Assessing a new soil carbon model to simulate the effect of temperature increase on the soil carbon cycle in three eastern Canadian forest types characterized by different climatic conditions

2006 ◽  
Vol 86 (Special Issue) ◽  
pp. 187-202 ◽  
Author(s):  
Guy R. Larocque ◽  
Robert Boutin, David Paré ◽  
Gilles Robitaille ◽  
Valérie Lacerte
Keyword(s):  
Soil Respiration ◽  
Soil Carbon ◽  
Abies Balsamea ◽  
Litter Production ◽  
Forest Types ◽  
Organic C ◽  
Soil C ◽  
C Pools ◽  
C Cycle ◽  
Process Based Models

The predictive capacity of process-based models on the carbon (C) cycle in forest ecosystems is limited by the lack of knowledge on the processes involved. Thus, a better understanding of the C cycle may contribute to the development of process-based models that better represent the processes in C cycle models. A new soil C model was developed to predict the effect of an increase in the temperature regime on soil C dynamics and pools in sugar maple (Acer saccharum Marsh.), balsam fir [Abies balsamea (L.) Mill.] and black spruce [Picea mariana (Mill.) B.S.P.] forest types in Eastern Canada. Background information to calibrate the model originated from the experimental sites of the ECOLEAP project as well as from a companion study on laboratory soil incubation. Different types of litter were considered in the model: foliage, twigs, understory species, other fine detritus and fine roots. A cohort approach was used to model litter mineralization over time. The soil organic C in the organic (F and H) and mineral layers (0–20 cm) was partitioned into active, slow and passive pools and the rates of C transfer among the different pools and the amount of CO2 respired were modelled. For each forest type, there was a synchrony of response of the C pools to soil temperature variation. The results of the simulations indicated that steady state conditions were obtained under current temperature conditions. When mean annual soil temperatures were gradually increased, the litter and active and slow C pools decreased substantially, but the passive pools were minimally affected. The increase in soil respiration resulting from a gradual increase in temperature was not pronounced in comparison to changes in mineralization rates. An increase in litter production during the same period could contribute to reducing net C losses. Key words: Soil organic matter, litter, soil respiration, climate change

scholarly journals Changes in soil carbon sequestration and emission in different succession stages of biological soil crusts in a sand-binding area

2021 ◽  
Author(s):  
Bo Wang ◽  
Jing Liu ◽  
Xin Zhang ◽  
Chenglong Wang
Keyword(s):  
Soil Temperature ◽  
Soil Carbon ◽  
Water Content ◽  
Desert Soil ◽  
Desert Ecosystems ◽  
Organic C ◽  
Desert Soils ◽  
Soil C ◽  
C Cycle ◽  
Spatio Temporal

Abstract Background We investigated the spatio-temporal dynamics of soil carbon dioxide (CO2) and soil methane (CH4)-flux during biological soil crust (BSC) deposition in a sand-binding area in the eastern Chinese Hobq Desert. The trends in soil organic carbon (C) content and density were analyzed during this process. The sampling sites comprised a mobile dune (control) and those with algal, lichen, and moss crust-fixed sands. The desert soil CO2 and CH4-flux, temperature, and water content were measured from May to October in 2017 and 2018. Simultaneously, organic C content and density were measured and analyzed by stratification. Results The spatio-temporal variation in desert soil CO2-flux was apparent. The average CO2- fluxes in the control, algal, lichen, and moss sites were 1.67, 2.61, 5.83, and 6.84 mmol·m− 2·h− 1, respectively, during the growing season, and the average CH4-fluxes in the four sites were − 1.13, -1.67, -3.66, and − 3.77 µmol·m− 2·h− 1, respectively. Soil temperature was significantly positively correlated with CO2-flux but could not influence CH4 absorption, and C flux had minimal correlation with soil water content. The soil total organic C density at all sites was significantly different and decreased as follows: moss > lichen > algal > control; moreover, it decreased with soil depth at all sites. The accumulation of desert soil organic C could enhance soil C emissions. Conclusion In a semi-arid deserts, artificial planting could promote sand fixation and BSC succession; therefore, increasing the C storage capacity of desert soils and decreasing soil C emissions could alter the C cycle pattern in desert ecosystems. Soil temperature is the major factor controlling desert soil CO2 flux and vegetation restoration, and BSC development could alter the response patterns of C emissions to moisture conditions in desert soils. The results provide a scientific basis for studying the C cycle in desert ecosystems.

