Modeling changes in organic carbon stocks for distinct soils in southeastern brazil after four eucalyptus rotations using the century model

Soil organic matter (SOM) plays an important role in carbon (C) cycle and soil quality. Considering the complexity of factors that control SOM cycling and the long time it usually takes to observe changes in SOM stocks, modeling constitutes a very important tool to understand SOM cycling in forest soils. The following hypotheses were tested: (i) soil organic carbon (SOC) stocks would be higher after several rotations of eucalyptus than in low-productivity pastures; (ii) SOC values simulated by the Century model would describe the data better than the mean of observations. So, the aims of the current study were: (i) to evaluate the SOM dynamics using the Century model to simulate the changes of C stocks for two eucalyptus chronosequences in the Rio Doce Valley, Minas Gerais State, Brazil; and (ii) to compare the C stocks simulated by Century with the C stocks measured in soils of different Orders and regions of the Rio Doce Valley growing eucalyptus. In Belo Oriente (BO), short-rotation eucalyptus plantations had been cultivated for 4.0; 13.0, 22.0, 32.0 and 34.0 years, at a lower elevation and in a warmer climate, while in Virginópolis (VG), these time periods were 8.0, 19.0 and 33.0 years, at a higher elevation and in a milder climate. Soil samples were collected from the 0-20 cm layer to estimate C stocks. Results indicate that the C stocks simulated by the Century model decreased after 37 years of poorly managed pastures in areas previously covered by native forest in the regions of BO and VG. The substitution of poorly managed pastures by eucalyptus in the early 1970´s led to an average increase of C of 0.28 and 0.42 t ha-1 year-1 in BO and VG, respectively. The measured C stocks under eucalyptus in distinct soil Orders and independent regions with variable edapho-climate conditions were not far from the values estimated by the Century model (root mean square error - RMSE = 20.9; model efficiency - EF = 0.29) despite the opposite result obtained with the statistical procedure to test the identity of analytical methods. Only for lower soil C stocks, the model over-estimated the C stock in the 0-20 cm layer. Thus, the Century model is highly promising to detect changes in C stocks in distinct soil orders under eucalyptus, as well as to indicate the impact of harvest residue management on SOM in future rotations.

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Effect of deforestation and subsequent land-use management on soil carbon stocks in the South American Chaco

10.5194/soil-2017-34 ◽

2018 ◽

Author(s):

Natalia Andrea Osinaga ◽

Carina Rosa Álvarez ◽

Miguel Angel Taboada

Keyword(s):

Land Use ◽

Land Use Changes ◽

Warm Season ◽

Native Forest ◽

Continuous Cropping ◽

Organic C ◽

Soil C ◽

C Stocks ◽

Chaco Region ◽

The Impact

Abstract. Abstract. The sub-humid Chaco region of Argentina, originally covered by dry sclerophyll forest, has been subjected to clearing since the end of the '70 and replacement of the forest by no till farming. Land use changes produced a decrease in aboveground carbon stored in forests, but little is known about the impact on soil organic C stocks. The aim of this study was to evaluate soil C stocks and C fractions up to 1 m depth in soils under different land use: 20 yr continuous cropping, warm season grass pasture and native forest in 32 sites distributed over the Chaco region. The organic C stock content up to 1 m depth expressed as equivalent mass varied as follows: forest (119.3 Mg ha−1) > pasture (87.9 Mg ha−1) > continuous cropping (71.9 and 77.3 Mg ha−1), with no impact of the number of years under cropping. The most sensitive organic carbon fraction was the coarse particle fraction (2000 μm–212 μm) at 0–5 cm and 5–20 cm depth layers. Resistant carbon (

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The Global Long-Term Agricultural Experiment Network

10.5194/egusphere-egu2020-7283 ◽

2020 ◽

Author(s):

Carolina Cardoso Lisboa ◽

Jonathan Storkey ◽

Carlos Eduardo Pellegrino Cerri ◽

Christian Thierfelder ◽

Juan Andres Quincke ◽

...

