Carbon Sink Effect Research Articles

Impact of anthropogenic sulfate deposition via precipitation on carbonate weathering in a typical industrial city in a karst basin of southwest China: A case study in Liuzhou

An analysis was performed of the hydrochemical characteristics of precipitation and river water samples collected from the Liujiang River Basin from June 2014 to May 2015, SW China to determine the carbon source and sink of carbonate weathering by anthropogenic sulfate deposition via precipitation in a typical Karst industrial city. Our findings revealed that (1) the pH of the precipitation samples has a volume-weighted mean (VWM) of 5.78 and that the acid rain rate is 12%. The enrichment factor (EF), sea salt fraction (SSF), crustal fraction (CF) and anthropogenic fraction (AF) were calculated, and the results indicated that precipitation was characterized by high concentrations of SO4, NH4, Ca and NO3. Na and Cl, Ca and NH4, and SO4 (98.2%) and NO3 (99.8%) were mainly derived from sea salt, earth crust, and anthropogenic activities, respectively. Combined with the air mass trajectory (HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory)) and the concentration of non-sea salt (NSS) SO4 and δ34S–SO4nss, the δ34S–SO4sam ranged from −2.6–12.6‰ and atmospheric sulfate was mainly associated with local coal combustion, fossil fuels and the transmission distance of pollution sources from the northwest and southwest in the interior of the continents. (2) An analysis of the river hydrochemical characteristics showed that the cations are mainly Ca and Mg, and they accounted for approximately 90% of the total cations. The anions were mainly HCO3 and SO4, and the hydrochemical composition of the river was mainly controlled by the weathering of carbonate minerals in the river basin. An analysis of the correlation between the changes in the chemical equivalence concentration of [Ca + Mg]/[HCO3+SO4] showed that the ratio of most river water samples was approximately 1, indicating that Ca and Mg in the river need HCO3 and SO4 for chemical equilibrium and that SO4 in the river may be involved in the dissolution of carbonate minerals. (3) Corrections were performed based on the chloride-normalized ratios and the contribution of each terminal element was calculated to estimate the major ions of precipitation input; the results showed that the average contribution ratio of SO4 transported to the river by anthropogenic sulfuric acid in precipitation reached 85.57%. (4) According to the proportional relationships, carbonate weathering accounts for 31.73% of the anthropogenic sulfuric acid via precipitation and would cause an approximate 6.27% increase in carbonate weathering rates but a 19.48% decrease in CO2 consumption rates. Taken together, our results revealed that even in high-carbonate areas of Southwest China, chemical weathering by sulfuric acid can reduce the carbon sink effect caused by carbonate weathering.

Spatial Heterogeneity of the Carbon Emission Effect Resulting from Urban Expansion among Three Coastal Agglomerations in China

Land-use change, particularly urban expansion, can greatly affect the carbon balance, both from the aspects of terrestrial ecosystems and anthropogenic carbon emissions. Coastal China is a typical region of rapid urban expansion, and obvious spatial heterogeneity exists from the north to south. However, the different urban change characteristics and the effect on carbon balance remain undetermined. By unifying the spatial-temporal resolution of carbon source and sink data, we effectively compared the carbon budgets of three coastal urban agglomerations in China. The results show that all of the three urban agglomerations have undergone an obvious urban expansion process, with the built-up area increasing from 1.03 × 104 km2 in 2000 to 3.06 × 104 km2 in 2013. For Beijing–Tianjin–Hebei (BTH), the built-up area gradually expanded. The built-up area in the Yangtze River Delta (YRD) gradually changed before 2007 but rapidly grew thereafter. The built-up expansion of the Pearl River Delta (PRD) passed through three growing stages and showed the largest mean patch size. Carbon emission spatial patterns in the three urban agglomerations are consistent with their economic development, from which the net ecosystem production (NEP) spatial patterns are very different. Compared to carbon emissions, NEP has a carbon sink effect and can absorb some carbon emissions, but the amounts were all much lower than the carbon emissions in the three urban agglomerations. The carbon sink effect in the Yangtze River Delta is the most obvious, with the Pearl River Delta following, and the lowest effect is in Beijing–Tianjin–Hebei. Finally, a scientific basis for policy-making is provided for viable CO2 emission mitigation policies.