scholarly journals Changes in soil carbon sequestration and emission in different succession stages of biological soil crusts in a sand-binding area

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Bo Wang ◽  
Jing Liu ◽  
Xin Zhang ◽  
Chenglong Wang
Keyword(s):  
Soil Temperature ◽  
Soil Carbon ◽  
Water Content ◽  
Desert Soil ◽  
Desert Ecosystems ◽  
Organic C ◽  
Desert Soils ◽  
Soil C ◽  
C Cycle ◽  
Spatio Temporal

Abstract Background We investigated the spatio-temporal dynamics of soil carbon dioxide (CO2)- and soil methane (CH4)-flux during biological soil crust (BSCs) deposition in a sand-binding area in the eastern Chinese Hobq Desert. The trends in soil organic carbon (C) content and density were analyzed during this process. The sampling sites comprised a mobile dune (control) and those with algal, lichen, and moss crust-fixed sands. The desert soil CO2- and CH4-flux, temperature, and water content were measured from May to October in 2017 and 2018. Simultaneously, organic C content and density were measured and analyzed by stratification. Results The spatio-temporal variation in desert soil CO2-flux was apparent. The average CO2- fluxes in the control, algal, lichen, and moss sites were 1.67, 2.61, 5.83, and 6.84 mmol m−2 h−1, respectively, during the growing season, and the average CH4-fluxes in the four sites were − 1.13, − 1.67, − 3.66, and − 3.77 µmol m−2 h−1, respectively. Soil temperature was significantly positively correlated with CO2-flux but could not influence CH4 absorption, and C flux had minimal correlation with soil water content. The soil total organic C density at all sites was significantly different and decreased as follows: moss > lichen > algal > control; moreover, it decreased with soil depth at all sites. The accumulation of desert soil organic C could enhance soil C emissions. Conclusion In a semi-arid desert, artificial planting could promote sand fixation and BSCs succession; therefore, increasing the C storage capacity of desert soils and decreasing soil C emissions could alter the C cycle pattern in desert ecosystems. Soil temperature is the major factor controlling desert soil CO2 flux and vegetation restoration, and BSCs development could alter the response patterns of C emissions to moisture conditions in desert soils. The results provide a scientific basis for studying the C cycle in desert ecosystems.

scholarly journals Distinct patterns in the diurnal and seasonal variability in four components of soil respiration in a temperate forest under free-air CO<sub>2</sub> enrichment

2011 ◽  
Vol 8 (10) ◽  
pp. 3077-3092 ◽  
Author(s):  
L. Taneva ◽  
M. A. Gonzalez-Meler
Keyword(s):  
Soil Respiration ◽  
Seasonal Variability ◽  
Ecosystem Respiration ◽  
Co2 Efflux ◽  
Diurnal Variability ◽  
Soil C ◽  
Free Air ◽  
C Cycle ◽  
Strong Control ◽  
Average Contribution

