ion batteries,achieving high-rate performance with the enhanced pre-cross-linking interaction between plant precursors and dopants to optimize aromatization process by auxiliary pyrolysis.

Variations and determinants of tissue carbon concentration of 32 sympatric temperate tree species

Plant carbon(C)concentration is a fundamental trait for estimating C storage and nutrient utilization.However,the mechanisms of C concentration variations among different tree tissues and across species remains poorly understood.In this study,we explored the variations and determinants of C concentration of nine tissues from 216 individuals of 32 tree species,with particular attention on the effect of wood porosity(i.e.,non-porous wood,diffuse-porous wood,and ring-porous wood).The inter-tissue pattern of C concentration diverged across the three porosity types;metabolically active tissues(foliage and fine roots,except for the foliage of ring-porous species)generally had higher C levels compared with inactive wood.The poor inter-correlations between tissue C concentrations indicated a necessity of measuring tissue-and specific-C concentrations.Carbon concentration for almost all tissues generally decreased from non-porous,to diffuse-porous and to ring-porous.Tissue C was often positively correlated with tissue(foliage and wood)density and tree size,while negatively correlated with growth rate,depending on wood porosity.Our results highlight the mediating effect of type of wood porosity on the variation in tissue C among temperate species.The variations among tissues were more important than that among species.These findings provided insights on tissue C concentration variability of temperate forest species.

Carbon Sequestration Potential of Wetland Parks : A Case Study of Guangzhou Wetland Park

As the integration point of urban blue-green spaces,wetland parks play an important role in the construction of urban carbon pools.It is of great significance for achieving carbon neutrality and peak carbon emissions by reasonably evaluating the carbon sequestration capacity of wetland parks and optimizing wetland structure.In this paper,Guangzhou wetland park is taken as the research object.Through field research,the carbon sequestration potential of ecosystems at multiple levels,including forest vegetation,seedlings,and wetland ecosystems is studied,and policy recommendations are put forward for carbon sequestration in wetland systems.The results show that the annual carbon sequestration capacity of the wetland is 1296.59 t,and the annual net carbon sequestration value is 100485 yuan.Among the three regions,proportions of annual carbon sequestration of the forest vegetation plate,seedling plate,and wetland ecosystem plate account for 28.4%,41.3%,and 30.3%,respectively.

The Use of Seaweeds Aquaculture for Carbon Sequestration： A Strategy for Climate Change Mitigation

Seaweed has the ability to use carbon from the environment through photosynthesis to produce biomass. The aim of this study is to estimate carbon sequestration by seaweed aquaculture as a strategy for climate change mitigation. The study was undertaken at Gerupuk Bay, Lombok Island, West Nusa Tenggara Province, Indonesia. Four seaweed variants, such as Kappaphycus alvarezii var. Tambalang and Maumere, K. striatum and Eucheuma denticulatum, were cultivated with long-line system for three cultivation periods, starting from July to November, 2013. Each cultivation period was taken about 45 days. Parameters including weight increasement and carbon content of seaweeds were measured every 15 days of culture for each cultivation period in order to calculate carbon sequestration rate. The results showed that E. denticulatum had the highest carbon sequestration rate and significantly different （P 〈 0.05） compared with other variants for every cultivation period. Different seaweed variants have different capacity on carbon sequestration. Optimal utilization of the potential area for seaweed aquaculture could reduce a great quantity of CO2 from the atmosphere and help to mitigate global climate change process.

A comprehensive review of carbon sequestration of seagrass in China from 2013

Seagrass is not only known for its ecological role,but also for its high capacity on the carbon sequestration.Although the area of seagrass meadows was less than 0.2%of the world’s oceans,the yearly organic carbon burial of seagrass reached 10%of that in the ocean.Anthropogenic activities in the past two decades and the climate change have led to a significant decrease of seagrass meadow.Since seagrass is widely distributed along the coastline of China,it is necessary to put more efforts on the seagrass conservation and restoration,which will consequently be a suitable nature based solution for mitigating the climate change.This paper provides a comprehensive review on the following five aspects:1)the seagrass distribution in China;2)the role that seagrass plays in the climate mitigation;3)carbon sequestration of seagrass in China;4)loss of seagrass habitats and 5)the restoration of seagrass habitat in China since 2013.Current research gap and prospective research direction were also pointed out in this study.