Carbon sequestration of cropland and paddy soils in China: potential, driving factors, and mechanisms

AbstractThe environmental problems caused by global warming have attracted close attention of governments and scientists all over the world. As the source and sink of atmospheric carbon dioxide, cropland soil plays an important role in the global carbon cycle. Paddy soil is a major component of global cropland, and there is growing research on its carbon sequestration potential. Based on the dynamic characteristics of soil carbon sequestration in cropland, this paper reviews and synthesizes the process and mechanism of soil carbon sequestration in cropland, discusses the driving factors of soil carbon sequestration in cropland from the perspective of crop management practices, and emphatically discusses the knowledge of soil carbon sequestration potential in paddy fields in China. The main conclusions are as follows: (1) The organic carbon content of cropland soil in China is obviously lower than the global average, and the current sequestration rate of paddy soil in China is obviously lower than the potential sequestration rate, which has great potential for carbon sequestration. Since the mid‐1980s, China's agricultural soil organic carbon (SOC) has been gradually increasing, especially the carbon sink effect of rice soil in southern China. (2) Soil and crop management practices such as conservation agriculture, irrigation, integrated nutrition management, straw returning, and crop rotation can improve input efficiency, increase SOC content in the soil carbon pool, and reduce greenhouse gas emissions. (3) The research on SOC fixation mechanism has entered the micro level of soil particles. The chemical protection mechanism of clay, the physical protection mechanism of aggregates, and the biological mechanism interact and influence each other. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.

The Carbon Effects of the Urban Ecological Recreational System Based on Systems Simulation

Abstract As a major component of urban ecological systems, the urban ecological space is an important carbon pool in the urban carbon circulation. Meanwhile, its special recreational function adds to the complexity of its carbon effects. According to the carbon process and effects of the urban ecological recreational system, the Source-Leakage-Sink-Order (SLSO) framework is proposed as the basis of the four subsystems of the system model. Consisting of 63 parameters, the system dynamics model of urban ecological recreational system is constructed by using VENSIM PLE. Then the urban ecological recreational system in Shanghai under different scenarios is simulated, and the carbon sources and sinks of the system as well as the process of carbon effects such as carbon footprints are analyzed and predicted. Research shows that due to the imbalance of the spatial pattern of ecological recreational space, the carbon sink effects of the system are quite limited. The human carbon source is the main contributor of the system’s carbon sources and the carbon footprint deficit is striking. The management ability of ecological recreational space influences the carbon sink potentials of the system. In addition, the maintenance mode of ecological green space plays a non-trivial role in the composition of carbon sources.

Co-accumulation characters of soil organic carbon and nitrogen under broadleaved Korean pine and Betula platyphylla secondary forests in Changbai Mountain, China.

The retrogressive succession is an important driver for dynamics of soil organic carbon (SOC) and total nitrogen (TN). We studied the quantitative distribution and synergistic accumulation characteristics of soil organic carbon and nitrogen in the primary broadleaved Korean pine (KP) forest and Betula platyphylla (BP) secondary forest in Changbai Mountain through paired plot approach. Further, we analyzed the changes of carbon pool and carbon sink effect in temperate forest soil caused by secondary succession and their carbon-nitrogen coupling mechanism. The results showed that the BP forest accumulated more organic carbon and nitrogen in the surface and subsurface soil (0-20 cm) than the KP forest, with relatively low soil C/N. Compared with KP forest, soil organic carbon storage in BP forest (0-20 cm) was higher by 14.7 t·hm-2, equivalent to a soil carbon sink gain of 29.4 g·m-2·a-1. SOC and TN concentrations were positively correlated in each soil layer of all forest types, causing a co-accumulative relationship between SOC and TN. The coefficient of determination (R2) between SOC and TN in the upper soil layers of BP forest was significantly higher than that of the KP forest, indicating that SOC accumulation under the relatively N-rich BP forest was more dependent on the accumulation of organic nitrogen. In the upper soil layers (0-10 cm) where organic matter concentrated, there was no significant difference in light fraction organic carbon and nitrogen stock between the two forest types, whereas the content, stock, and allocation percentage of heavy fraction organic carbon and nitrogen of BP forest were all significantly higher than that of the KP forest, with an average increment of 8.5 t·hm-2 in heavy fraction organic carbon stock. Those results indicated that the increase of soil organic carbon and nitrogen during secondary succession was mainly due to the increases of soil organic carbon and nitrogen pools in mineral-bound stability. The carbon-nitrogen coupling mechanisms in litter decomposition and soil organic matter formation was an important driving mechanisms underlying the changes of soil organic carbon and nitrogen pools during secondary succession.

Analysis of carbon sink effects for saline constructed wetlands vegetated with mangroves to treat mariculture wastewater and sewage

In this study, two saline mangrove artificial wetlands, Datang Saline Constructed Wetland (DSCW) created for treating mariculture wastewater and sewage, vegetated with Avicennia marina, and Mangrove Wetland Park (MWP) created for mangrove conservation, vegetated with Rhizophora stylosa, were selected for assessment of carbon sequestration and carbon budget based on measuring greenhouse gas (GHG) emissions and net primary productivities. The average GHG flux and net carbon sequestration flux as carbon dioxide equivalent (CO2 eq.) were measured. The results showed that the GHG flux emitted from DSCW and MWP were 2,128 and 2,148 g CO2 eq./m2-yr, respectively, while the flux of net sequestered carbon was 2,909 and 3,178 g CO2 eq./m2-yr, respectively, which achieved carbon budget values of -676 and -230 g CO2 eq./m2-yr, respectively, exhibiting carbon source effects. Some amounts of N2O, with a high global warming potential of 265, emitted from both artificial wetland systems might cause high GHG flux as CO2 eq. emitted from the wetland systems. It was concluded that both the nitrogenous contents and environmental conditions suitable for microbial production of N2O might be the main factors to change the wetland systems from carbon sinks to carbon sources.