Abstract. Soil respiration (RS) is a major flux in the global carbon (C) cycle. Responses of RS to changing environmental conditions may exert a strong control on the residence time of C in terrestrial ecosystems and in turn influence the atmospheric concentration of greenhouse gases. Soil respiration consists of several components oxidizing soil C from different pools, age and chemistry. The mechanisms underlying the temporal variability of RS components are poorly understood. In this study, we used the long-term whole-ecosystem 13C tracer at the Duke Forest Free Air CO2 Enrichment site to separate forest RS into its autotrophic (RR) and heterotrophic components (RH). The contribution of RH to RS was further partitioned into litter decomposition (RL), and decomposition of soil organic matter (RSOM) of two age classes – up to 8 yr old and SOM older than 8 yr. Soil respiration was generally dominated by RSOM during the growing season (44% of daytime RS), especially at night. The contribution of heterotrophic respiration (RSOM and RL) to RS was not constant, indicating that the seasonal variability in RR alone cannot explain seasonal variation in RS. Although there was no diurnal variability in RS, there were significant compensatory differences in the contribution of individual RS components to daytime and nighttime rates. The average contribution of RSOM to RS was greater at night (54%) than during the day (44%). The average contribution of RR to total RS was ~30% during the day and ~34% during the night. In contrast, RL constituted 26% of RS during the day and only 12% at night. About 95% of the decomposition of soil C older than 8 yr (Rpre-tr) originated from RSOM and showed more pronounced and consistent diurnal variability than any other RS component; nighttime rates were on average 29% higher than daytime rates. In contrast, the decomposition of more recent, post-treatment C (Rpre-tr) did not vary diurnally. None of the diurnal variations in components of RH could be explained by only temperature and moisture variations. Our results indicate that the variation observed in the components of RS is the result of complex interaction between dominant biotic controls (e.g. plant activity, mineralization kinetics, competition for substrates) over abiotic controls (temperature, moisture). The interactions and controls among roots and other soil organisms that utilize C of different chemistry, accessibility and ages, results in the overall soil CO2 efflux. Therefore understanding the controls on the components of RS is necessary to elucidate the influence of ecosystem respiration on atmospheric C-pools at different time scales.

Soil carbon sequestration with forest expansion in an arctic forest–tundra landscape

2004 ◽  
Vol 34 (7) ◽  
pp. 1538-1542 ◽  
Author(s):  
Heidi Steltzer
Keyword(s):  
Soil Carbon ◽  
Picea Glauca ◽  
White Spruce ◽  
Tree Age ◽  
Forest Expansion ◽  
Soil C ◽  
C Storage ◽  
C Pools ◽  
Sampling Locations

Soil carbon (C) and nitrogen (N) pools were measured under the canopy of 29 white spruce (Picea glauca (Moench) Voss) trees and in the surrounding tundra 3 and 6 m away from each tree at three sites of recent forest expansion along the Agashashok River in northwestern Alaska. The aim was to characterize the potential for forest expansion to lead to increased soil C pools across diverse tundra types. Soil C beneath the trees correlated positively with tree age, suggesting that tree establishment has led to C storage in the soils under their canopy at a rate of 18.5 ± 4.6 g C·m–2·year–1. Soil C in the surrounding tundra did not differ from those under the trees and showed no relationship to tree age. This characterization of the soil C pools at the 3-m scale strengthens the assertion that the pattern associated with the trees is an effect of the trees, because tree age cannot explain variation among tundra sampling locations at this scale. Potential mechanisms by which these white spruce trees could increase soil C pools include greater production and lower litter quality.

Changes in soil carbon under long-term maize in monoculture and legume-based rotation

2001 ◽  
Vol 81 (1) ◽  
pp. 21-31 ◽  
Author(s):  
E G Gregorich ◽  
C F Drury ◽  
J A Baldock
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Magnetic Resonance ◽  
Soil Carbon ◽  
Crop Residues ◽  
Cropping Systems ◽  
Natural Abundance ◽  
Organic C ◽  
Soil C