Carbon Sequestration in Soil Cooperated with Organic Composts and Bio-Char during Corn (Zea mays) Cultivation

Background: The objective of this study was to estimate the carbon sequestration in soils cooperated with organic composts and bio-char during corn cultivation. Methods and Results: For the experiment, the soil texture used in this study was clay loam, and application rates of chemical fertilizer and bio-char were 230-107-190 kg·ha-1 (N-P2O5-K2O) as recommended amount after soil test and 0.2% to soil weight. The soil samples were periodically taken at every 15-day intervals during the experimental periods. The treatments consisted of cow compost, pig compost, swine digestate from aerobic digestion system, and their bio-char cooperation. For estimating soil C sequestration, it is determined by the net balance between carbon inputs and outputs during corn cultivation periods. For the experimental results, it found that applications of aerobic swine digestate, cow compost, and pig compost could sequester C by 38.9%, 82.2% and 19.7% in soil, respectively, when bio-char from rice hulls was cooperated with soil. For plant responses, application of bio-char in the corn field for carbon sequestration was not occurred the damage of corn growth. Conclusion: When bio-char from rice hulls was cooperated with soil, applications of aerobic swine digestate, cow compost, and pig compost could sequester C by 38.9%, 82.2% and 19.7% in soil, respectively. Therefore, addition of bio-char with organic composts could have a potential soil C sequestration in agricultural practices.

A Novel Process of CO_(2) Reduction and CO_(2) Sequestration Through an Innovative Accelerated Carbonation Technique

The efiect of an innovative accelerated carbonation curing technique was evaluated on concrete containing natural zeolite powder and fine aggregate as partial replacement to alleviate the CO_(2) emission up to a certain extent from the concrete production industry and improve sequestration of CO_(2) into the concrete matrix in a stable form.An accelerated carbonation curing was accomplished by subjecting the concrete specimens to 0.5 and 0.75 M concentrations of sodium bicarbonate(NaHCO_(3)) solutions up to a curing age of 180 days after the initial 28 days of normal water curing.Tests for carbonation depth,pH value,compressive strength,calcium carbonate(CaCO_(3))content,X-ray difiraction,and thermogravimetric(TGA)analyses and Fourier transform infrared spectroscopy(FTIR)were performed to measure the extent of carbonation.The obtained results showed an increment in average compressive strength for the zeolite concrete(ZLC)mixes exposed to accelerated carbonation curing.The ZLC mixes exposed to increasing NaHCO_(3) solution concentration and exposure period exhibited greater carbonation depth and decreased pH at each depth interval indicating higher CO_(2) sequestration within the concrete matrix.The results obtained from the microstructural analysis(XRD,TGA,and FTIR)and CaCO_(3) content measurements confirm that the higher amount of CaCO_(3) formation provides a clear indication of the carbonation enhancement and CO_(2) sequestration within the concrete matrix and in turn contributing to the global warming reduction.

Impacts of Climate and Nutrients on Carbon Sequestration Rate by Wetlands: A Meta-analysis

Global numerous wetlands are the most productive ecosystem and have high carbon sequestration potential to mitigate increasing CO2 in the atmosphere. However, few are available on estimating average carbon sequestration rates by global wetlands(Carbonsq) at century timescale. In this article, Carbonsq data of 473 wetland soil/sediment cores from the literatures were collected in detail by the meta-analysis method. These cores were no more than 300 years old and spanned a latitudinal range from 33.6° S to 69.7° N. Globally, the average Carbonsq was 185.2 g/(m^2·yr) regardless of wetland types. Carbonsq varied remarkably between wetland types and ranked as an order of salt marsh(247.7 g/(m^2·yr)) > mangrove(229.8 g/(m^2·yr)) > freshwater marsh(196.7 g/(m^2·yr)) > peatland(76.9 g/(m^2·yr)). Carbonsq was positively related to mean annual temperature(AMT) and annual precipitation(Pre). Nitrogen was the most common and primary factor controlling Carbonsq regardless of wetland types.