Spatial-temporal change of carbon storage and sink of wetland ecosystem in arid regions, Ningxia Plain

Accurate assessment of wetland ecosystem carbon sinks is an estimation of future atmospheric CO2 concentrations, prediction of climate change and its impact on wetland ecosystems. In this study, using remote sensing data and 351 wetland sample sites in 2015, a remote sensing multiple linear regression model (RS-MLRM) was constructed to clarify the carbon storage capacity and its changing process from 2000 to 2015 and their controlling factors in arid regions wetlands. The results are as follows: (1) The studied wetlands acted as atmospheric carbon sinks from 2000 to 2015, increasing by 3.88 × 104 tC/a. Moreover, the soil carbon sink (0–40 cm) was approximately twice that of the vegetation carbon sink. (2) Carbon sinks had a clear spatial distribution, with high concentrations in Helan and Pingluo Counties in the central Ningxia Plain. From 2005 to 2015, constructed wetlands significantly increased the carbon sink (P < 0.05) and were the main contributors to carbon sequestration, indicating that positive human intervention enhances the carbon sink effect of wetlands. (3) Human activities, policy factors, soil physical and chemical properties and nutrients were the main factors affecting carbon sink in Ningxia Plain Wetland in arid regions. (4) The results provides a scientific basis for the protection and management of wetland ecosystems in arid areas.

A review of carbon sink or source effect on artificial reservoirs

The inland water system is a key conduit in transporting carbon from land to ocean, but this conduit is not a neutral pipeline because it releases greenhouse gases into the atmosphere and also stores carbon in sediment. Currently, the role of inland waters in the global carbon cycle is modified and complicated by the huge number of reservoirs that are associated with climatic alteration due to their carbon sequestration and greenhouse gas emission functions. Moreover, reservoirs are distinct from natural rivers and lakes in various ways, promoting the emission of greenhouse gases from their surfaces and carbon accumulation in sediment through high sedimentation rates and larger ratios of watershed areas to reservoir areas. Consequently, their contributions to the global carbon cycle will increase in the coming decade as a result of an increase in the number of reservoirs. This assessment (1) demonstrates that reservoirs play a significant role in carbon burial and greenhouse gas emissions, (2) defines factors that influence the carbon budget of reservoirs, and (3) explains how reservoirs affect global climatic change. According to previous findings, reservoirs could serve as carbon sinks or sources, depending on the age, location, and climate of the given reservoir. Further, the magnitude of carbon burial and greenhouse gas emissions in reservoirs depends on productivity, land use, geology, water body type, and watershed morphometry. So far, few studies have examined both carbon storage and greenhouse gas emissions in reservoirs, and many efforts to quantify burial and emissions have been compromised by limited data availability. In this review, we mainly focus on recent literature on carbon burial and greenhouse gas emissions in reservoirs and global estimates of terrestrial carbon input to inland waters.

