scholarly journals Comparison of soil active organic carbon fractions in different vegetation zones in purple-soil of hill slope

2020 ◽  
Vol 49 (3) ◽  
pp. 541-547
Author(s):  
Manyuan Yang ◽  
Ning Yang
Keyword(s):  
Organic Carbon ◽  
Carbon Cycle ◽  
Soil Carbon ◽  
Soil Layer ◽  
Purple Soil ◽  
Forest Zone ◽  
Vegetation Zones ◽  
Hill Slope ◽  
Active Organic Carbon ◽  
Organic Carbon Pool

To explore the effect of vegetation restoration on soil carbon cycle and fractions of soil organic carbon pool on purple-soil hill slope in Hengyang City of Hunan Province, China was selected. The soil samples of 0 - 10 and 10 - 20 cm soil layers under three types of vegetation, i.e., grassland zone (GZ), grassland-forest zone (GFZ) and forest zone (FZ). The dynamics of soil active organic carbon (SAOC) fractions to provide theory basis for the influence of soil carbon cycle and different vegetation zones on the fractions of organic carbon pool and its stability. Results show: Microbial biomass carbon and easily oxidizable organic carbon exhibited a decreasing pattern: FZ, GZ, GFZ (p < 0.05); Dissolved organic carbon exhibited a decreasing pattern: FZ, GFZ, GZ (p < 0.05); Light fraction organic carbon was the highest in FZ (p < 0.05), and the second in GZ and GFZ; The availability of active organic carbon in 0 - 10 cm soil layer was higher than that of 10 - 20 cm soil layer (p < 0.05); In comparison with GFZ, the herb in GZ could increase the contents of active organic carbon.

scholarly journals Estimating the near-surface permafrost-carbon feedback on global warming

2012 ◽  
Vol 9 (2) ◽  
pp. 649-665 ◽  
Author(s):  
T. Schneider von Deimling ◽  
M. Meinshausen ◽  
A. Levermann ◽  
V. Huber ◽  
K. Frieler ◽  
...  
Keyword(s):  
Global Warming ◽  
Carbon Cycle ◽  
Soil Carbon ◽  
Temperature Increase ◽  
Climate Model ◽  
Soil Layer ◽  
Permafrost Degradation ◽  
Near Surface ◽  
Uncertainty Range ◽  
Permafrost Thaw

Abstract. Thawing of permafrost and the associated release of carbon constitutes a positive feedback in the climate system, elevating the effect of anthropogenic GHG emissions on global-mean temperatures. Multiple factors have hindered the quantification of this feedback, which was not included in climate carbon-cycle models which participated in recent model intercomparisons (such as the Coupled Carbon Cycle Climate Model Intercomparison Project – C4MIP) . There are considerable uncertainties in the rate and extent of permafrost thaw, the hydrological and vegetation response to permafrost thaw, the decomposition timescales of freshly thawed organic material, the proportion of soil carbon that might be emitted as carbon dioxide via aerobic decomposition or as methane via anaerobic decomposition, and in the magnitude of the high latitude amplification of global warming that will drive permafrost degradation. Additionally, there are extensive and poorly characterized regional heterogeneities in soil properties, carbon content, and hydrology. Here, we couple a new permafrost module to a reduced complexity carbon-cycle climate model, which allows us to perform a large ensemble of simulations. The ensemble is designed to span the uncertainties listed above and thereby the results provide an estimate of the potential strength of the feedback from newly thawed permafrost carbon. For the high CO2 concentration scenario (RCP8.5), 33–114 GtC (giga tons of Carbon) are released by 2100 (68 % uncertainty range). This leads to an additional warming of 0.04–0.23 °C. Though projected 21st century permafrost carbon emissions are relatively modest, ongoing permafrost thaw and slow but steady soil carbon decomposition means that, by 2300, about half of the potentially vulnerable permafrost carbon stock in the upper 3 m of soil layer (600–1000 GtC) could be released as CO2, with an extra 1–4 % being released as methane. Our results also suggest that mitigation action in line with the lower scenario RCP3-PD could contain Arctic temperature increase sufficiently that thawing of the permafrost area is limited to 9–23 % and the permafrost-carbon induced temperature increase does not exceed 0.04–0.16 °C by 2300.

scholarly journals Sensitivity analysis and calibration of a soil carbon model (SoilGen2) in two contrasting loess forest soils

2012 ◽  
Vol 5 (3) ◽  
pp. 1817-1849 ◽  
Author(s):  
Y. Y. Yu ◽  
P. A. Finke ◽  
H. B. Wu ◽  
Z. T. Guo
Keyword(s):  
Sensitivity Analysis ◽  
Organic Carbon ◽  
Carbon Cycle ◽  
Soil Carbon ◽  
Decomposition Rate ◽  
Plant Material ◽  
Soil Formation ◽  
Climate Conditions ◽  
The Difference ◽  
Carbon Change