Keyword(s):

Food Production ◽

Deep Understanding ◽

Agricultural Science ◽

Modeling Tools ◽

Soil C ◽

Climate Conditions ◽

C Stocks ◽

Agricultural Experiment ◽

The Impact

Balancing food production with environmentally sustainable land management can have important climate change mitigation co-benefits. Recent reports, including the IPCC latest Special Report, launched at the COP 25 in December 2019, have highlighted the significant role of soil carbon (C) stocks in agricultural soils in achieving CO2 zero emissons and contributing to CO2 removal. However, to measure the soil C balance (C-gains and C-losses), a deep understanding of the processes governing the changes in soil C stocks in agricultural systems is required as well as knowledge on the impact of management over long and short time scales under distinct climate conditions. An understanding of the mechanisms underpinning these processes depends on robust evidence-based datasets that can be applied to several different models to model soil C-dynamics over time and make predictions upon future scenarios. &#160;The datasets from long-term experiments (LTEs) can be extremely valuable to facilitate the evaluation of alternative food production systems impact/effect on soil health, as such soil C stocks. Employing modeling tools to analyse these data, would lead to better evaluation of land use and management practices and its environmental impacts around the globe. With the aim of supporting the agricultural science community in meeting this and related objetives, the Global Long-Term Agricultural Experiment Network (GLTEN) was launched in October 2019. The main goal of the network is to assemble and harmonize, following FAIR Data Principle (findable, accessible, interoperable and reusable), metadata from LTEs through the online GLTEN-Metadata Portal (https://glten.org/). This initial scientific investigation of the data shared between the experiments focusses on soil C data analyzed using free available tools to exploit and compare the trade-offs between several agricultural practices and C-offset given the distinct soil type and climate conditions. With the support of the GLTEN-members, we will start these joint analyses applying the Carbon Benefits Tools (https://banr.nrel.colostate.edu/CBP/) and the RothC Model (https://www.rothamsted.ac.uk/rothamsted-carbon-model-rothc). The progress of this collaborative work relies on the commitment and expertise of the GLTEN-members and we expect that the outcome from this investigation will support the knowledge refining and advancing the development of existing modeling tools. Furthermore, we will demonstrate the potential for the GLTEN to provide a platform that supports and facilitates collaborative research among the community.

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The carbon cycle in Mexico: past, present and future of C stocks and fluxes

Biogeosciences ◽

10.5194/bg-13-223-2016 ◽

2016 ◽

Vol 13 (1) ◽

pp. 223-238 ◽

Cited By ~ 14

Author(s):

G. Murray-Tortarolo ◽

P. Friedlingstein ◽

S. Sitch ◽

V. J. Jaramillo ◽

F. Murguía-Flores ◽

...

Keyword(s):

Field Measurements ◽

Climate Forcing ◽

Past Century ◽

Soil C ◽

C Cycle ◽

C Stocks ◽

Fertilization Effect ◽

C Stock ◽

Time Frames ◽

The Impact

Abstract. We modeled the carbon (C) cycle in Mexico with a process-based approach. We used different available products (satellite data, field measurements, models and flux towers) to estimate C stocks and fluxes in the country at three different time frames: present (defined as the period 2000–2005), the past century (1901–2000) and the remainder of this century (2010–2100). Our estimate of the gross primary productivity (GPP) for the country was 2137 ± 1023 TgC yr−1 and a total C stock of 34 506 ± 7483 TgC, with 20 347 ± 4622 TgC in vegetation and 14 159 ± 3861 in the soil.Contrary to other current estimates for recent decades, our results showed that Mexico was a C sink over the period 1990–2009 (+31 TgC yr−1) and that C accumulation over the last century amounted to 1210 ± 1040 TgC. We attributed this sink to the CO2 fertilization effect on GPP, which led to an increase of 3408 ± 1060 TgC, while both climate and land use reduced the country C stocks by −458 ± 1001 and −1740 ± 878 TgC, respectively. Under different future scenarios, the C sink will likely continue over the 21st century, with decreasing C uptake as the climate forcing becomes more extreme. Our work provides valuable insights on relevant driving processes of the C cycle such as the role of drought in drylands (e.g., grasslands and shrublands) and the impact of climate change on the mean residence time of soil C in tropical ecosystems.

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Characterization of Soil Organic Matter along an elevation gradient at Stelvio Pass (Italian Alps).

10.5194/egusphere-egu2020-10750 ◽

2020 ◽

Author(s):

Roberta Zangrando ◽

Maria del Carmen Villoslada Hidalgo ◽

Clara Turetta ◽

Nicoletta Cannone ◽

Francesco Malfasi ◽

...