Legume-based cropping systems could help to increase crop productivity and soil organic matter levels, thereby enhancing soil quality, as well as having the additional benefit of sequestering atmospheric C. To evaluate the effects of 35 yr of maize monoculture and legume-based cropping on soil C levels and residue retention, we measured organic C and 13C natural abundance in soils under: fertilized and unfertilized maize (Zea mays L.), both in monoculture and legume-based [maize-oat (Avena sativa L.)-alfalfa (Medicago sativa L.)-alfalfa] rotations; fertilized and unfertilized systems of continuous grass (Poa pratensis L.); and under forest. Solid state 13C nuclear magnetic resonance (NMR) was used to chemically characterize the organic matter in plant residues and soils. Soils (70-cm depth) under maize cropping had about 30-40% less C, and those under continuous grass had about 16% less C, than those under adjacent forest. Qualitative differences in crop residues were important in these systems, because quantitative differences in net primary productivity and C inputs in the different agroecosystems did not account for observed differences in total soil C. Cropping sequence (i.e., rotation or monoculture) had a greater effect on soil C levels than application of fertilizer. The difference in soil C levels between rotation and monoculture maize systems was about 20 Mg C ha-1. The effects of fertilization on soil C were small (~6 Mg C ha-1), and differences were observed only in the monoculture system. The NMR results suggest that the chemical composition of organic matter was little affected by the nature of crop residues returned to the soil. The total quantity of maize-derived soil C was different in each system, because the quantity of maize residue returned to the soil was different; hence the maize-derived soil C ranged from 23 Mg ha-1 in the fertilized and 14 Mg ha-1 in the unfertilized monoculture soils (i.e., after 35 maize crops) to 6-7 Mg ha-1 in both the fertilized and unfertilized legume-based rotation soils (i.e., after eight maize crops). The proportion of maize residue C returned to the soil and retained as soil organic C (i.e., Mg maize-derived soil C/Mg maize residue) was about 14% for all maize cropping systems. The quantity of C3-C below the plow layer in legume-based rotation was 40% greater than that in monoculture and about the same as that under either continuous grass or forest. The soil organic matter below the plow layer in soil under the legume-based rotation appeared to be in a more biologically resistant form (i.e., higher aromatic C content) compared with that under monoculture. The retention of maize residue C as soil organic matter was four to five times greater below the plow layer than that within the plow layer. We conclude that residue quality plays a key role in increasing the retention of soil C in agroecosystems and that soils under legume-based rotation tend to be more “preservative” of residue C inputs, particularly from root inputs, than soils under monoculture. Key words: Soil carbon, 13C natural abundance, 13C nuclear magnetic resonance, maize cropping, legumes, root carbon

Temperature sensitivity of simulated soils with biochars produced at different temperatures

Soil Research ◽  
2019 ◽  
Vol 57 (3) ◽  
pp. 294 ◽  
Author(s):  
Xiaojie Wang ◽  
Guanhong Chen ◽  
Renduo Zhang
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Temperature Sensitivity ◽  
Pyrolysis Temperature ◽  
Soil C ◽  
Ambient Temperatures ◽  
C Pools ◽  
C Cycle ◽  
Microbial Enzyme ◽  
Different Temperatures

The temperature sensitivity of multiple carbon (C) pools in the soil plays an important role in the C cycle and potential feedback to climate change. The aim of this study was to investigate the temperature sensitivity of different biochars in soil to better understand the temperature sensitivity of different soil C pools. Biochars were prepared using sugarcane residue at temperatures of 300, 500 and 800°C (representing different C pools) and C skeletons (representing the refractory C pool in biochar) were obtained from each biochar. The sugarcane residue, biochars and C skeletons were used as amendments in a simulated soil with microbes but without organic matter. The temperature sensitivity of the amended soils was characterised by their mineralisation rate changes in response to ambient temperatures. The temperature sensitivity of treatments with relatively refractory biochars was higher than that with labile biochars. The temperature sensitivity of treatments with biochars was lower than for their corresponding C skeletons. The different temperature sensitivity of treatments was attributable to the different internal C structures (i.e. the functional groups of C=C and aromatic structure) of amendments, determining the biodegradability of substrates. Dissolved organic matter and microbial enzyme activity of biochars were lower than those of corresponding C skeletons, and decreased with increasing pyrolysis temperature. The temperature sensitivities of treatments with biochars, C skeletons and sugarcane residue were negatively correlated with the properties of dissolved organic matter and microbial enzyme activities (especially dehydrogenase) in soil.

scholarly journals Litter Traits of Native and Non-Native Tropical Trees Influence Soil Carbon Dynamics in Timber Plantations in Panama

Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 209 ◽  
Author(s):  
Deirdre Kerdraon ◽  
Julia Drewer ◽  
Biancolini Castro ◽  
Abby Wallwork ◽  
Jefferson Hall ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Soil Carbon ◽  
Tree Species ◽  
Carbon Dynamics ◽  
Additive Effects ◽  
Soil C ◽  
Soil Carbon Dynamics ◽  
Litter Mixtures ◽  
Native Tree ◽  
Native Tree Species