Abstract. To accurately estimate past terrestrial carbon pools is the key to understand the global carbon cycle and its relationship with the climate system. SoilGen2 is a useful tool to obtain aspects of soil properties (including carbon content) by simulating soil formation processes; thus it offers an opportunity for past soil carbon pool reconstruction. In order to apply it to various environmental conditions, parameters related to carbon cycle process in SoilGen2 are calibrated based on 6 soil pedons from two typical loess deposition regions (Belgium and China). Sensitivity analysis using Morris' method shows that decomposition rate of humus (kHUM), fraction of incoming plant material as leaf litter (frecto) and decomposition rate of resistant plant material (kRPM) are 3 most sensitive parameters that would cause the greatest uncertainty in simulated change of soil organic carbon in both regions. According to the principle of minimizing the difference between simulated and measured organic carbon by comparing quality indices, the suited values of kHUM, frecto and kRPM in the model are deduced step by step. The difference of calibrated parameters between Belgium and China may be attributed to their different vegetation types and climate conditions. This calibrated model is improved for better simulation of carbon change in the whole pedon and has potential for future modeling of carbon cycle in paleosols.

scholarly journals Estimating the permafrost-carbon feedback on global warming

2011 ◽  
Vol 8 (3) ◽  
pp. 4727-4761 ◽  
Author(s):  
T. Schneider von Deimling ◽  
M. Meinshausen ◽  
A. Levermann ◽  
V. Huber ◽  
K. Frieler ◽  
...  
Keyword(s):  
Global Warming ◽  
Carbon Cycle ◽  
Soil Carbon ◽  
Temperature Increase ◽  
Climate Model ◽  
Soil Layer ◽  
Ghg Emissions ◽  
Permafrost Degradation ◽  
Uncertainty Range ◽  
Permafrost Thaw

Abstract. Thawing of permafrost and the associated release of carbon constitutes a positive feedback in the climate system, elevating the effect of anthropogenic GHG emissions on global-mean temperatures. Multiple factors have hindered the quantification of this feedback, which was not included in the CMIP3 and C4MIP generation of AOGCMs and carbon cycle models. There are considerable uncertainties in the rate and extent of permafrost thaw, the hydrological and vegetation response to permafrost thaw, the decomposition timescales of freshly thawed organic material, the proportion of soil carbon that might be emitted as carbon dioxide via aerobic decomposition or as methane via anaerobic decomposition, and in the magnitude of the high latitude amplification of global warming that will drive permafrost degradation. Additionally, there are extensive and poorly characterized regional heterogeneities in soil properties, carbon content, and hydrology. Here, we couple a new permafrost module to a reduced complexity carbon-cycle climate model, which allows us to perform a large ensemble of simulations. The ensemble is designed to span the uncertainties listed above and thereby the results provide an estimate of the potential strength of the permafrost-carbon feedback. For the high CO2 concentration scenario (RCP8.5), 12–52 PgC, or an extra 3–11 % above projected net CO2 emissions from land carbon cycle feedbacks, are released by 2100 (68 % uncertainty range). This leads to an additional warming of 0.02–0.11 °C. Though projected 21st century emissions are relatively modest, ongoing permafrost thaw and slow but steady soil carbon decomposition means that, by 2300, more than half of the potentially vulnerable permafrost carbon stock in the upper 3m of soil layer (600–1000 PgC) could be released as CO2, with an extra 1–3 % being released as methane. Our results also suggest that mitigation action in line with the lower scenario RCP3-PD could contain Arctic temperature increase sufficiently that thawing of the permafrost area is limited to 15–30 % and the permafrost-carbon induced temperature increase does not exceed 0.01–0.07 °C by 2300.

Whole-soil profile carbon dynamic in response to climate change modulated by vertical carbon transport

2021 ◽  
Author(s):  
Mingming Wang ◽  
Zhongkui Luo
Keyword(s):  
Organic Carbon ◽  
Soil Carbon ◽  
Soil Profile ◽  
Soil Layer ◽  
Vital Role ◽  
Sensitivity Analyses ◽  
Data Sets ◽  
Organic Carbon Content ◽  
Global Pattern ◽  
Carbon Transport