长白山原始针叶林沼泽湿地生态系统碳储量

PDF HTML阅读 XML下载 导出引用 引用提醒 长白山原始针叶林沼泽湿地生态系统碳储量 DOI: 10.5846/stxb201802220375 作者: 作者单位: 东北林业大学生态研究中心,东北林业大学生态研究中心,东北林业大学生态研究中心,东北林业大学生态研究中心 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31370461）；国家"十三五"重点研发计划项目（2016YFC050021-02） Carbon storage of a primary coniferous forested wetland ecosystem in the temperate Changbai Mountain of China Author: Affiliation: Center for Ecological Research,Northeast Forestry University,Center for Ecological Research,Northeast Forestry University,Center for Ecological Research,Northeast Forestry University,Center for Ecological Research,Northeast Forestry University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:采用年轮分析及相对生长方程法与碳/氮分析仪测定法，测定温带长白山沿湿地过渡带环境梯度依次分布的5种典型原始沼泽类型（草丛沼泽-C、灌丛沼泽-G、落叶松泥炭藓沼泽-LN、落叶松藓类沼泽-LX和落叶松苔草沼泽-LT）生态系统碳储量（植被和土壤）、植被净初级生产力与年净固碳量，定量评价温带森林湿地固碳能力及其长期碳汇作用，并揭示其沿过渡带水分环境梯度的空间分异规律。结果表明：①5种天然沼泽类型的植被碳储量（3.18±1.70）-（112.2±18.3）tC/hm2沿过渡带环境梯度总体上呈递增趋势，针叶林沼泽显著高于C和G 12.2-34.3倍，G高于C 0.6倍，且LX和LT显著高于LN 0.3-0.6倍；②土壤碳储量（296.3±42.2）-（824.50±50.79）tC/hm2沿过渡带环境梯度总体上呈递减趋势，C显著高于G和针叶林沼泽30.8%-178.3%（P < 0.05），G显著高于针叶林沼泽38.7%-112.8%，且LN和LT显著高于LX 32.8%-53.4%；③生态系统碳储量（408.42±57.53）-（827.52±50.96）tC/hm2沿过渡带环境梯度总体上也呈递减趋势，C显著高于G和针叶林沼泽30.2%-102.7%，G显著高于针叶林沼泽21.5%-55.6%，且LN和LT显著高于LX 18.8%-28.0%；④5种沼泽类型的植被净初级生产力与年净固碳量分布在（5.74±0.08）-（10.98±1.67）t hm-2 a-1和（2.44±0.03）-（5.17±0.83）tC hm-2 a-1，其中，LX和LT的植被净初级生产力显著高于C、G和LN 61.2%-91.3%和34.5%-59.6%；而在植被年净固碳量方面，3种针叶林沼泽类型均显著高于C和G 28.7%-111.9%和19.4%-96.6%。故长白山5种天然沼泽类型的植被净初级生产力与年净固碳量沿湿地过渡带环境梯度总体上呈现出阶梯式递增趋势，且仅有LX和LT达到了中国陆地植被及全球陆地植被平均固碳水平。因此，温带长白山沼草丛沼泽和灌丛沼泽长期碳汇作用强于森林沼泽，湿地碳汇管理实践中应重视草丛沼泽和灌丛沼泽的保护与恢复。 Abstract:An annual ring analysis, relative growth equation method, and carbon/nitrogen analysis assay were used to determine the ecosystem carbon stocks (vegetation and soil) of five typical types of primitive swamps (Swamp Swamp-C, Shrub Swamp-G, Larix olgensis-Sphagnum magellanicum swamp-LN, Larix olgensis-moss swamp-LX, and Larix olgensis-Carex schmidtii swamp-LT) in the transitional zone of the wetland in the temperate zone of Changbai Mountain. The results showed that ① The vegetation carbon stocks of the five natural swamp types were(3.18±1.70)-(112.2±18.3) tC/hm2, which increased gradually along the transitional zone. The conifer forest swamps had significantly higher values than did C and G by 12.2 and 34.3 times, respectively, G was higher than C by 0.6 times, and LX and LT were significantly higher than LN by 0.3 and 0.6 times; ② The soil carbon stocks of (296.3±42.2)-(824.50±50.79) tC/hm2 declined along the environmental gradient of the transitional zone, C was significantly higher than that of G and the coniferous forest swamps by 30.8%-178.3%. Coniferous forest swamps were lower by 38.7%-112.8%, and LN and LT were significantly higher than LX 32.8%-53.4%; ③ The ecosystem carbon stocks of (408.42±57.53)-(827.52±50.96) tC/hm2 also showed a decreasing trend along the transitional zone, C was significantly higher than G and coniferous forest swamps by 30.2%-102.7%, and G was significantly higher than that of coniferous forests. Marsh was higher by 21.5%-55.6%, and LN and LT were significantly higher than LX by 18.8%-28.0%; ④ The net primary productivity and annual net carbon sequestration of vegetation in the five swamp types were distributed at (5.74±0.08)-(10.98±1.67) t hm-2 a-1 and (2.44±0.03)-(5.17±0.83) tC hm-2 a-1, of which, the net primary productivity of LX and LT was significantly higher than that of C, G, and LN by 61.2%-91.3% and 34.5%-59.6%. In terms of annual net carbon sequestration of vegetation, the coniferous forest swamp types were significantly higher than those of C and G by 28.7%-111.9% and 19.4%-96.6%. That is why the net primary productivity and annual net carbon fixation of the five natural marsh types in Changbai Mountain show a stepwise increasing trend along the environmental gradient in the transitional zone of wetlands. However, only LX and LT reached the average carbon fixation of land vegetation and global terrestrial vegetation in China. Therefore, the long-term carbon sink effect of the Changbai mountain marsh swamps and shrub swamps is stronger than that of forest swamps. We should protect and restore swamps and shrub swamps in our wetland carbon sink management practices. 参考文献 相似文献 引证文献

Dynamic variation characterization of soil organic and inorganic carbon of saline-alkali paddy fields and the influence factors

The paper aims at revealing the dynamic variation characterization of soil carbon content and the influence factors. The experiments were conducted in the Qianguo irrigation area located in western Jilin Province, and the soil samples were collected from saline-alkali bare land and saline-alkali paddy fields of different reclamation years. The dynamic variations of soil organic carbon (SOC) and soil inorganic carbon (SIC) during various growing stages were analysed. The effects of soil enzymes and chemical properties on SOC and SIC were illustrated. The results showed that SOC content initially decreased at the seedling and tillering stages, then increased at the heading stage, and finally decreased at the grain filling stage. However, SIC content initially increased at the seedling and tillering stages, then decreased at the heading stage, and finally increased at the grain filling stage. Rice growth had the effect of carbon sink. Both the reclamation of paddy field and the growing stages had significant effects on SOC and SIC contents. SOC was significantly positively correlated with the available nitrogen, invertase and catalase, and was negatively correlated with SIC, pH and conductivity, while SIC presented to be totally opposite. The conductivity and catalase had significant effects on SOC contents, while the available nitrogen and conductivity had significant effects on SIC.