Tropical reforestation initiatives are widely recognized as a key strategy for mitigating rising atmospheric CO2 concentrations. Although rapid tree growth in young secondary forests and plantations sequesters large amounts of carbon (C) in biomass, the choice of tree species for reforestation projects is crucial, as species identity and diversity affect microbial activity and soil C cycling via plant litter inputs. The decay rate of litter is largely determined by its chemical and physical properties, and trait complementarity of diverse litter mixtures can produce non-additive effects, which facilitate or delay decomposition. Furthermore, microbial communities may preferentially decompose litter from native tree species (homefield advantage). Hence, information on how different tree species influence soil carbon dynamics could inform reforestation efforts to maximize soil C storage. We established a decomposition experiment in Panama, Central America, using mesocosms and litterbags in monoculture plantations of native species (Dalbergia retusa Hemsl. and Terminalia amazonia J.F.Gmel., Exell) or teak (Tectona grandis L.f.) to assess the influence of different litter types and litter mixtures on soil C dynamics. We used reciprocal litter transplant experiments to assess the homefield advantage and litter mixtures to determine facilitative or antagonistic effects on decomposition rates and soil respiration in all plantation types. Although litter properties explained some of the variation in decomposition, the microclimate and soil properties in the plantations also played an important role. Microbial biomass C and litter decomposition were lower in Tectona than in the native plantations. We observed non-additive effects of mixtures with Tectona and Dalbergia litter on both decomposition and soil respiration, but the effect depended on plantation type. Further, there was a homefield disadvantage for soil respiration in Tectona and Terminalia plantations. Our results suggest that tree species diversity plays an important role in the resilience of tropical soils and that plantations with native tree species could help maintain key processes involved in soil carbon sequestration.

scholarly journals Evaluation of terrestrial pan-Arctic carbon cycling using a data-assimilation system

2019 ◽  
Vol 10 (2) ◽  
pp. 233-255 ◽  
Author(s):  
Efrén López-Blanco ◽  
Jean-François Exbrayat ◽  
Magnus Lund ◽  
Torben R. Christensen ◽  
Mikkel P. Tamstorf ◽  
...  
Keyword(s):  
The Arctic ◽  
Soil Organic C ◽  
Area Index ◽  
Organic C ◽  
Soil C ◽  
Transit Times ◽  
C Cycle ◽  
C Stocks ◽  
Data Assimilation System ◽  
Assimilation System

Abstract. There is a significant knowledge gap in the current state of the terrestrial carbon (C) budget. Recent studies have highlighted a poor understanding particularly of C pool transit times and of whether productivity or biomass dominate these biases. The Arctic, accounting for approximately 50 % of the global soil organic C stocks, has an important role in the global C cycle. Here, we use the CARbon DAta MOdel (CARDAMOM) data-assimilation system to produce pan-Arctic terrestrial C cycle analyses for 2000–2015. This approach avoids using traditional plant functional type or steady-state assumptions. We integrate a range of data (soil organic C, leaf area index, biomass, and climate) to determine the most likely state of the high-latitude C cycle at a 1∘ × 1∘ resolution and also to provide general guidance about the controlling biases in transit times. On average, CARDAMOM estimates regional mean rates of photosynthesis of 565 g C m−2 yr−1 (90 % confidence interval between the 5th and 95th percentiles: 428, 741), autotrophic respiration of 270 g C m−2 yr−1 (182, 397) and heterotrophic respiration of 219 g C m−2 yr−1 (31, 1458), suggesting a pan-Arctic sink of −67 (−287, 1160) g Cm−2 yr−1, weaker in tundra and stronger in taiga. However, our confidence intervals remain large (and so the region could be a source of C), reflecting uncertainty assigned to the regional data products. We show a clear spatial and temporal agreement between CARDAMOM analyses and different sources of assimilated and independent data at both pan-Arctic and local scales but also identify consistent biases between CARDAMOM and validation data. The assimilation process requires clearer error quantification for leaf area index (LAI) and biomass products to resolve these biases. Mapping of vegetation C stocks and change over time and soil C ages linked to soil C stocks is required for better analytical constraint. Comparing CARDAMOM analyses to global vegetation models (GVMs) for the same period, we conclude that transit times of vegetation C are inconsistently simulated in GVMs due to a combination of uncertainties from productivity and biomass calculations. Our findings highlight that GVMs need to focus on constraining both current vegetation C stocks and net primary production to improve a process-based understanding of C cycle dynamics in the Arctic.