&lt;p&gt;Vertical carbon transport along the soil profile redistributes soil carbon fractions in soil layers, which may have significant consequences on whole-soil profile organic carbon (SOC) dynamics. We developed three varieties of vertically resolved SOC models to simulate SOC dynamics (down to 2 m). The three models took into account mechanisms underpinning the increased persistence of SOC in deeper soil layer depths by explicitly simulating microbial processes and the interactions between old and new carbon pools. Model sensitivity analyses indicated that vertical carbon transport must to be considered; otherwise the profile distribution of SOC stock cannot be captured by the models. The models were further constrained by global data sets of whole-soil profile observations of vertical distribution of SOC stocks and carbon inputs, and then were used to predict the spatial pattern of the depth-specific amount of vertically transported organic carbon (&lt;em&gt;V&lt;/em&gt;, g C m&lt;sup&gt;-2&lt;/sup&gt; yr&lt;sup&gt;-1&lt;/sup&gt;) across the globe. The &lt;em&gt;V&lt;/em&gt; showed great variability across the globe as well as across different depths. Precipitation was the most important for influencing the global pattern of &lt;em&gt;V&lt;/em&gt;; and soil texture and organic carbon content for the profile pattern. Applying the models across the global, we assessed the response of SOC to 2&amp;#8451; global warming at the resolution of 1 km. The results suggested that without considering the vertical carbon transport, SOC loss under warming would be underestimated by 10%, particularly in the deeper layers. In wetter areas or areas with stronger soil profile disturbance such as bioturbation and cryoturbation, SOC was more sensitive (i.e., more SOC loss) to climatic warming due to the stronger vertical carbon transport and/or carbon-mixing. Our modelling demonstrates the vital role of vertical carbon transport in controlling whole-soil carbon dynamics, which is a key determinant of whole-soil profile SOC persistence under warming.&lt;/p&gt;

Effects of four typical vegetations on soil active organic carbon and soil carbon in Loess Plateau

2019 ◽  
Vol 39 (15) ◽  
Author(s):  
闫丽娟 YAN Lijuan ◽  
李广 LI Guang ◽  
吴江琪 WU Jiangqi ◽  
马维伟 MA Weiwei ◽  
王海燕 WANG Haiyan
Keyword(s):  
Organic Carbon ◽  
Soil Carbon ◽  
Loess Plateau ◽  
Active Organic Carbon

scholarly journals Soil Carbon Sequestration Potential and Linkages with General Flooding and Erosion Issues, Gisborne/East-Cape Region, North Island, New Zealand

2021 ◽  
Author(s):  
◽  
Bridget Ellen O'Leary
Keyword(s):  
Land Use ◽  
New Zealand ◽  
Carbon Sequestration ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Cycle ◽  
Soil Carbon ◽  
Land Management ◽  
Carbon Sequestration Potential ◽  
Sequestration Potential

<p>The global carbon cycle has been significantly modified by increased human demand and consumption of natural resources. Billions of tonnes of carbon moves between the Earth’s natural spheres in any given year, with anthropogenic activities adding approximately 7.1 gigatonnes (Gt) of carbon (C) to this flux. On a global basis, the sum of C in living terrestrial biomass and soils is approximately three times greater than the carbon dioxide (CO2) in the atmosphere; with the current soil organic carbon (OC) pool estimated at about 1500 Gt (Falkowski et al. 2000). With total global emissions of CO2 from soils being acknowledged as one of the largest fluxes in the carbon cycle, ideas and research into mitigating this flux are now being recognised as extremely important in terms of climate change and the reduction of green house gases (GHG) in the future. Additional co-benefits of increasing carbon storage within the soil are improvements in a soil’s structural and hydrological capacity. For example, increasing organic carbon generally increases infiltration and storage capacity of soil, with potential to reduce flooding and erosion. There are several management options that can be applied in order to increase the amount of carbon in the soil. Adjustments to land management techniques (e.g. ploughing) and also changes to cropping and vegetation type can increase organic carbon content within the subsurface (Schlesinger & Andrews, 2000). If we are able to identify specific areas of the landscape that are prone to carbon losses or have potential to be modified to store additional carbon, we can take targeted action to mitigate and apply better management strategies to these areas. This research aims to investigate issues surrounding soil carbon and the more general sustainability issues of the Gisborne/East-Cape region, North Island, New Zealand. Maori-owned land has a large presence in the region. Much of this land is described as being “marginal” in many aspects. The region also has major issues in terms of flooding and erosion. Explored within this research are issues surrounding sustainability, (including flooding, erosion, and Maori land) with particular emphasis on carbon sequestration potential and the multiple co-benefits associated with increasing the amount of carbon in the soil. This research consists of a desktop study and field investigations focusing on differences in soil type and vegetation cover/land use and what effects these differences have on soil OC content within the subsurface. Soil chemical and physical analysis was undertaken with 220 soil samples collected from two case-study properties. Particle size analysis was carried out using a laser particle sizer (LPS) to determine textural characteristics and hydraulic capacity. Soil organic carbon (OC) content was determined following the colorimetric method, wet oxidation (Blakemore et al. 1987), with results identifying large difference in soil OC quantification between sampled sites. National scale data is explored and then compared with the results from this field investigation. The direct and indirect benefits resulting from more carbon being locked up in soil may assist in determining incentives for better land-use and land management practices in the Gisborne/East-Cape region. Potentially leading to benefits for the land-user, the environment and overall general sustainability.</p>