How water transfer could promote the carbon sink in reed wetland

The hydrologic condition is the basic attribute of the wetland ecosystem, which affects the carbon exchange process between the wetland soil and the vegetation atmosphere, and then affects the change of carbon sink. Artificial water transfer or ecological replenishment is one of the most direct and effective measures used to control wetland saturation levels. The relationship was established, between water flux, water level fluctuation and the influence of artificial water transfer, to discuss the variation of carbon sink and when to implement water transfer and how to control water (water level) to achieve carbon sink in Baiyangdian reed (Phragmites australis) wetland under the influence of artificial water transfer. The research results show the amount of carbon sink is changed only-0.72 gC/m2 (-0.08%) in spring, and the influence is minimal, which is changed -19.49 kgC/m2 (-2.10%) in summer, and the adverse effect was great, which is changed 133.85 kgC/m2 (14.41%) in autumn, but the carbon sink increases and decreases, and the carbon sequestration is unstable, which is changed 17.89 kgC/m2 (1.93%) in winter, and the effect is favorable. Therefore, according to the effect of carbon sink in reed wetland, the time in the early spring of winter (February to March) is the best water transfer time in Baiyangdian. When the water level fluctuation is controlled at 0.3 m, the carbon sink change is 230.79 kgC/m2 (9.07%), which is beneficial to the increase of carbon sink in reed wetland. The model established in this study can be helpful to understand the mechanism of carbon sink in reed wetland through artificial water transfer in Reed wetlands, also can be used in the optimal design of the ecological service function for the restoration of damaged wetland.

Effects of Straw and Biochar Addition on Soil Carbon Balance and Ecological Benefits in a Rape-maize Rotation Planting System

The effects of different straw and biochar applications on the carbon balance of a farmland ecosystem were studied under a rape-maize rotation planting system. The study explored impact of straw and biochar addition on soil carbon sequestration. A field experiment was carried out at the National Monitor Station of Soil Fertility and Fertilizer Efficiency of Purple Soils (Chongqing, China). Five treatments, i.e., control (CK, no organic material), straw only (CS), straw and microorganism (CSD), half straw and half biochar (CSBC), and biochar only (BC), were applied. In-situ cumulative emissions of soil total carbon were subsequently monitored. Based on field experiment and survey data, carbon emissions, carbon sequestration, and and economic and environmental benefits were analyzed for soil respiration, soil carbon pool, crop carbon pool, as well as the cost of agricultural inputs after straw and biochar application. The main results were:①Accumulative emissions of soil carbon during two planting seasons were all higher with treatment than in CK, and the differences between CS, CSD, and CK were significant (P<0.05). ②Compared with CK, both straw and biochar treatments increased crop yield (by 1.49%-3.92%) and crop net primary productivity (NPP) increased by 4.44%-17.90%. Largest yields and NPP during both seasons were achieved with CSD.③Net carbon sequestration was positive during both seasons in all treatments without CK, indicating a carbon sink effect. The highest net carbon sequestration was obtained with CSD (9.05 t·hm-2) and BC (10.75 t·hm-2) treatments. The lowest carbon emissions were obtained with the BC treatment, with emissions 62.69%-81.86% lower than CK. ④The highest production to cost ratio was obtained with CS treatments during the rape planting season. Application of only biochar reduced the production to cost ratio but increased the carbon trading income (466.95-561.22 yuan·hm-2).⑤BC treatment increased carbon productivity (CP) in both seasons, while the economic (CJ) and ecological benefits(CE) of BC treatment were significantly lower than with other treatments. The addition of straw increases economic and ecological benefits; however, addition of biochar reduces such benefits.

Mulch Based No‐Tillage and Compost Effects on Nitrogen Fertility in Organic Melon