Keyword(s):

Climate Change ◽

Organic Matter ◽

Soil Organic Matter ◽

Organic Carbon ◽

Elevation Gradient ◽

Total Carbon ◽

Plant Component ◽

Soil C ◽

C Cycle ◽

C Stocks

Climate Change (CC) has evident impacts on the biotic and abiotic components of ecosystems.Soil is the third largest reservoir of carbon, next to the lithosphere and the oceans, and stores approximately 1500 Gt in the top1 m depth. &#160;Even small changes in soil C stocks could have a vast impact on atmospheric CO2 concentration. Elevated surface temperature can substantially affect global C budgets and produce positive or negative feedbacks to climate change. Therefore, understanding the response of soil organic carbon (SOC) stocks to warming is of critical importance to evaluate the feedbacks between terrestrial C cycle and climate change.In comparison to other ecosystems, the areas at high altitudes and latitudes are the most vulnerable. In permafrost areas of the Northern Hemisphere the CC has already determined an increase in greenhouse gas emissions, shrub vegetation and variation in the composition of microbial communities. While numerous studies have been performed in Arctic, much less numerous are available for high altitude areas. These areas are a quarter of the emerged lands &#160;and have suffered strong impacts from the CC. Mountain permafrost makes up 14% of global permafrost, stores large quantities of organic carbon (SOC), and can release large quantities of CO2 due to climate change. However, permafrost contribution to the IPCC global budget has not yet been correctly quantified, in particular for ecosystems of prairie and shrubland, which alone could incorporate over 80Pg of C between soil and biomass. In the last decades, the plant component has undergone migration of species to higher altitudes, expansion of shrubs, variations in floristic composition and dominance, variations in area distribution. The expansion of the shrubs accelerates the regression of alpine meadows and snow valleys.The sampling activities have been carried out in July and September, from September 2017 to July 2019 in an area near Stelvio Pass (2,758 m a.s.l.) (Italian Central-Eastern Alps) along an altitude gradient. &#160;&#160;Two sampling sites located at 2600 m a.s.l. and 2200 m a.s.l. in altitude, corresponding to about 3&#176; C difference in the average annual air temperature were chosen. At the 2600 m site, warming experiments using open-top chambers (OTCs) to investigate how climate warming affects SOC were performed.In order to characterize the SOM (Soil Organic Matter), Total carbon (TC), Organic carbon (OC), Total Nitrogen (TN) and Dissolved Organic Carbon (DOC) were determined in soils. TC and TN were determined in biomass. In both soils and biomass were analyzed to quantify the distribution of stable isotopes of C and N, &#948;13C and &#948;15N.

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The undetected loss of aged carbon from boreal mineral soils

Scientific Reports ◽

10.1038/s41598-021-85506-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Geert Hensgens ◽

Hjalmar Laudon ◽

Mark S. Johnson ◽

Martin Berggren

Keyword(s):

Organic Carbon ◽

Boreal Forest ◽

Soil C ◽

Earth Systems ◽

Nuclear Bomb ◽

C Cycle ◽

Water Extractable Organic Carbon ◽

High Lability ◽

Mineral Soils ◽

Terrestrial Biomes

AbstractThe boreal forest is among the largest terrestrial biomes on earth, storing more carbon (C) than the atmosphere. Due to rapid climatic warming and enhanced human development, the boreal region may have begun transitioning from a net C sink to a net source. This raises serious concern that old biogenic soil C can be re-introduced into the modern C cycle in near future. Combining bio-decay experiments, mixing models and the Keeling plot method, we discovered a distinct old pre-bomb organic carbon fraction with high biodegradation rate. In total, 34 ± 12% of water-extractable organic carbon (WEOC) in podzols, one of the dominating boreal soil types, consisted of aged (~ 1000 year) labile C. The omission of this aged (i.e., Δ14C depleted) WEOC fraction in earlier studies is due to the co-occurrence with Δ14C enriched modern C formed following 1950s nuclear bomb testing masking its existence. High lability of aged soil WEOC and masking effects of modern Δ14C enriched C suggests that the risk for mobilization and re-introduction of this ancient C pool into the modern C cycle has gone undetected. Our findings have important implications for earth systems models in terms of climate-carbon feedbacks and the future C balance of the boreal forest.