Quantifying total and labile pools of soil organic carbon in cultivated and uncultivated soils in eastern India

Soil Research ◽  
2018 ◽  
Vol 56 (4) ◽  
pp. 413 ◽  
Author(s):  
Kumari Priyanka ◽  
Anshumali
Keyword(s):  
Land Use ◽  
Function Analysis ◽  
Land Use Changes ◽  
C Sequestration ◽  
Sensitivity Index ◽  
Organic C ◽  
Soil C ◽  
C Pools ◽  
The Impact ◽  
Land Use Practices

Loss of labile carbon (C) fractions yields information about the impact of land-use changes on sources of C inputs, pathways of C losses and mechanisms of soil C sequestration. This study dealt with the total organic C (TOC) and labile C pools in 40 surface soil samples (0–15 cm) collected from four land-use practices: uncultivated sites and rice–wheat, maize–wheat and sugarcane agro-ecosystems. Uncultivated soils had a higher total C pool than croplands. The soil inorganic C concentrations were in the range of 0.7–1.4 g kg–1 under different land-use practices. Strong correlations were found between TOC and all organic C pools, except water-extractable organic C and mineralisable C. The sensitivity index indicated that soil organic C pools were susceptible to changes in land-use practices. Discriminant function analysis showed that the nine soil variables could distinguish the maize–wheat and rice–wheat systems from uncultivated and sugarcane systems. Finally, we recommend crop rotation practices whereby planting sugarcane replenishes TOC content in soils.

Carbon dynamics in the Brazilian Cerrado: stocks and fluxes estimated by a model data fusion framework (CARDAMOM)

2020 ◽  
Author(s):  
Eráclito Sousa-Neto ◽  
Luke Smallman ◽  
Jean Ometto ◽  
Mathew Williams
Keyword(s):  
Land Surface ◽  
Balance Model ◽  
Brazilian Cerrado ◽  
Model Framework ◽  
Area Index ◽  
Soil C ◽  
C Pools ◽  
C Cycling ◽  
C Cycle ◽  
Different Types

&lt;p&gt;Savannas are a major component of the world&amp;#8217;s vegetation and cover a land surface of about 15 Mkm&lt;sup&gt;2&lt;/sup&gt;, accounting for about 30% of the terrestrial primary production. In the South America, the Brazilian Savanna (Cerrado) is the second largest biome (2 Mkm&lt;sup&gt;2&lt;/sup&gt;), after the Amazon biome, and a hotspot of biodiversity. The Cerrado region is heterogeneous, with savanna vegetation ranging from open grassland, through a gradient of increasing tree density to nearly closed-canopy woodland. The cerrado vegetation is markedly seasonal in phenology and is often burned, either naturally or as part of a management cycle. Due its large occupation, Cerrado have the potential to influence the regional and possibly the global energy, water and carbon (C) balances. The allocation of the net primary productivity (NPP) of an ecosystem between canopy, woody tissue and fine roots is an important descriptor of the functioning of an ecosystem, and an important feature to correctly represent in terrestrial ecosystem models for carbon rates estimation, as well as their residence time, variation with climate and disturbance, and in order to make better forecasts. Such estimation in Cerrado regions remains still difficult given the lack of important soil and vegetation data. Previous studies have showed that the fluxes of water and C are closely related to each other, and to the diurnal cycle of solar radiation. However, there is no study clearly assessing the allocation of C through the different types of vegetation, either in the different types of physiognomies.&amp;#160;To help estimating the C flows across the different C pools and types of vegetation, we are using Carbon Data Model Framework (CARDAMOM) which is a computer programme that retrieves terrestrial carbon (C) cycle variables by combining C cycle observations with a mass balance model. CARDAMOM produces global dynamic estimates of plant and soil C pools, their exchanges with each other and with the atmosphere, and C cycling variables for processes driving change. It also produces a C cycle analysis consistent with C measurements and climate, and it is suited for using with global-scale satellite observations such as aboveground biomass (ABG) or leaf area index (LAI). For that, we count on field data available (AGB, BGB) and satellite data (LAI, AGB, soil C), which will help to present robust analyses of C cycling across gradients of biomass in the Brazilian Cerrado.&lt;/p&gt;

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