Core Ideas No‐till roller crimper was confirmed to be a suitable technology for weed management. Melon yield and quality declined under no‐till roller crimped barley. Compost application and agro‐ecological service crop cultivation showed high potential carbon sink effect. Cropping systems and varieties should be adapted to no‐till roller crimper. Agro‐ecological service crop management and compost should be combined to fit the specific local conditions. Soil fertility management in organic farming systems relies on agro‐ecological service crops (ASCs, i.e break crops, living mulch) and organic compost application. This study was conducted to determine the effect of tillage, ASC termination, and compost rates on yield and soil N fertility in organic vegetable production in Central Italy. In a long‐term organic field, in a strip plot design, barley was cultivated before melon. Two termination strategies of barley (green manure–GM, flattening by the use of a roller crimper–RC) were compared with a control without barley (FA). Three compost application rates (0, 15, and 30 Mg ha−1) were studied. While the compost rates did not show any difference among compared production parameters, the combined tillage–ASC termination strategy significantly increased melon yield in the GM compared with RC treatments, probably due to the lower soil temperature under the thick barley mulch. Soil mineral N (SMN) during the melon cycle was not a limiting factor for plant growth. Mean SMN values ranged from 22 for the 2012 RC and 36 mg kg−1 for the 2012 FA. High C and N inputs in barley treatments and high compost rates indicated an N surplus, which, in the medium–long term, could represent an N storage for subsequent crops in the rotation and potentially determine C sequestration. The results demonstrated that, to assure adequate yield, the ASC mulch based no‐tillage approach should follow the redesign of the whole cropping system, taking into account the entire suite of techniques of crop management.

Global significance of the carbon cycle in the karst dynamic system: evidence from geological and ecological processes

ABSTRACT On the basis of proposing the existence of a karst carbon cycle and carbon sink at a watershed scale, this paper provides four pieces of evidence for the integration of geology and ecology during the carbon cycle processes in the karst dynamic system, and estimated the karst carbon sink effect using the methods of comparative monitoring of paired watersheds and the carbon stable isotope tracer technique. The results of the soil carbon cycle in Maocun, Guilin, showed that the soil carbon cycle in the karst area, the weathering and dissolution of carbonate rocks under the soil, resulted in a lower soil respiration of 25% in the karst area than in a non-karst area (sandstone and shale), and the carbon isotope results indicated that 13.46% of the heavy carbon of the limestone is involved in the soil carbon cycle. The comparative monitoring results in paired watersheds, suggesting that the HCO3- concentration in a karst spring is 10 times that of a rivulet in a non-karst area, while the concentration of inorganic carbon flux is 23.8 times. With both chemical stoichiometry and carbon stable isotopes, the proportion of carbon in karst springs derived from carbonate rocks was found to be 58.52% and 37.65% respectively. The comparison on carbon exchange and isotopes at the water-gas interface between the granite and carbonate rock basins in the Li River showed that the CO2 emission of the karst water is 10.92 times that of the allogenic water from the non-karst area, while the carbon isotope of HCO3- in karst water is lighter by 8.62‰. However, this does not mean that the karst water body has a larger carbon source effect. On the contrary, it means the karst water body has a greater karst carbon sink effect. When the karst subterranean stream in Zhaidi, Guilin, is exposed at the surface, carbon-rich karst water stimulated the growth of aquatic plants. The values of carbon stable isotopes in the same species of submerged plants gradually becomes heavier and heavier, and the 512 m flow process has a maximum range of 15.46‰. The calculation results showed that 12.52% of inorganic carbon is converted into organic carbon. According to the data that has been published, the global karst carbon sink flux was estimated to be 0.53-0.58 PgC/a, equivalent to 31.18%-34.41% of the global forest carbon sink flux. In the meanwhile, the karst carbon sink flux in China was calculated to be 0.051 PgC/a, accounting for 68% of its forest carbon sink flux.

Integrative analysis of carbon structure and carbon sink function for major crop production in China’s typical agriculture regions

Crop production not only creates economic values, but also has ecological functions. The carbon sink function of crops plays an important role in mitigating climate changes. This paper collected and analyzed the carbon cost data of staple crops in China, estimated the carbon sink and carbon source effects of farmlands, and quantitatively evaluated the carbon inputs and outputs of crop production systems. The results showed that the carbon footprints of crops in six typical agriculture regions were quite different, and the major crops production showed as carbon sinks in general. The carbon sequestration of different crops in the same region were significantly different, as well as the same crop in different regions. China’s farmland ecosystem showed carbon sequestration effect: the total annual net carbon sink of three major crops, rice, wheat, and corn, was about 165.76 TgC, of which rice was the highest, accounting for 48.71%. This study also proposed the key ways for energy conservation and emission reduction of crop production in every region, and suggested the technology direction for improving carbon sink function. This study provided important basis for policy formulation and planning about the low-carbon agriculture development in China.