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Impact of crop residue management on crop production and soil chemistry after seven years of crop rotation in temperate climate, loamy soils

PeerJ ◽

10.7717/peerj.4836 ◽

2018 ◽

Vol 6 ◽

pp. e4836 ◽

Cited By ~ 20

Author(s):

Marie-Pierre Hiel ◽

Sophie Barbieux ◽

Jérôme Pierreux ◽

Claire Olivier ◽

Guillaume Lobet ◽

...

Keyword(s):

Organic Carbon ◽

Crop Production ◽

Crop Residue ◽

Crop Residues ◽

Conventional Tillage ◽

Residue Management ◽

Temperate Climate ◽

Reduced Tillage ◽

Crop Residue Management ◽

The Impact

Society is increasingly demanding a more sustainable management of agro-ecosystems in a context of climate change and an ever growing global population. The fate of crop residues is one of the important management aspects under debate, since it represents an unneglectable quantity of organic matter which can be kept in or removed from the agro-ecosystem. The topic of residue management is not new, but the need for global conclusion on the impact of crop residue management on the agro-ecosystem linked to local pedo-climatic conditions has become apparent with an increasing amount of studies showing a diversity of conclusions. This study specifically focusses on temperate climate and loamy soil using a seven-year data set. Between 2008 and 2016, we compared four contrasting residue management strategies differing in the amount of crop residues returned to the soil (incorporation vs. exportation of residues) and in the type of tillage (reduced tillage (10 cm depth) vs. conventional tillage (ploughing at 25 cm depth)) in a field experiment. We assessed the impact of the crop residue management on crop production (three crops—winter wheat, faba bean and maize—cultivated over six cropping seasons), soil organic carbon content, nitrate (${\mathrm{NO}}_{3}^{-}$), phosphorus (P) and potassium (K) soil content and uptake by the crops. The main differences came primarily from the tillage practice and less from the restitution or removal of residues. All years and crops combined, conventional tillage resulted in a yield advantage of 3.4% as compared to reduced tillage, which can be partly explained by a lower germination rate observed under reduced tillage, especially during drier years. On average, only small differences were observed for total organic carbon (TOC) content of the soil, but reduced tillage resulted in a very clear stratification of TOC and also of P and K content as compared to conventional tillage. We observed no effect of residue management on the ${\mathrm{NO}}_{3}^{-}$ content, since the effect of fertilization dominated the effect of residue management. To confirm the results and enhance early tendencies, we believe that the experiment should be followed up in the future to observe whether more consistent changes in the whole agro-ecosystem functioning are present on the long term when managing residues with contrasted strategies.

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Site-level simulations of measurable soil fractions with Millennial Version 2

10.5194/ismc2021-19 ◽

2021 ◽

Author(s):

Rose Abramoff ◽

Bertrand Guenet ◽

Haicheng Zhang ◽

Katerina Georgiou ◽

Xiaofeng Xu ◽

...

Keyword(s):

Meta Analysis ◽

C Sequestration ◽

Current Understanding ◽

Century Model ◽

Mineral Association ◽

Microbial Decomposition ◽

Organic C ◽

Soil C ◽

Soil Fractions ◽

C Stocks

Soil carbon (C) models are used to predict C sequestration responses to climate and land use change. Yet, the soil models embedded in Earth system models typically do not represent processes that reflect our current understanding of soil C cycling, such as microbial decomposition, mineral association, and aggregation. Rather, they rely on conceptual pools with turnover times that are fit to bulk C stocks and/or fluxes. As measurements of soil fractions become increasingly available, soil C models that represent these measurable quantities can be evaluated more accurately. Here we present Version 2 (V2) of the Millennial model, a soil model developed to simulate C pools that can be measured by extraction or fractionation, including particulate organic C, mineral-associated organic C, aggregate C, microbial biomass, and dissolved organic C. Model processes have been updated to reflect the current understanding of mineral-association, temperature sensitivity and reaction kinetics, and different model structures were tested within an open-source framework. We evaluated the ability of Millennial V2 to simulate total soil organic C (SOC), as well as the mineral-associated and particulate fractions, using three soil fractionation data sets spanning a range of climate and geochemistry in Australia (N=495), Europe (N=176), and across the globe (N=730). Millennial V2 (RMSE = 1.98 &#8211; 4.76 kg, AIC = 597 &#8211; 1755) generally predicts SOC content better than the widely-used Century model (RMSE = 2.23 &#8211; 4.8 kg, AIC = 584 &#8211; 2271), despite an increase in process complexity and number of parameters. Millennial V2 reproduces between-site variation in SOC across a gradient of plant productivity, and predicts SOC turnover times similar to those of a global meta-analysis. Millennial V2 updates the conceptual Century model pools and processes and represents our current understanding of the roles that microbial activity, mineral association and aggregation play in soil C sequestration.