Relative Contribution of aggregated soil Carbon to soil organic carbon pool in an Ultisol, SouthEastern Nigeria

2020 ◽  
Author(s):  
Akudo Ogechukwu Onunwa ◽  
Ifeyinwa Monica Uzoh ◽  
Chukwuebuka Christopher Okolo ◽  
Charles Arinze Igwe ◽  
John Nwite
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Carbon ◽  
Organic Amendments ◽  
Aggregate Size ◽  
Cropping System ◽  
Carbon Pool ◽  
Relative Contribution ◽  
Split Plot ◽  
Organic Carbon Pool

&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; &lt;strong&gt;ABSTRACT&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Maintenance of Soil Organic Matter (SOM) has been recognized as a strategy that could reduce soil degradation, improve soil organic carbon (SOC) pool thereby reducing atmospheric concentration of carbon iv oxide (CO&lt;sub&gt;2&lt;/sub&gt;) so as to ameliorate the effect of carbon and other greenhouse gases on the environment. Soil fertility depletion in the humid tropics is a serious problem emanating from erosion and leaching due to intense rainfall. Decrease in soil fertility and productivity is believed to be due to depletion in SOM. This study aims at determining the relative contributions (RC) of the various aggregated soil carbon (C&lt;sub&gt;WSA&lt;/sub&gt;) (which is a function of available organic matter in the soil) to Soil organic carbon pool. Soil samples were collected from an area of land (0.1125ha) planted to sole cowpea, sole maize and maize-cowpea intercrop in No till (NT) and conventionally tilled (CT) plots amended with poultry droppings (PD), pig waste (PW), cassava peels (CP) at 20t/ha each and a control in a split-split plot in Randomized Complete Block Design with three replicates. Cropping system was assigned to the main plots, tillage system was assigned to split plot while organic amendments and control was assigned to the split-split plot measuring 7.5m&lt;sup&gt;2&lt;/sup&gt;. The same treatment was maintained for two planting seasons (2012 and 2013), with the residual taken in 2013. Soil samples were collected at 0-30cm at the end of each planting season and SOC of the whole soil and the aggregated&amp;#160; soil carbon (2mm, 2-1mm,1-0.5mm 0.5-0.25mm and &lt; 0.25mm) were determined using Walkley&amp;#160; and Black method as described by Nelson and Sommers (1982). Data collected were subjected to Analysis of Variance (ANOVA) using Genstat release 7.22D. The result revealed that there is a trend of aggregate size fractions 1-0.25mm contributing more carbon to the SOC than aggregate size fractions &gt;2-1mm irrespective of the cropping system, tillage method or organic amendments applied. The highest relative contribution of aggregated soil carbon to the SOC pool shifted from the micro-aggregates (&lt;0.25mm) to the macro-aggregates (1.0-0.25mm) for as long as the organic amendments lasted but gradually returned to the micro-aggregates when the amendments were withdrawn. It is therefore recommended that organic amendments be use to improve the soil aggregation which goes a long way in improving soil carbon pool thereby ameliorating the effect of carbon and other green house gases on the environment.&lt;/p&gt;&lt;p&gt;Key Words: Soil Organic carbon pool, Soil Aggregated carbon, Relative Contribution, Macro and Micro Aggregates&lt;/p&gt;

Research Advance in Soil Organic Carbon Change

2012 ◽  
Vol 518-523 ◽  
pp. 5112-5115
Author(s):  
Zhen Hong Xie ◽  
Bo Fu ◽  
Xiang Liu
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Cycle ◽  
Soil Carbon ◽  
Carbon Storage ◽  
Soil Carbon Storage ◽  
Effect Factors ◽  
Soil Organic Carbon Storage ◽  
The Future ◽  
Organic Carbon Storage

Changes of soil organic carbon storage play an important role in carbon balance in the world. Firstly, analyzed the effect factors of the soil organic carbon changes that are limited to qualitative research instead of quantitative studies, and the main effect factors are climate and soil properties , but so far it is still unclear how the temperature changes affect soil organic carbon dynamical changes; then, summarized estimation methods of soil organic carbon storage, and the soil type method is more commonly used estimation method of soil carbon storage in china and abroad for simple method and the data easily accessible, and the study on soil organic carbon storage is static based on a point in time and is lack in dynamics analysis, therefore it is to be solved how to improve the estimation accuracy of soil carbon storage in the future; finally,summarized soil carbon cycle model at home and abroad, and it is a key point that the soil carbon cycle models combined with GIS and RS simulate large-scale soil carbon cycle in the future.

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