天山北麓新人工绿洲扩张过程中的碳库格局变化与碳库迁移

PDF HTML阅读 XML下载 导出引用 引用提醒 天山北麓新人工绿洲扩张过程中的碳库格局变化与碳库迁移 DOI: 10.5846/stxb201703310565 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金（41261049，41761041，41671198，41361098）；中国博士后基金面上资助（2013M532100） Changes in the carbon pool pattern and carbon pool migration during the expansion of new artificial oases in the northern foothills of Tianshan Mountains within the last 40 years Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:基于地面调查数据、气象数据和遥感数据分析了40年来天山北麓新人工绿洲迅速扩张对区域植被和土壤的碳库格局、碳库迁移及碳储量的影响，结果如下：1976-2016年，研究区农田面积占比从3.25%增加到40%以上，沼泽消失，水库干涸，灌丛大幅减少，土壤盐碱化过程停止，裸盐碱地面积40年里减少近70%，新生草地在裸盐碱地上形成；2016年6月植被有效碳储量约为0.122Tg，比1976年下降了15.7%，成为一个弱的碳源；土壤碳库在干旱地区陆地生态系统碳库中占绝对主导地位，1976年研究区（0-60cm）的土壤有机碳储量为7.814Tg，其中耕地仅占4.2%，1996年土壤有机碳储量比1976年减少12.4%，呈明显碳源特征，到2016年，耕地土壤有机碳储量占比超过50%，总碳储量与1996年相比微降1.2%，土壤碳库重新趋于稳定。其中，裸盐碱地土壤碳库在向耕地、灌丛地、草地土壤碳库的迁移过程中贡献了1.265Tg的碳储量增量，草地土壤碳库在向耕地、灌丛地碳库的迁移过程中贡献了0.894Tg的碳储量增量；若维持现有耕地规模不再进行新的垦荒活动，40a垦荒造成的土壤碳库损失可以逐渐恢复并重新形成碳汇效应。 Abstract:Based on ground survey data, meteorological data, and remote sensing data, this study analyzed the impact of regional vegetation and soil from the rapid expansion of new artificial oases in the northern foothills of Tianshan Mountains in the past 40 years on carbon pool pattern and migration and carbon sequestration.The results are as follows:from 1976 to 2016, the proportion of farmland in the study area increased from 3.25% to more than 40%. As the marsh disappeared, the reservoir dried up, the shrub cover was drastically reduced, the soil salinization process ceased, and the degree of salinization gradually decreased. Finally, new grassland has formed over bare saline-alkali soil, and there has been an approximate 70% reduction in the area of naked saline alkali over the last 40 years. The effective carbon sink of vegetation was decreased by 15.7% compared with that in 1976. The soil(0-60cm) total carbon storage in the study area in 1976 was 7.814TgC, of which, farmland only accounted for 4.2%. In 2016, the farmland soil organic carbon storage accounted for more than 50%, and the total soil carbon storage decreased slightly by 1.2% compared with that in 1996. The soil carbon pool appears to have stopped declining and has achieved a new balance. The soil carbon pools of bare soil salinity increased by 1.265TgC during the transfer of soil carbon to farmland, shrub land, and grassland soil carbon pools. The carbon stocks of grassland soils increased by 0.8934TgC during migration to the farmland and shrub land carbon pool. If the existing scale of cultivated land is well controlled, the loss of the soil carbon pool caused by the 40-year reclamation can be gradually recovered and the carbon sink effect can be re-formed. Human activities are decisive factors that influence the pattern of NPP distribution in the study area. Reclamation activities are generally carried out in arid oasis, especially in the desert intertidal zone around the old oasis during 1976 to 2016. Once oases are reclaimed and farmland extends to desert, a new artificial oasis is dramatically expanded, with a drastic change in water consumption patterns and temporal and spatial distributions, causing significant changes in the ecological environment. The overdraft of groundwater leads to the disappearance of spring overflow and the drying of reservoirs, which has negative effects on the ecological environment in the research area. Therefore, the sustainable development of water resources and future development trend of ecosystem carbon pool feedback in the process of new artificial oasis expansion should be taken seriously and demands further studies. 参考文献 相似文献 引证文献

The Current Carbon Sink Structure of China's Staple Crop Production and Its Optimization Approach

The global warming caused by heavy emissions of greenhouse gases has posed a great threat to the existence and develop- ment of mankind. The carbon sink function of crops has an important regulating effect on climate changes. Actually the production of crops can be seen as the carbon source as well as the carbon sink. In this article, the authors gather and analyze the relevant carbon emission parameters of the staple crop production system in China, estimate the carbon sink effect of farmland and its dynamic change feature and quantitatively evaluate the carbon input and output of these crop production systems. In this way, the paper provides a basis for making the low-carbon agriculture planning and policies and proposes the approach to optimizing the carbon sink structure of the

Quantification of the soil organic carbon balance in the Tai-Lake paddy soils of China