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

Earth System Dynamics ◽

10.5194/esd-10-233-2019 ◽

2019 ◽

Vol 10 (2) ◽

pp. 233-255 ◽

Cited By ~ 4

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.

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Metabolic tradeoffs and heterogeneity in microbial responses to temperature determine the fate of litter carbon in simulations of a warmer world

Biogeosciences ◽

10.5194/bg-16-4875-2019 ◽

2019 ◽

Vol 16 (24) ◽

pp. 4875-4888

Author(s):

Grace Pold ◽

Seeta A. Sistla ◽

Kristen M. DeAngelis

Keyword(s):

Empirical Studies ◽

Temperature Response ◽

Extracellular Enzyme ◽

Soil C ◽

C Cycle ◽

C Stocks ◽

Microbial Responses ◽

Higher Temperature ◽

Projected Changes ◽

Response To Temperature

Abstract. Climate change has the potential to destabilize the Earth's massive terrestrial carbon (C) stocks, but the degree to which models project this destabilization to occur depends on the kinds and complexities of microbial processes they simulate. Of particular note is carbon use efficiency (CUE), which determines the fraction of C processed by microbes that is anabolized into microbial biomass rather than lost to the atmosphere and soil as carbon dioxide and extracellular products. The temperature sensitivity of CUE is often modeled as an intrinsically fixed (homogeneous) property of the community, which contrasts with empirical data and has unknown impacts on projected changes to the soil C cycle under global warming. We used the Decomposition Model of Enzymatic Traits (DEMENT) – which simulates taxon-level litter decomposition dynamics – to explore the effects of introducing organism-level heterogeneity into the CUE response to temperature for decomposition of leaf litter under 5 ∘C of warming. We found that allowing the CUE temperature response to differ between taxa facilitated increased loss of litter C, unless fungal taxa were specifically restricted to decreasing CUE with temperature. Litter C loss was exacerbated by variable and elevated CUE at higher temperature, which effectively lowered costs for extracellular enzyme production. Together these results implicate a role for diversity of taxon-level CUE responses in driving the fate of litter C in a warmer world within DEMENT, which should be explored within the framework of additional model structures and validated with empirical studies.

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Soil carbon and nitrogen fraction dynamics affected by tillage erosion

Scientific Reports ◽

10.1038/s41598-019-53077-6 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Xiao-Jun Nie ◽

He-Bing Zhang ◽

Yan-Yan Su

Keyword(s):

Organic Carbon ◽

Soil Conservation ◽

Microbial Activities ◽

Soil C ◽

Soil Microbial ◽

Ammonium N ◽

Soil C And N ◽

Hydrolysable N ◽

The Impact ◽

Tillage Erosion

Abstract Understanding the impact of tillage erosion on soil organic carbon (SOC) and nitrogen (N) fractions is essential for targeted soil conservation in mountainous and hilly areas. However, little is known about this issue. In this study, we selected a tillage erosion-dominated hillslope from the Sichuan Basin, China, to determine the effect of tillage erosion on particulate OC (POC), dissolved OC (DOC), light fraction OC (LFOC), ammonium N (NH4+-N), nitrate N (NO3−-N) and alkali-hydrolysable N (AN). Additionally, we investigated the microbial activities in relation to soil C and N dynamics, including soil microbial biomass, β-glucosidase and urease activities. Tillage erosion induced serious soil loss in upper slope positions and soil deposition in lower slope positions. The observations of the various labile OC fraction distributions across the hillslope suggest that tillage erosion exerts less impact on DOC and LFOC dynamics but a notable effect on POC. The distribution pattern in total organic carbon under tillage erosion mainly depends on POC redistribution. The POC redistribution is a major factor affecting microbial activities. The AN is more prone to the tillage erosion impact than NH4+-N and NO3−-N. Effective soil conservation measures should be taken to weaken the adverse impacts of tillage erosion on POC and AN redistribution in sloping farmlands.

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