Rising temperatures and elevated atmospheric CO2 are two factors that simultaneously affect the dynamics of soil organic carbon (SOC). This study separately examines the effects arise from these two factors in Tai-Lake Paddy soils using DeNitrification–DeComposition (DNDC) model, with the currently most detailed soil database for the paddy region of China. The soil database is at a scale of 1:50,000, containing 52,034 paddy soil polygons derived from 1107 unique paddy soil profiles. Our simulations indicate that, the SOC in the top soils (0-30cm) increases 0.83, 1.09, 1.32, and 1.51Tg C under conventional management (3.44Tg C) in the 2.32Mha paddy soils of the Tai-Lake region from 2001 to 2019, respectively, with the atmospheric CO2 concentration increases at 1.5, 2.0, 2.5, and 3.0 times the normal rate (1.9ppmyear−1). By contrast, with rising air temperature of 0.5, 1.0, 1.5, 2.0, 3.0, and 4°C, the SOC decreases 0.09, 0.54, 0.69, 1.13, 1.80, and 2.51Tg C under conventional management, respectively. Thus, the effect of carbon sink induced from CO2 fertilization at the 2.0 times normal CO2 concentration increase rate could generally offset the effect of carbon source resulted from a 2.0°C air temperature increase. In addition, the paddy soils in this region tend to persistently be a sink of atmospheric CO2 under warming and elevated CO2 scenarios, even if when the air temperature has increased by 4°C. These results suggest that SOC storage in paddy soils of this region is prone to benefit from future global climate change and this carbon sequestration potential in the agro-ecosystems is likely to contribute to climate mitigation under current agricultural practices, despite any negative effects derived from warming. As a representative of paddy soils in eastern China, the insights gained from the Tai-Lake region may be potentially transferable to other paddy soils in eastern China where 95% of the total of China is located.

Modeling the CO2-effects of forest management and wood usage on a regional basis.

BackgroundAt the 15th Conference of Parties of the UN Framework Convention on Climate Change, Copenhagen, 2009, harvested wood products were identified as an additional carbon pool. This modification eliminates inconsistencies in greenhouse gas reporting by recognizing the role of the forest and timber sector in the global carbon cycle. Any additional CO2-effects related to wood usage are not considered by this modification. This results in a downward bias when the contribution of the forest and timber sector to climate change mitigation is assessed. The following article analyses the overall contribution to climate protection made by the forest management and wood utilization through CO2-emissions reduction using an example from the German state of North Rhine-Westphalia. Based on long term study periods (2011 to 2050 and 2100, respectively). Various alternative scenarios for forest management and wood usage are presented.ResultsIn the mid- to long-term (2050 and 2100, respectively) the net climate protection function of scenarios with varying levels of wood usage is higher than in scenarios without any wood usage. This is not observed for all scenarios on short and mid term evaluations.The advantages of wood usage are evident although the simulations resulted in high values for forest storage in the C pools. Even the carbon sink effect due to temporal accumulation of deadwood during the period from 2011 to 2100 is outbalanced by the potential of wood usage effects.ConclusionsA full assessment of the CO2-effects of the forest management requires an assessment of the forest supplemented with an assessment of the effects of wood usage. CO2-emission reductions through both fuel and material substitution as well as CO2 sink in wood products need to be considered.An integrated assessment of the climate protection function based on the analysis of the study’s scenarios provides decision parameters for a strategic approach to climate protection with regard to forest management and wood use at regional and national levels.The short-term evaluation of subsystems can be misleading, rendering long-term evaluations (until 2100, or even longer) more effective. This is also consistent with the inherently long-term perspective of forest management decisions and measures.

A comparative study of soil carbon transfer between forest soils in subtropical karst and clasolite areas and the karst carbon sink effect in Guilin, Guangxi, China

Elucidating soil carbon cycle in karst areas has been a major research focus, while the relationship between karst soil carbon transfer and karst carbon sinks is unclear. A comparative study of soil respiration rates, δ13C values of CO2 from soil respiration, and CO2 concentrations in forest soil layers was conducted from September 2006 to August 2008 between karst and clasolite areas of the Maocun karst underground river catchment. The main results are as follows: (1) the soil respiration rate in limestone soil from the karst area is apparently lower than that in red soil from the clasolite area. The soil respiration rate in the karst area varied from 23.12 to 271.26 mgC/m2 h, with an average of 111.57 mgC/m2 h, while the soil respiration rate in the clasolite area varied from 51.60 to 326.28 mgC/m2 h, with an average of 148.99 mgC/m2 h. Taking the averages into account, the soil respiration rate in limestone soil was 25.12 % less than that in red soil; (2) the δ13C values of soil respiration in the karst and clasolite areas were −29.35 to −18.26‰ and −29.21 to −22.60‰, respectively, with respective mean values of −22.68 and −26.21‰. The δ13C value of soil respiration in the karst area was heavier than that in the clasolite area; (3) the CO2 concentration of limestone soil profiles had a bi-directional gradient, which was more obvious in seasons with good moisture and air temperature conditions. In contrast, the CO2 concentration of red soil profile had a uni-directional gradient, that is to say, the deeper the red soil layer, the higher the CO2 concentration. Taking into account the mean values of CO2 concentration, the CO2 concentration of limestone soil ranged between 0.05 and 0.60 %, with an annual average of 0.25 %. The CO2 concentration of red soil ranged between 0.05 and 1.09 %, with an annual average of 0.57 %, which indicated that the lower soil layer CO2 could be consumed and absorbed by carbonate rock dissolution at the soil/rock interface in the karst area. In other words, karst processes in soil represented one of the carbon sinks.